linux/drivers/tty/serial/msm_serial.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Driver for msm7k serial device and console
   4 *
   5 * Copyright (C) 2007 Google, Inc.
   6 * Author: Robert Love <rlove@google.com>
   7 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/atomic.h>
  12#include <linux/dma-mapping.h>
  13#include <linux/dmaengine.h>
  14#include <linux/module.h>
  15#include <linux/io.h>
  16#include <linux/ioport.h>
  17#include <linux/interrupt.h>
  18#include <linux/init.h>
  19#include <linux/console.h>
  20#include <linux/tty.h>
  21#include <linux/tty_flip.h>
  22#include <linux/serial_core.h>
  23#include <linux/slab.h>
  24#include <linux/clk.h>
  25#include <linux/platform_device.h>
  26#include <linux/delay.h>
  27#include <linux/of.h>
  28#include <linux/of_device.h>
  29#include <linux/wait.h>
  30
  31#define UART_MR1                        0x0000
  32
  33#define UART_MR1_AUTO_RFR_LEVEL0        0x3F
  34#define UART_MR1_AUTO_RFR_LEVEL1        0x3FF00
  35#define UART_DM_MR1_AUTO_RFR_LEVEL1     0xFFFFFF00
  36#define UART_MR1_RX_RDY_CTL             BIT(7)
  37#define UART_MR1_CTS_CTL                BIT(6)
  38
  39#define UART_MR2                        0x0004
  40#define UART_MR2_ERROR_MODE             BIT(6)
  41#define UART_MR2_BITS_PER_CHAR          0x30
  42#define UART_MR2_BITS_PER_CHAR_5        (0x0 << 4)
  43#define UART_MR2_BITS_PER_CHAR_6        (0x1 << 4)
  44#define UART_MR2_BITS_PER_CHAR_7        (0x2 << 4)
  45#define UART_MR2_BITS_PER_CHAR_8        (0x3 << 4)
  46#define UART_MR2_STOP_BIT_LEN_ONE       (0x1 << 2)
  47#define UART_MR2_STOP_BIT_LEN_TWO       (0x3 << 2)
  48#define UART_MR2_PARITY_MODE_NONE       0x0
  49#define UART_MR2_PARITY_MODE_ODD        0x1
  50#define UART_MR2_PARITY_MODE_EVEN       0x2
  51#define UART_MR2_PARITY_MODE_SPACE      0x3
  52#define UART_MR2_PARITY_MODE            0x3
  53
  54#define UART_CSR                        0x0008
  55
  56#define UART_TF                         0x000C
  57#define UARTDM_TF                       0x0070
  58
  59#define UART_CR                         0x0010
  60#define UART_CR_CMD_NULL                (0 << 4)
  61#define UART_CR_CMD_RESET_RX            (1 << 4)
  62#define UART_CR_CMD_RESET_TX            (2 << 4)
  63#define UART_CR_CMD_RESET_ERR           (3 << 4)
  64#define UART_CR_CMD_RESET_BREAK_INT     (4 << 4)
  65#define UART_CR_CMD_START_BREAK         (5 << 4)
  66#define UART_CR_CMD_STOP_BREAK          (6 << 4)
  67#define UART_CR_CMD_RESET_CTS           (7 << 4)
  68#define UART_CR_CMD_RESET_STALE_INT     (8 << 4)
  69#define UART_CR_CMD_PACKET_MODE         (9 << 4)
  70#define UART_CR_CMD_MODE_RESET          (12 << 4)
  71#define UART_CR_CMD_SET_RFR             (13 << 4)
  72#define UART_CR_CMD_RESET_RFR           (14 << 4)
  73#define UART_CR_CMD_PROTECTION_EN       (16 << 4)
  74#define UART_CR_CMD_STALE_EVENT_DISABLE (6 << 8)
  75#define UART_CR_CMD_STALE_EVENT_ENABLE  (80 << 4)
  76#define UART_CR_CMD_FORCE_STALE         (4 << 8)
  77#define UART_CR_CMD_RESET_TX_READY      (3 << 8)
  78#define UART_CR_TX_DISABLE              BIT(3)
  79#define UART_CR_TX_ENABLE               BIT(2)
  80#define UART_CR_RX_DISABLE              BIT(1)
  81#define UART_CR_RX_ENABLE               BIT(0)
  82#define UART_CR_CMD_RESET_RXBREAK_START ((1 << 11) | (2 << 4))
  83
  84#define UART_IMR                        0x0014
  85#define UART_IMR_TXLEV                  BIT(0)
  86#define UART_IMR_RXSTALE                BIT(3)
  87#define UART_IMR_RXLEV                  BIT(4)
  88#define UART_IMR_DELTA_CTS              BIT(5)
  89#define UART_IMR_CURRENT_CTS            BIT(6)
  90#define UART_IMR_RXBREAK_START          BIT(10)
  91
  92#define UART_IPR_RXSTALE_LAST           0x20
  93#define UART_IPR_STALE_LSB              0x1F
  94#define UART_IPR_STALE_TIMEOUT_MSB      0x3FF80
  95#define UART_DM_IPR_STALE_TIMEOUT_MSB   0xFFFFFF80
  96
  97#define UART_IPR                        0x0018
  98#define UART_TFWR                       0x001C
  99#define UART_RFWR                       0x0020
 100#define UART_HCR                        0x0024
 101
 102#define UART_MREG                       0x0028
 103#define UART_NREG                       0x002C
 104#define UART_DREG                       0x0030
 105#define UART_MNDREG                     0x0034
 106#define UART_IRDA                       0x0038
 107#define UART_MISR_MODE                  0x0040
 108#define UART_MISR_RESET                 0x0044
 109#define UART_MISR_EXPORT                0x0048
 110#define UART_MISR_VAL                   0x004C
 111#define UART_TEST_CTRL                  0x0050
 112
 113#define UART_SR                         0x0008
 114#define UART_SR_HUNT_CHAR               BIT(7)
 115#define UART_SR_RX_BREAK                BIT(6)
 116#define UART_SR_PAR_FRAME_ERR           BIT(5)
 117#define UART_SR_OVERRUN                 BIT(4)
 118#define UART_SR_TX_EMPTY                BIT(3)
 119#define UART_SR_TX_READY                BIT(2)
 120#define UART_SR_RX_FULL                 BIT(1)
 121#define UART_SR_RX_READY                BIT(0)
 122
 123#define UART_RF                         0x000C
 124#define UARTDM_RF                       0x0070
 125#define UART_MISR                       0x0010
 126#define UART_ISR                        0x0014
 127#define UART_ISR_TX_READY               BIT(7)
 128
 129#define UARTDM_RXFS                     0x50
 130#define UARTDM_RXFS_BUF_SHIFT           0x7
 131#define UARTDM_RXFS_BUF_MASK            0x7
 132
 133#define UARTDM_DMEN                     0x3C
 134#define UARTDM_DMEN_RX_SC_ENABLE        BIT(5)
 135#define UARTDM_DMEN_TX_SC_ENABLE        BIT(4)
 136
 137#define UARTDM_DMEN_TX_BAM_ENABLE       BIT(2)  /* UARTDM_1P4 */
 138#define UARTDM_DMEN_TX_DM_ENABLE        BIT(0)  /* < UARTDM_1P4 */
 139
 140#define UARTDM_DMEN_RX_BAM_ENABLE       BIT(3)  /* UARTDM_1P4 */
 141#define UARTDM_DMEN_RX_DM_ENABLE        BIT(1)  /* < UARTDM_1P4 */
 142
 143#define UARTDM_DMRX                     0x34
 144#define UARTDM_NCF_TX                   0x40
 145#define UARTDM_RX_TOTAL_SNAP            0x38
 146
 147#define UARTDM_BURST_SIZE               16   /* in bytes */
 148#define UARTDM_TX_AIGN(x)               ((x) & ~0x3) /* valid for > 1p3 */
 149#define UARTDM_TX_MAX                   256   /* in bytes, valid for <= 1p3 */
 150#define UARTDM_RX_SIZE                  (UART_XMIT_SIZE / 4)
 151
 152enum {
 153        UARTDM_1P1 = 1,
 154        UARTDM_1P2,
 155        UARTDM_1P3,
 156        UARTDM_1P4,
 157};
 158
 159struct msm_dma {
 160        struct dma_chan         *chan;
 161        enum dma_data_direction dir;
 162        dma_addr_t              phys;
 163        unsigned char           *virt;
 164        dma_cookie_t            cookie;
 165        u32                     enable_bit;
 166        unsigned int            count;
 167        struct dma_async_tx_descriptor  *desc;
 168};
 169
 170struct msm_port {
 171        struct uart_port        uart;
 172        char                    name[16];
 173        struct clk              *clk;
 174        struct clk              *pclk;
 175        unsigned int            imr;
 176        int                     is_uartdm;
 177        unsigned int            old_snap_state;
 178        bool                    break_detected;
 179        struct msm_dma          tx_dma;
 180        struct msm_dma          rx_dma;
 181};
 182
 183#define UART_TO_MSM(uart_port)  container_of(uart_port, struct msm_port, uart)
 184
 185static
 186void msm_write(struct uart_port *port, unsigned int val, unsigned int off)
 187{
 188        writel_relaxed(val, port->membase + off);
 189}
 190
 191static
 192unsigned int msm_read(struct uart_port *port, unsigned int off)
 193{
 194        return readl_relaxed(port->membase + off);
 195}
 196
 197/*
 198 * Setup the MND registers to use the TCXO clock.
 199 */
 200static void msm_serial_set_mnd_regs_tcxo(struct uart_port *port)
 201{
 202        msm_write(port, 0x06, UART_MREG);
 203        msm_write(port, 0xF1, UART_NREG);
 204        msm_write(port, 0x0F, UART_DREG);
 205        msm_write(port, 0x1A, UART_MNDREG);
 206        port->uartclk = 1843200;
 207}
 208
 209/*
 210 * Setup the MND registers to use the TCXO clock divided by 4.
 211 */
 212static void msm_serial_set_mnd_regs_tcxoby4(struct uart_port *port)
 213{
 214        msm_write(port, 0x18, UART_MREG);
 215        msm_write(port, 0xF6, UART_NREG);
 216        msm_write(port, 0x0F, UART_DREG);
 217        msm_write(port, 0x0A, UART_MNDREG);
 218        port->uartclk = 1843200;
 219}
 220
 221static void msm_serial_set_mnd_regs(struct uart_port *port)
 222{
 223        struct msm_port *msm_port = UART_TO_MSM(port);
 224
 225        /*
 226         * These registers don't exist so we change the clk input rate
 227         * on uartdm hardware instead
 228         */
 229        if (msm_port->is_uartdm)
 230                return;
 231
 232        if (port->uartclk == 19200000)
 233                msm_serial_set_mnd_regs_tcxo(port);
 234        else if (port->uartclk == 4800000)
 235                msm_serial_set_mnd_regs_tcxoby4(port);
 236}
 237
 238static void msm_handle_tx(struct uart_port *port);
 239static void msm_start_rx_dma(struct msm_port *msm_port);
 240
 241static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
 242{
 243        struct device *dev = port->dev;
 244        unsigned int mapped;
 245        u32 val;
 246
 247        mapped = dma->count;
 248        dma->count = 0;
 249
 250        dmaengine_terminate_all(dma->chan);
 251
 252        /*
 253         * DMA Stall happens if enqueue and flush command happens concurrently.
 254         * For example before changing the baud rate/protocol configuration and
 255         * sending flush command to ADM, disable the channel of UARTDM.
 256         * Note: should not reset the receiver here immediately as it is not
 257         * suggested to do disable/reset or reset/disable at the same time.
 258         */
 259        val = msm_read(port, UARTDM_DMEN);
 260        val &= ~dma->enable_bit;
 261        msm_write(port, val, UARTDM_DMEN);
 262
 263        if (mapped)
 264                dma_unmap_single(dev, dma->phys, mapped, dma->dir);
 265}
 266
 267static void msm_release_dma(struct msm_port *msm_port)
 268{
 269        struct msm_dma *dma;
 270
 271        dma = &msm_port->tx_dma;
 272        if (dma->chan) {
 273                msm_stop_dma(&msm_port->uart, dma);
 274                dma_release_channel(dma->chan);
 275        }
 276
 277        memset(dma, 0, sizeof(*dma));
 278
 279        dma = &msm_port->rx_dma;
 280        if (dma->chan) {
 281                msm_stop_dma(&msm_port->uart, dma);
 282                dma_release_channel(dma->chan);
 283                kfree(dma->virt);
 284        }
 285
 286        memset(dma, 0, sizeof(*dma));
 287}
 288
 289static void msm_request_tx_dma(struct msm_port *msm_port, resource_size_t base)
 290{
 291        struct device *dev = msm_port->uart.dev;
 292        struct dma_slave_config conf;
 293        struct msm_dma *dma;
 294        u32 crci = 0;
 295        int ret;
 296
 297        dma = &msm_port->tx_dma;
 298
 299        /* allocate DMA resources, if available */
 300        dma->chan = dma_request_chan(dev, "tx");
 301        if (IS_ERR(dma->chan))
 302                goto no_tx;
 303
 304        of_property_read_u32(dev->of_node, "qcom,tx-crci", &crci);
 305
 306        memset(&conf, 0, sizeof(conf));
 307        conf.direction = DMA_MEM_TO_DEV;
 308        conf.device_fc = true;
 309        conf.dst_addr = base + UARTDM_TF;
 310        conf.dst_maxburst = UARTDM_BURST_SIZE;
 311        conf.slave_id = crci;
 312
 313        ret = dmaengine_slave_config(dma->chan, &conf);
 314        if (ret)
 315                goto rel_tx;
 316
 317        dma->dir = DMA_TO_DEVICE;
 318
 319        if (msm_port->is_uartdm < UARTDM_1P4)
 320                dma->enable_bit = UARTDM_DMEN_TX_DM_ENABLE;
 321        else
 322                dma->enable_bit = UARTDM_DMEN_TX_BAM_ENABLE;
 323
 324        return;
 325
 326rel_tx:
 327        dma_release_channel(dma->chan);
 328no_tx:
 329        memset(dma, 0, sizeof(*dma));
 330}
 331
 332static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
 333{
 334        struct device *dev = msm_port->uart.dev;
 335        struct dma_slave_config conf;
 336        struct msm_dma *dma;
 337        u32 crci = 0;
 338        int ret;
 339
 340        dma = &msm_port->rx_dma;
 341
 342        /* allocate DMA resources, if available */
 343        dma->chan = dma_request_chan(dev, "rx");
 344        if (IS_ERR(dma->chan))
 345                goto no_rx;
 346
 347        of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
 348
 349        dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
 350        if (!dma->virt)
 351                goto rel_rx;
 352
 353        memset(&conf, 0, sizeof(conf));
 354        conf.direction = DMA_DEV_TO_MEM;
 355        conf.device_fc = true;
 356        conf.src_addr = base + UARTDM_RF;
 357        conf.src_maxburst = UARTDM_BURST_SIZE;
 358        conf.slave_id = crci;
 359
 360        ret = dmaengine_slave_config(dma->chan, &conf);
 361        if (ret)
 362                goto err;
 363
 364        dma->dir = DMA_FROM_DEVICE;
 365
 366        if (msm_port->is_uartdm < UARTDM_1P4)
 367                dma->enable_bit = UARTDM_DMEN_RX_DM_ENABLE;
 368        else
 369                dma->enable_bit = UARTDM_DMEN_RX_BAM_ENABLE;
 370
 371        return;
 372err:
 373        kfree(dma->virt);
 374rel_rx:
 375        dma_release_channel(dma->chan);
 376no_rx:
 377        memset(dma, 0, sizeof(*dma));
 378}
 379
 380static inline void msm_wait_for_xmitr(struct uart_port *port)
 381{
 382        unsigned int timeout = 500000;
 383
 384        while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
 385                if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
 386                        break;
 387                udelay(1);
 388                if (!timeout--)
 389                        break;
 390        }
 391        msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);
 392}
 393
 394static void msm_stop_tx(struct uart_port *port)
 395{
 396        struct msm_port *msm_port = UART_TO_MSM(port);
 397
 398        msm_port->imr &= ~UART_IMR_TXLEV;
 399        msm_write(port, msm_port->imr, UART_IMR);
 400}
 401
 402static void msm_start_tx(struct uart_port *port)
 403{
 404        struct msm_port *msm_port = UART_TO_MSM(port);
 405        struct msm_dma *dma = &msm_port->tx_dma;
 406
 407        /* Already started in DMA mode */
 408        if (dma->count)
 409                return;
 410
 411        msm_port->imr |= UART_IMR_TXLEV;
 412        msm_write(port, msm_port->imr, UART_IMR);
 413}
 414
 415static void msm_reset_dm_count(struct uart_port *port, int count)
 416{
 417        msm_wait_for_xmitr(port);
 418        msm_write(port, count, UARTDM_NCF_TX);
 419        msm_read(port, UARTDM_NCF_TX);
 420}
 421
 422static void msm_complete_tx_dma(void *args)
 423{
 424        struct msm_port *msm_port = args;
 425        struct uart_port *port = &msm_port->uart;
 426        struct circ_buf *xmit = &port->state->xmit;
 427        struct msm_dma *dma = &msm_port->tx_dma;
 428        struct dma_tx_state state;
 429        enum dma_status status;
 430        unsigned long flags;
 431        unsigned int count;
 432        u32 val;
 433
 434        spin_lock_irqsave(&port->lock, flags);
 435
 436        /* Already stopped */
 437        if (!dma->count)
 438                goto done;
 439
 440        status = dmaengine_tx_status(dma->chan, dma->cookie, &state);
 441
 442        dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
 443
 444        val = msm_read(port, UARTDM_DMEN);
 445        val &= ~dma->enable_bit;
 446        msm_write(port, val, UARTDM_DMEN);
 447
 448        if (msm_port->is_uartdm > UARTDM_1P3) {
 449                msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 450                msm_write(port, UART_CR_TX_ENABLE, UART_CR);
 451        }
 452
 453        count = dma->count - state.residue;
 454        port->icount.tx += count;
 455        dma->count = 0;
 456
 457        xmit->tail += count;
 458        xmit->tail &= UART_XMIT_SIZE - 1;
 459
 460        /* Restore "Tx FIFO below watermark" interrupt */
 461        msm_port->imr |= UART_IMR_TXLEV;
 462        msm_write(port, msm_port->imr, UART_IMR);
 463
 464        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 465                uart_write_wakeup(port);
 466
 467        msm_handle_tx(port);
 468done:
 469        spin_unlock_irqrestore(&port->lock, flags);
 470}
 471
 472static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
 473{
 474        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 475        struct uart_port *port = &msm_port->uart;
 476        struct msm_dma *dma = &msm_port->tx_dma;
 477        void *cpu_addr;
 478        int ret;
 479        u32 val;
 480
 481        cpu_addr = &xmit->buf[xmit->tail];
 482
 483        dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
 484        ret = dma_mapping_error(port->dev, dma->phys);
 485        if (ret)
 486                return ret;
 487
 488        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 489                                                count, DMA_MEM_TO_DEV,
 490                                                DMA_PREP_INTERRUPT |
 491                                                DMA_PREP_FENCE);
 492        if (!dma->desc) {
 493                ret = -EIO;
 494                goto unmap;
 495        }
 496
 497        dma->desc->callback = msm_complete_tx_dma;
 498        dma->desc->callback_param = msm_port;
 499
 500        dma->cookie = dmaengine_submit(dma->desc);
 501        ret = dma_submit_error(dma->cookie);
 502        if (ret)
 503                goto unmap;
 504
 505        /*
 506         * Using DMA complete for Tx FIFO reload, no need for
 507         * "Tx FIFO below watermark" one, disable it
 508         */
 509        msm_port->imr &= ~UART_IMR_TXLEV;
 510        msm_write(port, msm_port->imr, UART_IMR);
 511
 512        dma->count = count;
 513
 514        val = msm_read(port, UARTDM_DMEN);
 515        val |= dma->enable_bit;
 516
 517        if (msm_port->is_uartdm < UARTDM_1P4)
 518                msm_write(port, val, UARTDM_DMEN);
 519
 520        msm_reset_dm_count(port, count);
 521
 522        if (msm_port->is_uartdm > UARTDM_1P3)
 523                msm_write(port, val, UARTDM_DMEN);
 524
 525        dma_async_issue_pending(dma->chan);
 526        return 0;
 527unmap:
 528        dma_unmap_single(port->dev, dma->phys, count, dma->dir);
 529        return ret;
 530}
 531
 532static void msm_complete_rx_dma(void *args)
 533{
 534        struct msm_port *msm_port = args;
 535        struct uart_port *port = &msm_port->uart;
 536        struct tty_port *tport = &port->state->port;
 537        struct msm_dma *dma = &msm_port->rx_dma;
 538        int count = 0, i, sysrq;
 539        unsigned long flags;
 540        u32 val;
 541
 542        spin_lock_irqsave(&port->lock, flags);
 543
 544        /* Already stopped */
 545        if (!dma->count)
 546                goto done;
 547
 548        val = msm_read(port, UARTDM_DMEN);
 549        val &= ~dma->enable_bit;
 550        msm_write(port, val, UARTDM_DMEN);
 551
 552        if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
 553                port->icount.overrun++;
 554                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 555                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 556        }
 557
 558        count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
 559
 560        port->icount.rx += count;
 561
 562        dma->count = 0;
 563
 564        dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 565
 566        for (i = 0; i < count; i++) {
 567                char flag = TTY_NORMAL;
 568
 569                if (msm_port->break_detected && dma->virt[i] == 0) {
 570                        port->icount.brk++;
 571                        flag = TTY_BREAK;
 572                        msm_port->break_detected = false;
 573                        if (uart_handle_break(port))
 574                                continue;
 575                }
 576
 577                if (!(port->read_status_mask & UART_SR_RX_BREAK))
 578                        flag = TTY_NORMAL;
 579
 580                spin_unlock_irqrestore(&port->lock, flags);
 581                sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
 582                spin_lock_irqsave(&port->lock, flags);
 583                if (!sysrq)
 584                        tty_insert_flip_char(tport, dma->virt[i], flag);
 585        }
 586
 587        msm_start_rx_dma(msm_port);
 588done:
 589        spin_unlock_irqrestore(&port->lock, flags);
 590
 591        if (count)
 592                tty_flip_buffer_push(tport);
 593}
 594
 595static void msm_start_rx_dma(struct msm_port *msm_port)
 596{
 597        struct msm_dma *dma = &msm_port->rx_dma;
 598        struct uart_port *uart = &msm_port->uart;
 599        u32 val;
 600        int ret;
 601
 602        if (!dma->chan)
 603                return;
 604
 605        dma->phys = dma_map_single(uart->dev, dma->virt,
 606                                   UARTDM_RX_SIZE, dma->dir);
 607        ret = dma_mapping_error(uart->dev, dma->phys);
 608        if (ret)
 609                goto sw_mode;
 610
 611        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 612                                                UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
 613                                                DMA_PREP_INTERRUPT);
 614        if (!dma->desc)
 615                goto unmap;
 616
 617        dma->desc->callback = msm_complete_rx_dma;
 618        dma->desc->callback_param = msm_port;
 619
 620        dma->cookie = dmaengine_submit(dma->desc);
 621        ret = dma_submit_error(dma->cookie);
 622        if (ret)
 623                goto unmap;
 624        /*
 625         * Using DMA for FIFO off-load, no need for "Rx FIFO over
 626         * watermark" or "stale" interrupts, disable them
 627         */
 628        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 629
 630        /*
 631         * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
 632         * we need RXSTALE to flush input DMA fifo to memory
 633         */
 634        if (msm_port->is_uartdm < UARTDM_1P4)
 635                msm_port->imr |= UART_IMR_RXSTALE;
 636
 637        msm_write(uart, msm_port->imr, UART_IMR);
 638
 639        dma->count = UARTDM_RX_SIZE;
 640
 641        dma_async_issue_pending(dma->chan);
 642
 643        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 644        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 645
 646        val = msm_read(uart, UARTDM_DMEN);
 647        val |= dma->enable_bit;
 648
 649        if (msm_port->is_uartdm < UARTDM_1P4)
 650                msm_write(uart, val, UARTDM_DMEN);
 651
 652        msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
 653
 654        if (msm_port->is_uartdm > UARTDM_1P3)
 655                msm_write(uart, val, UARTDM_DMEN);
 656
 657        return;
 658unmap:
 659        dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 660
 661sw_mode:
 662        /*
 663         * Switch from DMA to SW/FIFO mode. After clearing Rx BAM (UARTDM_DMEN),
 664         * receiver must be reset.
 665         */
 666        msm_write(uart, UART_CR_CMD_RESET_RX, UART_CR);
 667        msm_write(uart, UART_CR_RX_ENABLE, UART_CR);
 668
 669        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 670        msm_write(uart, 0xFFFFFF, UARTDM_DMRX);
 671        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 672
 673        /* Re-enable RX interrupts */
 674        msm_port->imr |= (UART_IMR_RXLEV | UART_IMR_RXSTALE);
 675        msm_write(uart, msm_port->imr, UART_IMR);
 676}
 677
 678static void msm_stop_rx(struct uart_port *port)
 679{
 680        struct msm_port *msm_port = UART_TO_MSM(port);
 681        struct msm_dma *dma = &msm_port->rx_dma;
 682
 683        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 684        msm_write(port, msm_port->imr, UART_IMR);
 685
 686        if (dma->chan)
 687                msm_stop_dma(port, dma);
 688}
 689
 690static void msm_enable_ms(struct uart_port *port)
 691{
 692        struct msm_port *msm_port = UART_TO_MSM(port);
 693
 694        msm_port->imr |= UART_IMR_DELTA_CTS;
 695        msm_write(port, msm_port->imr, UART_IMR);
 696}
 697
 698static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
 699{
 700        struct tty_port *tport = &port->state->port;
 701        unsigned int sr;
 702        int count = 0;
 703        struct msm_port *msm_port = UART_TO_MSM(port);
 704
 705        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 706                port->icount.overrun++;
 707                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 708                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 709        }
 710
 711        if (misr & UART_IMR_RXSTALE) {
 712                count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
 713                        msm_port->old_snap_state;
 714                msm_port->old_snap_state = 0;
 715        } else {
 716                count = 4 * (msm_read(port, UART_RFWR));
 717                msm_port->old_snap_state += count;
 718        }
 719
 720        /* TODO: Precise error reporting */
 721
 722        port->icount.rx += count;
 723
 724        while (count > 0) {
 725                unsigned char buf[4];
 726                int sysrq, r_count, i;
 727
 728                sr = msm_read(port, UART_SR);
 729                if ((sr & UART_SR_RX_READY) == 0) {
 730                        msm_port->old_snap_state -= count;
 731                        break;
 732                }
 733
 734                ioread32_rep(port->membase + UARTDM_RF, buf, 1);
 735                r_count = min_t(int, count, sizeof(buf));
 736
 737                for (i = 0; i < r_count; i++) {
 738                        char flag = TTY_NORMAL;
 739
 740                        if (msm_port->break_detected && buf[i] == 0) {
 741                                port->icount.brk++;
 742                                flag = TTY_BREAK;
 743                                msm_port->break_detected = false;
 744                                if (uart_handle_break(port))
 745                                        continue;
 746                        }
 747
 748                        if (!(port->read_status_mask & UART_SR_RX_BREAK))
 749                                flag = TTY_NORMAL;
 750
 751                        spin_unlock(&port->lock);
 752                        sysrq = uart_handle_sysrq_char(port, buf[i]);
 753                        spin_lock(&port->lock);
 754                        if (!sysrq)
 755                                tty_insert_flip_char(tport, buf[i], flag);
 756                }
 757                count -= r_count;
 758        }
 759
 760        spin_unlock(&port->lock);
 761        tty_flip_buffer_push(tport);
 762        spin_lock(&port->lock);
 763
 764        if (misr & (UART_IMR_RXSTALE))
 765                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 766        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
 767        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 768
 769        /* Try to use DMA */
 770        msm_start_rx_dma(msm_port);
 771}
 772
 773static void msm_handle_rx(struct uart_port *port)
 774{
 775        struct tty_port *tport = &port->state->port;
 776        unsigned int sr;
 777
 778        /*
 779         * Handle overrun. My understanding of the hardware is that overrun
 780         * is not tied to the RX buffer, so we handle the case out of band.
 781         */
 782        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 783                port->icount.overrun++;
 784                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 785                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 786        }
 787
 788        /* and now the main RX loop */
 789        while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
 790                unsigned int c;
 791                char flag = TTY_NORMAL;
 792                int sysrq;
 793
 794                c = msm_read(port, UART_RF);
 795
 796                if (sr & UART_SR_RX_BREAK) {
 797                        port->icount.brk++;
 798                        if (uart_handle_break(port))
 799                                continue;
 800                } else if (sr & UART_SR_PAR_FRAME_ERR) {
 801                        port->icount.frame++;
 802                } else {
 803                        port->icount.rx++;
 804                }
 805
 806                /* Mask conditions we're ignorning. */
 807                sr &= port->read_status_mask;
 808
 809                if (sr & UART_SR_RX_BREAK)
 810                        flag = TTY_BREAK;
 811                else if (sr & UART_SR_PAR_FRAME_ERR)
 812                        flag = TTY_FRAME;
 813
 814                spin_unlock(&port->lock);
 815                sysrq = uart_handle_sysrq_char(port, c);
 816                spin_lock(&port->lock);
 817                if (!sysrq)
 818                        tty_insert_flip_char(tport, c, flag);
 819        }
 820
 821        spin_unlock(&port->lock);
 822        tty_flip_buffer_push(tport);
 823        spin_lock(&port->lock);
 824}
 825
 826static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
 827{
 828        struct circ_buf *xmit = &port->state->xmit;
 829        struct msm_port *msm_port = UART_TO_MSM(port);
 830        unsigned int num_chars;
 831        unsigned int tf_pointer = 0;
 832        void __iomem *tf;
 833
 834        if (msm_port->is_uartdm)
 835                tf = port->membase + UARTDM_TF;
 836        else
 837                tf = port->membase + UART_TF;
 838
 839        if (tx_count && msm_port->is_uartdm)
 840                msm_reset_dm_count(port, tx_count);
 841
 842        while (tf_pointer < tx_count) {
 843                int i;
 844                char buf[4] = { 0 };
 845
 846                if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
 847                        break;
 848
 849                if (msm_port->is_uartdm)
 850                        num_chars = min(tx_count - tf_pointer,
 851                                        (unsigned int)sizeof(buf));
 852                else
 853                        num_chars = 1;
 854
 855                for (i = 0; i < num_chars; i++) {
 856                        buf[i] = xmit->buf[xmit->tail + i];
 857                        port->icount.tx++;
 858                }
 859
 860                iowrite32_rep(tf, buf, 1);
 861                xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
 862                tf_pointer += num_chars;
 863        }
 864
 865        /* disable tx interrupts if nothing more to send */
 866        if (uart_circ_empty(xmit))
 867                msm_stop_tx(port);
 868
 869        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 870                uart_write_wakeup(port);
 871}
 872
 873static void msm_handle_tx(struct uart_port *port)
 874{
 875        struct msm_port *msm_port = UART_TO_MSM(port);
 876        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 877        struct msm_dma *dma = &msm_port->tx_dma;
 878        unsigned int pio_count, dma_count, dma_min;
 879        char buf[4] = { 0 };
 880        void __iomem *tf;
 881        int err = 0;
 882
 883        if (port->x_char) {
 884                if (msm_port->is_uartdm)
 885                        tf = port->membase + UARTDM_TF;
 886                else
 887                        tf = port->membase + UART_TF;
 888
 889                buf[0] = port->x_char;
 890
 891                if (msm_port->is_uartdm)
 892                        msm_reset_dm_count(port, 1);
 893
 894                iowrite32_rep(tf, buf, 1);
 895                port->icount.tx++;
 896                port->x_char = 0;
 897                return;
 898        }
 899
 900        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 901                msm_stop_tx(port);
 902                return;
 903        }
 904
 905        pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 906        dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 907
 908        dma_min = 1;    /* Always DMA */
 909        if (msm_port->is_uartdm > UARTDM_1P3) {
 910                dma_count = UARTDM_TX_AIGN(dma_count);
 911                dma_min = UARTDM_BURST_SIZE;
 912        } else {
 913                if (dma_count > UARTDM_TX_MAX)
 914                        dma_count = UARTDM_TX_MAX;
 915        }
 916
 917        if (pio_count > port->fifosize)
 918                pio_count = port->fifosize;
 919
 920        if (!dma->chan || dma_count < dma_min)
 921                msm_handle_tx_pio(port, pio_count);
 922        else
 923                err = msm_handle_tx_dma(msm_port, dma_count);
 924
 925        if (err)        /* fall back to PIO mode */
 926                msm_handle_tx_pio(port, pio_count);
 927}
 928
 929static void msm_handle_delta_cts(struct uart_port *port)
 930{
 931        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 932        port->icount.cts++;
 933        wake_up_interruptible(&port->state->port.delta_msr_wait);
 934}
 935
 936static irqreturn_t msm_uart_irq(int irq, void *dev_id)
 937{
 938        struct uart_port *port = dev_id;
 939        struct msm_port *msm_port = UART_TO_MSM(port);
 940        struct msm_dma *dma = &msm_port->rx_dma;
 941        unsigned long flags;
 942        unsigned int misr;
 943        u32 val;
 944
 945        spin_lock_irqsave(&port->lock, flags);
 946        misr = msm_read(port, UART_MISR);
 947        msm_write(port, 0, UART_IMR); /* disable interrupt */
 948
 949        if (misr & UART_IMR_RXBREAK_START) {
 950                msm_port->break_detected = true;
 951                msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
 952        }
 953
 954        if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
 955                if (dma->count) {
 956                        val = UART_CR_CMD_STALE_EVENT_DISABLE;
 957                        msm_write(port, val, UART_CR);
 958                        val = UART_CR_CMD_RESET_STALE_INT;
 959                        msm_write(port, val, UART_CR);
 960                        /*
 961                         * Flush DMA input fifo to memory, this will also
 962                         * trigger DMA RX completion
 963                         */
 964                        dmaengine_terminate_all(dma->chan);
 965                } else if (msm_port->is_uartdm) {
 966                        msm_handle_rx_dm(port, misr);
 967                } else {
 968                        msm_handle_rx(port);
 969                }
 970        }
 971        if (misr & UART_IMR_TXLEV)
 972                msm_handle_tx(port);
 973        if (misr & UART_IMR_DELTA_CTS)
 974                msm_handle_delta_cts(port);
 975
 976        msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
 977        spin_unlock_irqrestore(&port->lock, flags);
 978
 979        return IRQ_HANDLED;
 980}
 981
 982static unsigned int msm_tx_empty(struct uart_port *port)
 983{
 984        return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
 985}
 986
 987static unsigned int msm_get_mctrl(struct uart_port *port)
 988{
 989        return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 990}
 991
 992static void msm_reset(struct uart_port *port)
 993{
 994        struct msm_port *msm_port = UART_TO_MSM(port);
 995        unsigned int mr;
 996
 997        /* reset everything */
 998        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
 999        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
1000        msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
1001        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
1002        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
1003        msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1004        mr = msm_read(port, UART_MR1);
1005        mr &= ~UART_MR1_RX_RDY_CTL;
1006        msm_write(port, mr, UART_MR1);
1007
1008        /* Disable DM modes */
1009        if (msm_port->is_uartdm)
1010                msm_write(port, 0, UARTDM_DMEN);
1011}
1012
1013static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
1014{
1015        unsigned int mr;
1016
1017        mr = msm_read(port, UART_MR1);
1018
1019        if (!(mctrl & TIOCM_RTS)) {
1020                mr &= ~UART_MR1_RX_RDY_CTL;
1021                msm_write(port, mr, UART_MR1);
1022                msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1023        } else {
1024                mr |= UART_MR1_RX_RDY_CTL;
1025                msm_write(port, mr, UART_MR1);
1026        }
1027}
1028
1029static void msm_break_ctl(struct uart_port *port, int break_ctl)
1030{
1031        if (break_ctl)
1032                msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1033        else
1034                msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1035}
1036
1037struct msm_baud_map {
1038        u16     divisor;
1039        u8      code;
1040        u8      rxstale;
1041};
1042
1043static const struct msm_baud_map *
1044msm_find_best_baud(struct uart_port *port, unsigned int baud,
1045                   unsigned long *rate)
1046{
1047        struct msm_port *msm_port = UART_TO_MSM(port);
1048        unsigned int divisor, result;
1049        unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1050        const struct msm_baud_map *entry, *end, *best;
1051        static const struct msm_baud_map table[] = {
1052                {    1, 0xff, 31 },
1053                {    2, 0xee, 16 },
1054                {    3, 0xdd,  8 },
1055                {    4, 0xcc,  6 },
1056                {    6, 0xbb,  6 },
1057                {    8, 0xaa,  6 },
1058                {   12, 0x99,  6 },
1059                {   16, 0x88,  1 },
1060                {   24, 0x77,  1 },
1061                {   32, 0x66,  1 },
1062                {   48, 0x55,  1 },
1063                {   96, 0x44,  1 },
1064                {  192, 0x33,  1 },
1065                {  384, 0x22,  1 },
1066                {  768, 0x11,  1 },
1067                { 1536, 0x00,  1 },
1068        };
1069
1070        best = table; /* Default to smallest divider */
1071        target = clk_round_rate(msm_port->clk, 16 * baud);
1072        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1073
1074        end = table + ARRAY_SIZE(table);
1075        entry = table;
1076        while (entry < end) {
1077                if (entry->divisor <= divisor) {
1078                        result = target / entry->divisor / 16;
1079                        diff = abs(result - baud);
1080
1081                        /* Keep track of best entry */
1082                        if (diff < best_diff) {
1083                                best_diff = diff;
1084                                best = entry;
1085                                best_rate = target;
1086                        }
1087
1088                        if (result == baud)
1089                                break;
1090                } else if (entry->divisor > divisor) {
1091                        old = target;
1092                        target = clk_round_rate(msm_port->clk, old + 1);
1093                        /*
1094                         * The rate didn't get any faster so we can't do
1095                         * better at dividing it down
1096                         */
1097                        if (target == old)
1098                                break;
1099
1100                        /* Start the divisor search over at this new rate */
1101                        entry = table;
1102                        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1103                        continue;
1104                }
1105                entry++;
1106        }
1107
1108        *rate = best_rate;
1109        return best;
1110}
1111
1112static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1113                             unsigned long *saved_flags)
1114{
1115        unsigned int rxstale, watermark, mask;
1116        struct msm_port *msm_port = UART_TO_MSM(port);
1117        const struct msm_baud_map *entry;
1118        unsigned long flags, rate;
1119
1120        flags = *saved_flags;
1121        spin_unlock_irqrestore(&port->lock, flags);
1122
1123        entry = msm_find_best_baud(port, baud, &rate);
1124        clk_set_rate(msm_port->clk, rate);
1125        baud = rate / 16 / entry->divisor;
1126
1127        spin_lock_irqsave(&port->lock, flags);
1128        *saved_flags = flags;
1129        port->uartclk = rate;
1130
1131        msm_write(port, entry->code, UART_CSR);
1132
1133        /* RX stale watermark */
1134        rxstale = entry->rxstale;
1135        watermark = UART_IPR_STALE_LSB & rxstale;
1136        if (msm_port->is_uartdm) {
1137                mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1138        } else {
1139                watermark |= UART_IPR_RXSTALE_LAST;
1140                mask = UART_IPR_STALE_TIMEOUT_MSB;
1141        }
1142
1143        watermark |= mask & (rxstale << 2);
1144
1145        msm_write(port, watermark, UART_IPR);
1146
1147        /* set RX watermark */
1148        watermark = (port->fifosize * 3) / 4;
1149        msm_write(port, watermark, UART_RFWR);
1150
1151        /* set TX watermark */
1152        msm_write(port, 10, UART_TFWR);
1153
1154        msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1155        msm_reset(port);
1156
1157        /* Enable RX and TX */
1158        msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1159
1160        /* turn on RX and CTS interrupts */
1161        msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1162                        UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1163
1164        msm_write(port, msm_port->imr, UART_IMR);
1165
1166        if (msm_port->is_uartdm) {
1167                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1168                msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1169                msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1170        }
1171
1172        return baud;
1173}
1174
1175static void msm_init_clock(struct uart_port *port)
1176{
1177        struct msm_port *msm_port = UART_TO_MSM(port);
1178
1179        clk_prepare_enable(msm_port->clk);
1180        clk_prepare_enable(msm_port->pclk);
1181        msm_serial_set_mnd_regs(port);
1182}
1183
1184static int msm_startup(struct uart_port *port)
1185{
1186        struct msm_port *msm_port = UART_TO_MSM(port);
1187        unsigned int data, rfr_level, mask;
1188        int ret;
1189
1190        snprintf(msm_port->name, sizeof(msm_port->name),
1191                 "msm_serial%d", port->line);
1192
1193        msm_init_clock(port);
1194
1195        if (likely(port->fifosize > 12))
1196                rfr_level = port->fifosize - 12;
1197        else
1198                rfr_level = port->fifosize;
1199
1200        /* set automatic RFR level */
1201        data = msm_read(port, UART_MR1);
1202
1203        if (msm_port->is_uartdm)
1204                mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1205        else
1206                mask = UART_MR1_AUTO_RFR_LEVEL1;
1207
1208        data &= ~mask;
1209        data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1210        data |= mask & (rfr_level << 2);
1211        data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1212        msm_write(port, data, UART_MR1);
1213
1214        if (msm_port->is_uartdm) {
1215                msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1216                msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1217        }
1218
1219        ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1220                          msm_port->name, port);
1221        if (unlikely(ret))
1222                goto err_irq;
1223
1224        return 0;
1225
1226err_irq:
1227        if (msm_port->is_uartdm)
1228                msm_release_dma(msm_port);
1229
1230        clk_disable_unprepare(msm_port->pclk);
1231        clk_disable_unprepare(msm_port->clk);
1232
1233        return ret;
1234}
1235
1236static void msm_shutdown(struct uart_port *port)
1237{
1238        struct msm_port *msm_port = UART_TO_MSM(port);
1239
1240        msm_port->imr = 0;
1241        msm_write(port, 0, UART_IMR); /* disable interrupts */
1242
1243        if (msm_port->is_uartdm)
1244                msm_release_dma(msm_port);
1245
1246        clk_disable_unprepare(msm_port->clk);
1247
1248        free_irq(port->irq, port);
1249}
1250
1251static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1252                            struct ktermios *old)
1253{
1254        struct msm_port *msm_port = UART_TO_MSM(port);
1255        struct msm_dma *dma = &msm_port->rx_dma;
1256        unsigned long flags;
1257        unsigned int baud, mr;
1258
1259        spin_lock_irqsave(&port->lock, flags);
1260
1261        if (dma->chan) /* Terminate if any */
1262                msm_stop_dma(port, dma);
1263
1264        /* calculate and set baud rate */
1265        baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1266        baud = msm_set_baud_rate(port, baud, &flags);
1267        if (tty_termios_baud_rate(termios))
1268                tty_termios_encode_baud_rate(termios, baud, baud);
1269
1270        /* calculate parity */
1271        mr = msm_read(port, UART_MR2);
1272        mr &= ~UART_MR2_PARITY_MODE;
1273        if (termios->c_cflag & PARENB) {
1274                if (termios->c_cflag & PARODD)
1275                        mr |= UART_MR2_PARITY_MODE_ODD;
1276                else if (termios->c_cflag & CMSPAR)
1277                        mr |= UART_MR2_PARITY_MODE_SPACE;
1278                else
1279                        mr |= UART_MR2_PARITY_MODE_EVEN;
1280        }
1281
1282        /* calculate bits per char */
1283        mr &= ~UART_MR2_BITS_PER_CHAR;
1284        switch (termios->c_cflag & CSIZE) {
1285        case CS5:
1286                mr |= UART_MR2_BITS_PER_CHAR_5;
1287                break;
1288        case CS6:
1289                mr |= UART_MR2_BITS_PER_CHAR_6;
1290                break;
1291        case CS7:
1292                mr |= UART_MR2_BITS_PER_CHAR_7;
1293                break;
1294        case CS8:
1295        default:
1296                mr |= UART_MR2_BITS_PER_CHAR_8;
1297                break;
1298        }
1299
1300        /* calculate stop bits */
1301        mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1302        if (termios->c_cflag & CSTOPB)
1303                mr |= UART_MR2_STOP_BIT_LEN_TWO;
1304        else
1305                mr |= UART_MR2_STOP_BIT_LEN_ONE;
1306
1307        /* set parity, bits per char, and stop bit */
1308        msm_write(port, mr, UART_MR2);
1309
1310        /* calculate and set hardware flow control */
1311        mr = msm_read(port, UART_MR1);
1312        mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1313        if (termios->c_cflag & CRTSCTS) {
1314                mr |= UART_MR1_CTS_CTL;
1315                mr |= UART_MR1_RX_RDY_CTL;
1316        }
1317        msm_write(port, mr, UART_MR1);
1318
1319        /* Configure status bits to ignore based on termio flags. */
1320        port->read_status_mask = 0;
1321        if (termios->c_iflag & INPCK)
1322                port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1323        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1324                port->read_status_mask |= UART_SR_RX_BREAK;
1325
1326        uart_update_timeout(port, termios->c_cflag, baud);
1327
1328        /* Try to use DMA */
1329        msm_start_rx_dma(msm_port);
1330
1331        spin_unlock_irqrestore(&port->lock, flags);
1332}
1333
1334static const char *msm_type(struct uart_port *port)
1335{
1336        return "MSM";
1337}
1338
1339static void msm_release_port(struct uart_port *port)
1340{
1341        struct platform_device *pdev = to_platform_device(port->dev);
1342        struct resource *uart_resource;
1343        resource_size_t size;
1344
1345        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1346        if (unlikely(!uart_resource))
1347                return;
1348        size = resource_size(uart_resource);
1349
1350        release_mem_region(port->mapbase, size);
1351        iounmap(port->membase);
1352        port->membase = NULL;
1353}
1354
1355static int msm_request_port(struct uart_port *port)
1356{
1357        struct platform_device *pdev = to_platform_device(port->dev);
1358        struct resource *uart_resource;
1359        resource_size_t size;
1360        int ret;
1361
1362        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1363        if (unlikely(!uart_resource))
1364                return -ENXIO;
1365
1366        size = resource_size(uart_resource);
1367
1368        if (!request_mem_region(port->mapbase, size, "msm_serial"))
1369                return -EBUSY;
1370
1371        port->membase = ioremap(port->mapbase, size);
1372        if (!port->membase) {
1373                ret = -EBUSY;
1374                goto fail_release_port;
1375        }
1376
1377        return 0;
1378
1379fail_release_port:
1380        release_mem_region(port->mapbase, size);
1381        return ret;
1382}
1383
1384static void msm_config_port(struct uart_port *port, int flags)
1385{
1386        int ret;
1387
1388        if (flags & UART_CONFIG_TYPE) {
1389                port->type = PORT_MSM;
1390                ret = msm_request_port(port);
1391                if (ret)
1392                        return;
1393        }
1394}
1395
1396static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1397{
1398        if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1399                return -EINVAL;
1400        if (unlikely(port->irq != ser->irq))
1401                return -EINVAL;
1402        return 0;
1403}
1404
1405static void msm_power(struct uart_port *port, unsigned int state,
1406                      unsigned int oldstate)
1407{
1408        struct msm_port *msm_port = UART_TO_MSM(port);
1409
1410        switch (state) {
1411        case 0:
1412                clk_prepare_enable(msm_port->clk);
1413                clk_prepare_enable(msm_port->pclk);
1414                break;
1415        case 3:
1416                clk_disable_unprepare(msm_port->clk);
1417                clk_disable_unprepare(msm_port->pclk);
1418                break;
1419        default:
1420                pr_err("msm_serial: Unknown PM state %d\n", state);
1421        }
1422}
1423
1424#ifdef CONFIG_CONSOLE_POLL
1425static int msm_poll_get_char_single(struct uart_port *port)
1426{
1427        struct msm_port *msm_port = UART_TO_MSM(port);
1428        unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1429
1430        if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1431                return NO_POLL_CHAR;
1432
1433        return msm_read(port, rf_reg) & 0xff;
1434}
1435
1436static int msm_poll_get_char_dm(struct uart_port *port)
1437{
1438        int c;
1439        static u32 slop;
1440        static int count;
1441        unsigned char *sp = (unsigned char *)&slop;
1442
1443        /* Check if a previous read had more than one char */
1444        if (count) {
1445                c = sp[sizeof(slop) - count];
1446                count--;
1447        /* Or if FIFO is empty */
1448        } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1449                /*
1450                 * If RX packing buffer has less than a word, force stale to
1451                 * push contents into RX FIFO
1452                 */
1453                count = msm_read(port, UARTDM_RXFS);
1454                count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1455                if (count) {
1456                        msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1457                        slop = msm_read(port, UARTDM_RF);
1458                        c = sp[0];
1459                        count--;
1460                        msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1461                        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1462                        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1463                                  UART_CR);
1464                } else {
1465                        c = NO_POLL_CHAR;
1466                }
1467        /* FIFO has a word */
1468        } else {
1469                slop = msm_read(port, UARTDM_RF);
1470                c = sp[0];
1471                count = sizeof(slop) - 1;
1472        }
1473
1474        return c;
1475}
1476
1477static int msm_poll_get_char(struct uart_port *port)
1478{
1479        u32 imr;
1480        int c;
1481        struct msm_port *msm_port = UART_TO_MSM(port);
1482
1483        /* Disable all interrupts */
1484        imr = msm_read(port, UART_IMR);
1485        msm_write(port, 0, UART_IMR);
1486
1487        if (msm_port->is_uartdm)
1488                c = msm_poll_get_char_dm(port);
1489        else
1490                c = msm_poll_get_char_single(port);
1491
1492        /* Enable interrupts */
1493        msm_write(port, imr, UART_IMR);
1494
1495        return c;
1496}
1497
1498static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1499{
1500        u32 imr;
1501        struct msm_port *msm_port = UART_TO_MSM(port);
1502
1503        /* Disable all interrupts */
1504        imr = msm_read(port, UART_IMR);
1505        msm_write(port, 0, UART_IMR);
1506
1507        if (msm_port->is_uartdm)
1508                msm_reset_dm_count(port, 1);
1509
1510        /* Wait until FIFO is empty */
1511        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1512                cpu_relax();
1513
1514        /* Write a character */
1515        msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1516
1517        /* Wait until FIFO is empty */
1518        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1519                cpu_relax();
1520
1521        /* Enable interrupts */
1522        msm_write(port, imr, UART_IMR);
1523}
1524#endif
1525
1526static struct uart_ops msm_uart_pops = {
1527        .tx_empty = msm_tx_empty,
1528        .set_mctrl = msm_set_mctrl,
1529        .get_mctrl = msm_get_mctrl,
1530        .stop_tx = msm_stop_tx,
1531        .start_tx = msm_start_tx,
1532        .stop_rx = msm_stop_rx,
1533        .enable_ms = msm_enable_ms,
1534        .break_ctl = msm_break_ctl,
1535        .startup = msm_startup,
1536        .shutdown = msm_shutdown,
1537        .set_termios = msm_set_termios,
1538        .type = msm_type,
1539        .release_port = msm_release_port,
1540        .request_port = msm_request_port,
1541        .config_port = msm_config_port,
1542        .verify_port = msm_verify_port,
1543        .pm = msm_power,
1544#ifdef CONFIG_CONSOLE_POLL
1545        .poll_get_char  = msm_poll_get_char,
1546        .poll_put_char  = msm_poll_put_char,
1547#endif
1548};
1549
1550static struct msm_port msm_uart_ports[] = {
1551        {
1552                .uart = {
1553                        .iotype = UPIO_MEM,
1554                        .ops = &msm_uart_pops,
1555                        .flags = UPF_BOOT_AUTOCONF,
1556                        .fifosize = 64,
1557                        .line = 0,
1558                },
1559        },
1560        {
1561                .uart = {
1562                        .iotype = UPIO_MEM,
1563                        .ops = &msm_uart_pops,
1564                        .flags = UPF_BOOT_AUTOCONF,
1565                        .fifosize = 64,
1566                        .line = 1,
1567                },
1568        },
1569        {
1570                .uart = {
1571                        .iotype = UPIO_MEM,
1572                        .ops = &msm_uart_pops,
1573                        .flags = UPF_BOOT_AUTOCONF,
1574                        .fifosize = 64,
1575                        .line = 2,
1576                },
1577        },
1578};
1579
1580#define UART_NR ARRAY_SIZE(msm_uart_ports)
1581
1582static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1583{
1584        return &msm_uart_ports[line].uart;
1585}
1586
1587#ifdef CONFIG_SERIAL_MSM_CONSOLE
1588static void __msm_console_write(struct uart_port *port, const char *s,
1589                                unsigned int count, bool is_uartdm)
1590{
1591        int i;
1592        int num_newlines = 0;
1593        bool replaced = false;
1594        void __iomem *tf;
1595        int locked = 1;
1596
1597        if (is_uartdm)
1598                tf = port->membase + UARTDM_TF;
1599        else
1600                tf = port->membase + UART_TF;
1601
1602        /* Account for newlines that will get a carriage return added */
1603        for (i = 0; i < count; i++)
1604                if (s[i] == '\n')
1605                        num_newlines++;
1606        count += num_newlines;
1607
1608        if (port->sysrq)
1609                locked = 0;
1610        else if (oops_in_progress)
1611                locked = spin_trylock(&port->lock);
1612        else
1613                spin_lock(&port->lock);
1614
1615        if (is_uartdm)
1616                msm_reset_dm_count(port, count);
1617
1618        i = 0;
1619        while (i < count) {
1620                int j;
1621                unsigned int num_chars;
1622                char buf[4] = { 0 };
1623
1624                if (is_uartdm)
1625                        num_chars = min(count - i, (unsigned int)sizeof(buf));
1626                else
1627                        num_chars = 1;
1628
1629                for (j = 0; j < num_chars; j++) {
1630                        char c = *s;
1631
1632                        if (c == '\n' && !replaced) {
1633                                buf[j] = '\r';
1634                                j++;
1635                                replaced = true;
1636                        }
1637                        if (j < num_chars) {
1638                                buf[j] = c;
1639                                s++;
1640                                replaced = false;
1641                        }
1642                }
1643
1644                while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1645                        cpu_relax();
1646
1647                iowrite32_rep(tf, buf, 1);
1648                i += num_chars;
1649        }
1650
1651        if (locked)
1652                spin_unlock(&port->lock);
1653}
1654
1655static void msm_console_write(struct console *co, const char *s,
1656                              unsigned int count)
1657{
1658        struct uart_port *port;
1659        struct msm_port *msm_port;
1660
1661        BUG_ON(co->index < 0 || co->index >= UART_NR);
1662
1663        port = msm_get_port_from_line(co->index);
1664        msm_port = UART_TO_MSM(port);
1665
1666        __msm_console_write(port, s, count, msm_port->is_uartdm);
1667}
1668
1669static int msm_console_setup(struct console *co, char *options)
1670{
1671        struct uart_port *port;
1672        int baud = 115200;
1673        int bits = 8;
1674        int parity = 'n';
1675        int flow = 'n';
1676
1677        if (unlikely(co->index >= UART_NR || co->index < 0))
1678                return -ENXIO;
1679
1680        port = msm_get_port_from_line(co->index);
1681
1682        if (unlikely(!port->membase))
1683                return -ENXIO;
1684
1685        msm_init_clock(port);
1686
1687        if (options)
1688                uart_parse_options(options, &baud, &parity, &bits, &flow);
1689
1690        pr_info("msm_serial: console setup on port #%d\n", port->line);
1691
1692        return uart_set_options(port, co, baud, parity, bits, flow);
1693}
1694
1695static void
1696msm_serial_early_write(struct console *con, const char *s, unsigned n)
1697{
1698        struct earlycon_device *dev = con->data;
1699
1700        __msm_console_write(&dev->port, s, n, false);
1701}
1702
1703static int __init
1704msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1705{
1706        if (!device->port.membase)
1707                return -ENODEV;
1708
1709        device->con->write = msm_serial_early_write;
1710        return 0;
1711}
1712OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1713                    msm_serial_early_console_setup);
1714
1715static void
1716msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1717{
1718        struct earlycon_device *dev = con->data;
1719
1720        __msm_console_write(&dev->port, s, n, true);
1721}
1722
1723static int __init
1724msm_serial_early_console_setup_dm(struct earlycon_device *device,
1725                                  const char *opt)
1726{
1727        if (!device->port.membase)
1728                return -ENODEV;
1729
1730        device->con->write = msm_serial_early_write_dm;
1731        return 0;
1732}
1733OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1734                    msm_serial_early_console_setup_dm);
1735
1736static struct uart_driver msm_uart_driver;
1737
1738static struct console msm_console = {
1739        .name = "ttyMSM",
1740        .write = msm_console_write,
1741        .device = uart_console_device,
1742        .setup = msm_console_setup,
1743        .flags = CON_PRINTBUFFER,
1744        .index = -1,
1745        .data = &msm_uart_driver,
1746};
1747
1748#define MSM_CONSOLE     (&msm_console)
1749
1750#else
1751#define MSM_CONSOLE     NULL
1752#endif
1753
1754static struct uart_driver msm_uart_driver = {
1755        .owner = THIS_MODULE,
1756        .driver_name = "msm_serial",
1757        .dev_name = "ttyMSM",
1758        .nr = UART_NR,
1759        .cons = MSM_CONSOLE,
1760};
1761
1762static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1763
1764static const struct of_device_id msm_uartdm_table[] = {
1765        { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1766        { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1767        { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1768        { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1769        { }
1770};
1771
1772static int msm_serial_probe(struct platform_device *pdev)
1773{
1774        struct msm_port *msm_port;
1775        struct resource *resource;
1776        struct uart_port *port;
1777        const struct of_device_id *id;
1778        int irq, line;
1779
1780        if (pdev->dev.of_node)
1781                line = of_alias_get_id(pdev->dev.of_node, "serial");
1782        else
1783                line = pdev->id;
1784
1785        if (line < 0)
1786                line = atomic_inc_return(&msm_uart_next_id) - 1;
1787
1788        if (unlikely(line < 0 || line >= UART_NR))
1789                return -ENXIO;
1790
1791        dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1792
1793        port = msm_get_port_from_line(line);
1794        port->dev = &pdev->dev;
1795        msm_port = UART_TO_MSM(port);
1796
1797        id = of_match_device(msm_uartdm_table, &pdev->dev);
1798        if (id)
1799                msm_port->is_uartdm = (unsigned long)id->data;
1800        else
1801                msm_port->is_uartdm = 0;
1802
1803        msm_port->clk = devm_clk_get(&pdev->dev, "core");
1804        if (IS_ERR(msm_port->clk))
1805                return PTR_ERR(msm_port->clk);
1806
1807        if (msm_port->is_uartdm) {
1808                msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1809                if (IS_ERR(msm_port->pclk))
1810                        return PTR_ERR(msm_port->pclk);
1811        }
1812
1813        port->uartclk = clk_get_rate(msm_port->clk);
1814        dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1815
1816        resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1817        if (unlikely(!resource))
1818                return -ENXIO;
1819        port->mapbase = resource->start;
1820
1821        irq = platform_get_irq(pdev, 0);
1822        if (unlikely(irq < 0))
1823                return -ENXIO;
1824        port->irq = irq;
1825        port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MSM_CONSOLE);
1826
1827        platform_set_drvdata(pdev, port);
1828
1829        return uart_add_one_port(&msm_uart_driver, port);
1830}
1831
1832static int msm_serial_remove(struct platform_device *pdev)
1833{
1834        struct uart_port *port = platform_get_drvdata(pdev);
1835
1836        uart_remove_one_port(&msm_uart_driver, port);
1837
1838        return 0;
1839}
1840
1841static const struct of_device_id msm_match_table[] = {
1842        { .compatible = "qcom,msm-uart" },
1843        { .compatible = "qcom,msm-uartdm" },
1844        {}
1845};
1846MODULE_DEVICE_TABLE(of, msm_match_table);
1847
1848static int __maybe_unused msm_serial_suspend(struct device *dev)
1849{
1850        struct msm_port *port = dev_get_drvdata(dev);
1851
1852        uart_suspend_port(&msm_uart_driver, &port->uart);
1853
1854        return 0;
1855}
1856
1857static int __maybe_unused msm_serial_resume(struct device *dev)
1858{
1859        struct msm_port *port = dev_get_drvdata(dev);
1860
1861        uart_resume_port(&msm_uart_driver, &port->uart);
1862
1863        return 0;
1864}
1865
1866static const struct dev_pm_ops msm_serial_dev_pm_ops = {
1867        SET_SYSTEM_SLEEP_PM_OPS(msm_serial_suspend, msm_serial_resume)
1868};
1869
1870static struct platform_driver msm_platform_driver = {
1871        .remove = msm_serial_remove,
1872        .probe = msm_serial_probe,
1873        .driver = {
1874                .name = "msm_serial",
1875                .pm = &msm_serial_dev_pm_ops,
1876                .of_match_table = msm_match_table,
1877        },
1878};
1879
1880static int __init msm_serial_init(void)
1881{
1882        int ret;
1883
1884        ret = uart_register_driver(&msm_uart_driver);
1885        if (unlikely(ret))
1886                return ret;
1887
1888        ret = platform_driver_register(&msm_platform_driver);
1889        if (unlikely(ret))
1890                uart_unregister_driver(&msm_uart_driver);
1891
1892        pr_info("msm_serial: driver initialized\n");
1893
1894        return ret;
1895}
1896
1897static void __exit msm_serial_exit(void)
1898{
1899        platform_driver_unregister(&msm_platform_driver);
1900        uart_unregister_driver(&msm_uart_driver);
1901}
1902
1903module_init(msm_serial_init);
1904module_exit(msm_serial_exit);
1905
1906MODULE_AUTHOR("Robert Love <rlove@google.com>");
1907MODULE_DESCRIPTION("Driver for msm7x serial device");
1908MODULE_LICENSE("GPL");
1909