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        unsigned long flags;
 430        unsigned int count;
 431        u32 val;
 432
 433        spin_lock_irqsave(&port->lock, flags);
 434
 435        /* Already stopped */
 436        if (!dma->count)
 437                goto done;
 438
 439        dmaengine_tx_status(dma->chan, dma->cookie, &state);
 440
 441        dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
 442
 443        val = msm_read(port, UARTDM_DMEN);
 444        val &= ~dma->enable_bit;
 445        msm_write(port, val, UARTDM_DMEN);
 446
 447        if (msm_port->is_uartdm > UARTDM_1P3) {
 448                msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 449                msm_write(port, UART_CR_TX_ENABLE, UART_CR);
 450        }
 451
 452        count = dma->count - state.residue;
 453        port->icount.tx += count;
 454        dma->count = 0;
 455
 456        xmit->tail += count;
 457        xmit->tail &= UART_XMIT_SIZE - 1;
 458
 459        /* Restore "Tx FIFO below watermark" interrupt */
 460        msm_port->imr |= UART_IMR_TXLEV;
 461        msm_write(port, msm_port->imr, UART_IMR);
 462
 463        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 464                uart_write_wakeup(port);
 465
 466        msm_handle_tx(port);
 467done:
 468        spin_unlock_irqrestore(&port->lock, flags);
 469}
 470
 471static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
 472{
 473        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 474        struct uart_port *port = &msm_port->uart;
 475        struct msm_dma *dma = &msm_port->tx_dma;
 476        void *cpu_addr;
 477        int ret;
 478        u32 val;
 479
 480        cpu_addr = &xmit->buf[xmit->tail];
 481
 482        dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
 483        ret = dma_mapping_error(port->dev, dma->phys);
 484        if (ret)
 485                return ret;
 486
 487        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 488                                                count, DMA_MEM_TO_DEV,
 489                                                DMA_PREP_INTERRUPT |
 490                                                DMA_PREP_FENCE);
 491        if (!dma->desc) {
 492                ret = -EIO;
 493                goto unmap;
 494        }
 495
 496        dma->desc->callback = msm_complete_tx_dma;
 497        dma->desc->callback_param = msm_port;
 498
 499        dma->cookie = dmaengine_submit(dma->desc);
 500        ret = dma_submit_error(dma->cookie);
 501        if (ret)
 502                goto unmap;
 503
 504        /*
 505         * Using DMA complete for Tx FIFO reload, no need for
 506         * "Tx FIFO below watermark" one, disable it
 507         */
 508        msm_port->imr &= ~UART_IMR_TXLEV;
 509        msm_write(port, msm_port->imr, UART_IMR);
 510
 511        dma->count = count;
 512
 513        val = msm_read(port, UARTDM_DMEN);
 514        val |= dma->enable_bit;
 515
 516        if (msm_port->is_uartdm < UARTDM_1P4)
 517                msm_write(port, val, UARTDM_DMEN);
 518
 519        msm_reset_dm_count(port, count);
 520
 521        if (msm_port->is_uartdm > UARTDM_1P3)
 522                msm_write(port, val, UARTDM_DMEN);
 523
 524        dma_async_issue_pending(dma->chan);
 525        return 0;
 526unmap:
 527        dma_unmap_single(port->dev, dma->phys, count, dma->dir);
 528        return ret;
 529}
 530
 531static void msm_complete_rx_dma(void *args)
 532{
 533        struct msm_port *msm_port = args;
 534        struct uart_port *port = &msm_port->uart;
 535        struct tty_port *tport = &port->state->port;
 536        struct msm_dma *dma = &msm_port->rx_dma;
 537        int count = 0, i, sysrq;
 538        unsigned long flags;
 539        u32 val;
 540
 541        spin_lock_irqsave(&port->lock, flags);
 542
 543        /* Already stopped */
 544        if (!dma->count)
 545                goto done;
 546
 547        val = msm_read(port, UARTDM_DMEN);
 548        val &= ~dma->enable_bit;
 549        msm_write(port, val, UARTDM_DMEN);
 550
 551        if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
 552                port->icount.overrun++;
 553                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 554                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 555        }
 556
 557        count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
 558
 559        port->icount.rx += count;
 560
 561        dma->count = 0;
 562
 563        dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 564
 565        for (i = 0; i < count; i++) {
 566                char flag = TTY_NORMAL;
 567
 568                if (msm_port->break_detected && dma->virt[i] == 0) {
 569                        port->icount.brk++;
 570                        flag = TTY_BREAK;
 571                        msm_port->break_detected = false;
 572                        if (uart_handle_break(port))
 573                                continue;
 574                }
 575
 576                if (!(port->read_status_mask & UART_SR_RX_BREAK))
 577                        flag = TTY_NORMAL;
 578
 579                spin_unlock_irqrestore(&port->lock, flags);
 580                sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
 581                spin_lock_irqsave(&port->lock, flags);
 582                if (!sysrq)
 583                        tty_insert_flip_char(tport, dma->virt[i], flag);
 584        }
 585
 586        msm_start_rx_dma(msm_port);
 587done:
 588        spin_unlock_irqrestore(&port->lock, flags);
 589
 590        if (count)
 591                tty_flip_buffer_push(tport);
 592}
 593
 594static void msm_start_rx_dma(struct msm_port *msm_port)
 595{
 596        struct msm_dma *dma = &msm_port->rx_dma;
 597        struct uart_port *uart = &msm_port->uart;
 598        u32 val;
 599        int ret;
 600
 601        if (!dma->chan)
 602                return;
 603
 604        dma->phys = dma_map_single(uart->dev, dma->virt,
 605                                   UARTDM_RX_SIZE, dma->dir);
 606        ret = dma_mapping_error(uart->dev, dma->phys);
 607        if (ret)
 608                goto sw_mode;
 609
 610        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 611                                                UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
 612                                                DMA_PREP_INTERRUPT);
 613        if (!dma->desc)
 614                goto unmap;
 615
 616        dma->desc->callback = msm_complete_rx_dma;
 617        dma->desc->callback_param = msm_port;
 618
 619        dma->cookie = dmaengine_submit(dma->desc);
 620        ret = dma_submit_error(dma->cookie);
 621        if (ret)
 622                goto unmap;
 623        /*
 624         * Using DMA for FIFO off-load, no need for "Rx FIFO over
 625         * watermark" or "stale" interrupts, disable them
 626         */
 627        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 628
 629        /*
 630         * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
 631         * we need RXSTALE to flush input DMA fifo to memory
 632         */
 633        if (msm_port->is_uartdm < UARTDM_1P4)
 634                msm_port->imr |= UART_IMR_RXSTALE;
 635
 636        msm_write(uart, msm_port->imr, UART_IMR);
 637
 638        dma->count = UARTDM_RX_SIZE;
 639
 640        dma_async_issue_pending(dma->chan);
 641
 642        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 643        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 644
 645        val = msm_read(uart, UARTDM_DMEN);
 646        val |= dma->enable_bit;
 647
 648        if (msm_port->is_uartdm < UARTDM_1P4)
 649                msm_write(uart, val, UARTDM_DMEN);
 650
 651        msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
 652
 653        if (msm_port->is_uartdm > UARTDM_1P3)
 654                msm_write(uart, val, UARTDM_DMEN);
 655
 656        return;
 657unmap:
 658        dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 659
 660sw_mode:
 661        /*
 662         * Switch from DMA to SW/FIFO mode. After clearing Rx BAM (UARTDM_DMEN),
 663         * receiver must be reset.
 664         */
 665        msm_write(uart, UART_CR_CMD_RESET_RX, UART_CR);
 666        msm_write(uart, UART_CR_RX_ENABLE, UART_CR);
 667
 668        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 669        msm_write(uart, 0xFFFFFF, UARTDM_DMRX);
 670        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 671
 672        /* Re-enable RX interrupts */
 673        msm_port->imr |= (UART_IMR_RXLEV | UART_IMR_RXSTALE);
 674        msm_write(uart, msm_port->imr, UART_IMR);
 675}
 676
 677static void msm_stop_rx(struct uart_port *port)
 678{
 679        struct msm_port *msm_port = UART_TO_MSM(port);
 680        struct msm_dma *dma = &msm_port->rx_dma;
 681
 682        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 683        msm_write(port, msm_port->imr, UART_IMR);
 684
 685        if (dma->chan)
 686                msm_stop_dma(port, dma);
 687}
 688
 689static void msm_enable_ms(struct uart_port *port)
 690{
 691        struct msm_port *msm_port = UART_TO_MSM(port);
 692
 693        msm_port->imr |= UART_IMR_DELTA_CTS;
 694        msm_write(port, msm_port->imr, UART_IMR);
 695}
 696
 697static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
 698        __must_hold(&port->lock)
 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        tty_flip_buffer_push(tport);
 761
 762        if (misr & (UART_IMR_RXSTALE))
 763                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 764        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
 765        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 766
 767        /* Try to use DMA */
 768        msm_start_rx_dma(msm_port);
 769}
 770
 771static void msm_handle_rx(struct uart_port *port)
 772        __must_hold(&port->lock)
 773{
 774        struct tty_port *tport = &port->state->port;
 775        unsigned int sr;
 776
 777        /*
 778         * Handle overrun. My understanding of the hardware is that overrun
 779         * is not tied to the RX buffer, so we handle the case out of band.
 780         */
 781        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 782                port->icount.overrun++;
 783                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 784                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 785        }
 786
 787        /* and now the main RX loop */
 788        while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
 789                unsigned int c;
 790                char flag = TTY_NORMAL;
 791                int sysrq;
 792
 793                c = msm_read(port, UART_RF);
 794
 795                if (sr & UART_SR_RX_BREAK) {
 796                        port->icount.brk++;
 797                        if (uart_handle_break(port))
 798                                continue;
 799                } else if (sr & UART_SR_PAR_FRAME_ERR) {
 800                        port->icount.frame++;
 801                } else {
 802                        port->icount.rx++;
 803                }
 804
 805                /* Mask conditions we're ignorning. */
 806                sr &= port->read_status_mask;
 807
 808                if (sr & UART_SR_RX_BREAK)
 809                        flag = TTY_BREAK;
 810                else if (sr & UART_SR_PAR_FRAME_ERR)
 811                        flag = TTY_FRAME;
 812
 813                spin_unlock(&port->lock);
 814                sysrq = uart_handle_sysrq_char(port, c);
 815                spin_lock(&port->lock);
 816                if (!sysrq)
 817                        tty_insert_flip_char(tport, c, flag);
 818        }
 819
 820        tty_flip_buffer_push(tport);
 821}
 822
 823static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
 824{
 825        struct circ_buf *xmit = &port->state->xmit;
 826        struct msm_port *msm_port = UART_TO_MSM(port);
 827        unsigned int num_chars;
 828        unsigned int tf_pointer = 0;
 829        void __iomem *tf;
 830
 831        if (msm_port->is_uartdm)
 832                tf = port->membase + UARTDM_TF;
 833        else
 834                tf = port->membase + UART_TF;
 835
 836        if (tx_count && msm_port->is_uartdm)
 837                msm_reset_dm_count(port, tx_count);
 838
 839        while (tf_pointer < tx_count) {
 840                int i;
 841                char buf[4] = { 0 };
 842
 843                if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
 844                        break;
 845
 846                if (msm_port->is_uartdm)
 847                        num_chars = min(tx_count - tf_pointer,
 848                                        (unsigned int)sizeof(buf));
 849                else
 850                        num_chars = 1;
 851
 852                for (i = 0; i < num_chars; i++) {
 853                        buf[i] = xmit->buf[xmit->tail + i];
 854                        port->icount.tx++;
 855                }
 856
 857                iowrite32_rep(tf, buf, 1);
 858                xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
 859                tf_pointer += num_chars;
 860        }
 861
 862        /* disable tx interrupts if nothing more to send */
 863        if (uart_circ_empty(xmit))
 864                msm_stop_tx(port);
 865
 866        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 867                uart_write_wakeup(port);
 868}
 869
 870static void msm_handle_tx(struct uart_port *port)
 871{
 872        struct msm_port *msm_port = UART_TO_MSM(port);
 873        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 874        struct msm_dma *dma = &msm_port->tx_dma;
 875        unsigned int pio_count, dma_count, dma_min;
 876        char buf[4] = { 0 };
 877        void __iomem *tf;
 878        int err = 0;
 879
 880        if (port->x_char) {
 881                if (msm_port->is_uartdm)
 882                        tf = port->membase + UARTDM_TF;
 883                else
 884                        tf = port->membase + UART_TF;
 885
 886                buf[0] = port->x_char;
 887
 888                if (msm_port->is_uartdm)
 889                        msm_reset_dm_count(port, 1);
 890
 891                iowrite32_rep(tf, buf, 1);
 892                port->icount.tx++;
 893                port->x_char = 0;
 894                return;
 895        }
 896
 897        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 898                msm_stop_tx(port);
 899                return;
 900        }
 901
 902        pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 903        dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 904
 905        dma_min = 1;    /* Always DMA */
 906        if (msm_port->is_uartdm > UARTDM_1P3) {
 907                dma_count = UARTDM_TX_AIGN(dma_count);
 908                dma_min = UARTDM_BURST_SIZE;
 909        } else {
 910                if (dma_count > UARTDM_TX_MAX)
 911                        dma_count = UARTDM_TX_MAX;
 912        }
 913
 914        if (pio_count > port->fifosize)
 915                pio_count = port->fifosize;
 916
 917        if (!dma->chan || dma_count < dma_min)
 918                msm_handle_tx_pio(port, pio_count);
 919        else
 920                err = msm_handle_tx_dma(msm_port, dma_count);
 921
 922        if (err)        /* fall back to PIO mode */
 923                msm_handle_tx_pio(port, pio_count);
 924}
 925
 926static void msm_handle_delta_cts(struct uart_port *port)
 927{
 928        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 929        port->icount.cts++;
 930        wake_up_interruptible(&port->state->port.delta_msr_wait);
 931}
 932
 933static irqreturn_t msm_uart_irq(int irq, void *dev_id)
 934{
 935        struct uart_port *port = dev_id;
 936        struct msm_port *msm_port = UART_TO_MSM(port);
 937        struct msm_dma *dma = &msm_port->rx_dma;
 938        unsigned long flags;
 939        unsigned int misr;
 940        u32 val;
 941
 942        spin_lock_irqsave(&port->lock, flags);
 943        misr = msm_read(port, UART_MISR);
 944        msm_write(port, 0, UART_IMR); /* disable interrupt */
 945
 946        if (misr & UART_IMR_RXBREAK_START) {
 947                msm_port->break_detected = true;
 948                msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
 949        }
 950
 951        if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
 952                if (dma->count) {
 953                        val = UART_CR_CMD_STALE_EVENT_DISABLE;
 954                        msm_write(port, val, UART_CR);
 955                        val = UART_CR_CMD_RESET_STALE_INT;
 956                        msm_write(port, val, UART_CR);
 957                        /*
 958                         * Flush DMA input fifo to memory, this will also
 959                         * trigger DMA RX completion
 960                         */
 961                        dmaengine_terminate_all(dma->chan);
 962                } else if (msm_port->is_uartdm) {
 963                        msm_handle_rx_dm(port, misr);
 964                } else {
 965                        msm_handle_rx(port);
 966                }
 967        }
 968        if (misr & UART_IMR_TXLEV)
 969                msm_handle_tx(port);
 970        if (misr & UART_IMR_DELTA_CTS)
 971                msm_handle_delta_cts(port);
 972
 973        msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
 974        spin_unlock_irqrestore(&port->lock, flags);
 975
 976        return IRQ_HANDLED;
 977}
 978
 979static unsigned int msm_tx_empty(struct uart_port *port)
 980{
 981        return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
 982}
 983
 984static unsigned int msm_get_mctrl(struct uart_port *port)
 985{
 986        return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 987}
 988
 989static void msm_reset(struct uart_port *port)
 990{
 991        struct msm_port *msm_port = UART_TO_MSM(port);
 992        unsigned int mr;
 993
 994        /* reset everything */
 995        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
 996        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 997        msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 998        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
 999        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
1000        msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1001        mr = msm_read(port, UART_MR1);
1002        mr &= ~UART_MR1_RX_RDY_CTL;
1003        msm_write(port, mr, UART_MR1);
1004
1005        /* Disable DM modes */
1006        if (msm_port->is_uartdm)
1007                msm_write(port, 0, UARTDM_DMEN);
1008}
1009
1010static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
1011{
1012        unsigned int mr;
1013
1014        mr = msm_read(port, UART_MR1);
1015
1016        if (!(mctrl & TIOCM_RTS)) {
1017                mr &= ~UART_MR1_RX_RDY_CTL;
1018                msm_write(port, mr, UART_MR1);
1019                msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1020        } else {
1021                mr |= UART_MR1_RX_RDY_CTL;
1022                msm_write(port, mr, UART_MR1);
1023        }
1024}
1025
1026static void msm_break_ctl(struct uart_port *port, int break_ctl)
1027{
1028        if (break_ctl)
1029                msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1030        else
1031                msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1032}
1033
1034struct msm_baud_map {
1035        u16     divisor;
1036        u8      code;
1037        u8      rxstale;
1038};
1039
1040static const struct msm_baud_map *
1041msm_find_best_baud(struct uart_port *port, unsigned int baud,
1042                   unsigned long *rate)
1043{
1044        struct msm_port *msm_port = UART_TO_MSM(port);
1045        unsigned int divisor, result;
1046        unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1047        const struct msm_baud_map *entry, *end, *best;
1048        static const struct msm_baud_map table[] = {
1049                {    1, 0xff, 31 },
1050                {    2, 0xee, 16 },
1051                {    3, 0xdd,  8 },
1052                {    4, 0xcc,  6 },
1053                {    6, 0xbb,  6 },
1054                {    8, 0xaa,  6 },
1055                {   12, 0x99,  6 },
1056                {   16, 0x88,  1 },
1057                {   24, 0x77,  1 },
1058                {   32, 0x66,  1 },
1059                {   48, 0x55,  1 },
1060                {   96, 0x44,  1 },
1061                {  192, 0x33,  1 },
1062                {  384, 0x22,  1 },
1063                {  768, 0x11,  1 },
1064                { 1536, 0x00,  1 },
1065        };
1066
1067        best = table; /* Default to smallest divider */
1068        target = clk_round_rate(msm_port->clk, 16 * baud);
1069        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1070
1071        end = table + ARRAY_SIZE(table);
1072        entry = table;
1073        while (entry < end) {
1074                if (entry->divisor <= divisor) {
1075                        result = target / entry->divisor / 16;
1076                        diff = abs(result - baud);
1077
1078                        /* Keep track of best entry */
1079                        if (diff < best_diff) {
1080                                best_diff = diff;
1081                                best = entry;
1082                                best_rate = target;
1083                        }
1084
1085                        if (result == baud)
1086                                break;
1087                } else if (entry->divisor > divisor) {
1088                        old = target;
1089                        target = clk_round_rate(msm_port->clk, old + 1);
1090                        /*
1091                         * The rate didn't get any faster so we can't do
1092                         * better at dividing it down
1093                         */
1094                        if (target == old)
1095                                break;
1096
1097                        /* Start the divisor search over at this new rate */
1098                        entry = table;
1099                        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1100                        continue;
1101                }
1102                entry++;
1103        }
1104
1105        *rate = best_rate;
1106        return best;
1107}
1108
1109static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1110                             unsigned long *saved_flags)
1111{
1112        unsigned int rxstale, watermark, mask;
1113        struct msm_port *msm_port = UART_TO_MSM(port);
1114        const struct msm_baud_map *entry;
1115        unsigned long flags, rate;
1116
1117        flags = *saved_flags;
1118        spin_unlock_irqrestore(&port->lock, flags);
1119
1120        entry = msm_find_best_baud(port, baud, &rate);
1121        clk_set_rate(msm_port->clk, rate);
1122        baud = rate / 16 / entry->divisor;
1123
1124        spin_lock_irqsave(&port->lock, flags);
1125        *saved_flags = flags;
1126        port->uartclk = rate;
1127
1128        msm_write(port, entry->code, UART_CSR);
1129
1130        /* RX stale watermark */
1131        rxstale = entry->rxstale;
1132        watermark = UART_IPR_STALE_LSB & rxstale;
1133        if (msm_port->is_uartdm) {
1134                mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1135        } else {
1136                watermark |= UART_IPR_RXSTALE_LAST;
1137                mask = UART_IPR_STALE_TIMEOUT_MSB;
1138        }
1139
1140        watermark |= mask & (rxstale << 2);
1141
1142        msm_write(port, watermark, UART_IPR);
1143
1144        /* set RX watermark */
1145        watermark = (port->fifosize * 3) / 4;
1146        msm_write(port, watermark, UART_RFWR);
1147
1148        /* set TX watermark */
1149        msm_write(port, 10, UART_TFWR);
1150
1151        msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1152        msm_reset(port);
1153
1154        /* Enable RX and TX */
1155        msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1156
1157        /* turn on RX and CTS interrupts */
1158        msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1159                        UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1160
1161        msm_write(port, msm_port->imr, UART_IMR);
1162
1163        if (msm_port->is_uartdm) {
1164                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1165                msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1166                msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1167        }
1168
1169        return baud;
1170}
1171
1172static void msm_init_clock(struct uart_port *port)
1173{
1174        struct msm_port *msm_port = UART_TO_MSM(port);
1175
1176        clk_prepare_enable(msm_port->clk);
1177        clk_prepare_enable(msm_port->pclk);
1178        msm_serial_set_mnd_regs(port);
1179}
1180
1181static int msm_startup(struct uart_port *port)
1182{
1183        struct msm_port *msm_port = UART_TO_MSM(port);
1184        unsigned int data, rfr_level, mask;
1185        int ret;
1186
1187        snprintf(msm_port->name, sizeof(msm_port->name),
1188                 "msm_serial%d", port->line);
1189
1190        msm_init_clock(port);
1191
1192        if (likely(port->fifosize > 12))
1193                rfr_level = port->fifosize - 12;
1194        else
1195                rfr_level = port->fifosize;
1196
1197        /* set automatic RFR level */
1198        data = msm_read(port, UART_MR1);
1199
1200        if (msm_port->is_uartdm)
1201                mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1202        else
1203                mask = UART_MR1_AUTO_RFR_LEVEL1;
1204
1205        data &= ~mask;
1206        data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1207        data |= mask & (rfr_level << 2);
1208        data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1209        msm_write(port, data, UART_MR1);
1210
1211        if (msm_port->is_uartdm) {
1212                msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1213                msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1214        }
1215
1216        ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1217                          msm_port->name, port);
1218        if (unlikely(ret))
1219                goto err_irq;
1220
1221        return 0;
1222
1223err_irq:
1224        if (msm_port->is_uartdm)
1225                msm_release_dma(msm_port);
1226
1227        clk_disable_unprepare(msm_port->pclk);
1228        clk_disable_unprepare(msm_port->clk);
1229
1230        return ret;
1231}
1232
1233static void msm_shutdown(struct uart_port *port)
1234{
1235        struct msm_port *msm_port = UART_TO_MSM(port);
1236
1237        msm_port->imr = 0;
1238        msm_write(port, 0, UART_IMR); /* disable interrupts */
1239
1240        if (msm_port->is_uartdm)
1241                msm_release_dma(msm_port);
1242
1243        clk_disable_unprepare(msm_port->clk);
1244
1245        free_irq(port->irq, port);
1246}
1247
1248static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1249                            struct ktermios *old)
1250{
1251        struct msm_port *msm_port = UART_TO_MSM(port);
1252        struct msm_dma *dma = &msm_port->rx_dma;
1253        unsigned long flags;
1254        unsigned int baud, mr;
1255
1256        spin_lock_irqsave(&port->lock, flags);
1257
1258        if (dma->chan) /* Terminate if any */
1259                msm_stop_dma(port, dma);
1260
1261        /* calculate and set baud rate */
1262        baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1263        baud = msm_set_baud_rate(port, baud, &flags);
1264        if (tty_termios_baud_rate(termios))
1265                tty_termios_encode_baud_rate(termios, baud, baud);
1266
1267        /* calculate parity */
1268        mr = msm_read(port, UART_MR2);
1269        mr &= ~UART_MR2_PARITY_MODE;
1270        if (termios->c_cflag & PARENB) {
1271                if (termios->c_cflag & PARODD)
1272                        mr |= UART_MR2_PARITY_MODE_ODD;
1273                else if (termios->c_cflag & CMSPAR)
1274                        mr |= UART_MR2_PARITY_MODE_SPACE;
1275                else
1276                        mr |= UART_MR2_PARITY_MODE_EVEN;
1277        }
1278
1279        /* calculate bits per char */
1280        mr &= ~UART_MR2_BITS_PER_CHAR;
1281        switch (termios->c_cflag & CSIZE) {
1282        case CS5:
1283                mr |= UART_MR2_BITS_PER_CHAR_5;
1284                break;
1285        case CS6:
1286                mr |= UART_MR2_BITS_PER_CHAR_6;
1287                break;
1288        case CS7:
1289                mr |= UART_MR2_BITS_PER_CHAR_7;
1290                break;
1291        case CS8:
1292        default:
1293                mr |= UART_MR2_BITS_PER_CHAR_8;
1294                break;
1295        }
1296
1297        /* calculate stop bits */
1298        mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1299        if (termios->c_cflag & CSTOPB)
1300                mr |= UART_MR2_STOP_BIT_LEN_TWO;
1301        else
1302                mr |= UART_MR2_STOP_BIT_LEN_ONE;
1303
1304        /* set parity, bits per char, and stop bit */
1305        msm_write(port, mr, UART_MR2);
1306
1307        /* calculate and set hardware flow control */
1308        mr = msm_read(port, UART_MR1);
1309        mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1310        if (termios->c_cflag & CRTSCTS) {
1311                mr |= UART_MR1_CTS_CTL;
1312                mr |= UART_MR1_RX_RDY_CTL;
1313        }
1314        msm_write(port, mr, UART_MR1);
1315
1316        /* Configure status bits to ignore based on termio flags. */
1317        port->read_status_mask = 0;
1318        if (termios->c_iflag & INPCK)
1319                port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1320        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1321                port->read_status_mask |= UART_SR_RX_BREAK;
1322
1323        uart_update_timeout(port, termios->c_cflag, baud);
1324
1325        /* Try to use DMA */
1326        msm_start_rx_dma(msm_port);
1327
1328        spin_unlock_irqrestore(&port->lock, flags);
1329}
1330
1331static const char *msm_type(struct uart_port *port)
1332{
1333        return "MSM";
1334}
1335
1336static void msm_release_port(struct uart_port *port)
1337{
1338        struct platform_device *pdev = to_platform_device(port->dev);
1339        struct resource *uart_resource;
1340        resource_size_t size;
1341
1342        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1343        if (unlikely(!uart_resource))
1344                return;
1345        size = resource_size(uart_resource);
1346
1347        release_mem_region(port->mapbase, size);
1348        iounmap(port->membase);
1349        port->membase = NULL;
1350}
1351
1352static int msm_request_port(struct uart_port *port)
1353{
1354        struct platform_device *pdev = to_platform_device(port->dev);
1355        struct resource *uart_resource;
1356        resource_size_t size;
1357        int ret;
1358
1359        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1360        if (unlikely(!uart_resource))
1361                return -ENXIO;
1362
1363        size = resource_size(uart_resource);
1364
1365        if (!request_mem_region(port->mapbase, size, "msm_serial"))
1366                return -EBUSY;
1367
1368        port->membase = ioremap(port->mapbase, size);
1369        if (!port->membase) {
1370                ret = -EBUSY;
1371                goto fail_release_port;
1372        }
1373
1374        return 0;
1375
1376fail_release_port:
1377        release_mem_region(port->mapbase, size);
1378        return ret;
1379}
1380
1381static void msm_config_port(struct uart_port *port, int flags)
1382{
1383        int ret;
1384
1385        if (flags & UART_CONFIG_TYPE) {
1386                port->type = PORT_MSM;
1387                ret = msm_request_port(port);
1388                if (ret)
1389                        return;
1390        }
1391}
1392
1393static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1394{
1395        if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1396                return -EINVAL;
1397        if (unlikely(port->irq != ser->irq))
1398                return -EINVAL;
1399        return 0;
1400}
1401
1402static void msm_power(struct uart_port *port, unsigned int state,
1403                      unsigned int oldstate)
1404{
1405        struct msm_port *msm_port = UART_TO_MSM(port);
1406
1407        switch (state) {
1408        case 0:
1409                clk_prepare_enable(msm_port->clk);
1410                clk_prepare_enable(msm_port->pclk);
1411                break;
1412        case 3:
1413                clk_disable_unprepare(msm_port->clk);
1414                clk_disable_unprepare(msm_port->pclk);
1415                break;
1416        default:
1417                pr_err("msm_serial: Unknown PM state %d\n", state);
1418        }
1419}
1420
1421#ifdef CONFIG_CONSOLE_POLL
1422static int msm_poll_get_char_single(struct uart_port *port)
1423{
1424        struct msm_port *msm_port = UART_TO_MSM(port);
1425        unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1426
1427        if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1428                return NO_POLL_CHAR;
1429
1430        return msm_read(port, rf_reg) & 0xff;
1431}
1432
1433static int msm_poll_get_char_dm(struct uart_port *port)
1434{
1435        int c;
1436        static u32 slop;
1437        static int count;
1438        unsigned char *sp = (unsigned char *)&slop;
1439
1440        /* Check if a previous read had more than one char */
1441        if (count) {
1442                c = sp[sizeof(slop) - count];
1443                count--;
1444        /* Or if FIFO is empty */
1445        } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1446                /*
1447                 * If RX packing buffer has less than a word, force stale to
1448                 * push contents into RX FIFO
1449                 */
1450                count = msm_read(port, UARTDM_RXFS);
1451                count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1452                if (count) {
1453                        msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1454                        slop = msm_read(port, UARTDM_RF);
1455                        c = sp[0];
1456                        count--;
1457                        msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1458                        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1459                        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1460                                  UART_CR);
1461                } else {
1462                        c = NO_POLL_CHAR;
1463                }
1464        /* FIFO has a word */
1465        } else {
1466                slop = msm_read(port, UARTDM_RF);
1467                c = sp[0];
1468                count = sizeof(slop) - 1;
1469        }
1470
1471        return c;
1472}
1473
1474static int msm_poll_get_char(struct uart_port *port)
1475{
1476        u32 imr;
1477        int c;
1478        struct msm_port *msm_port = UART_TO_MSM(port);
1479
1480        /* Disable all interrupts */
1481        imr = msm_read(port, UART_IMR);
1482        msm_write(port, 0, UART_IMR);
1483
1484        if (msm_port->is_uartdm)
1485                c = msm_poll_get_char_dm(port);
1486        else
1487                c = msm_poll_get_char_single(port);
1488
1489        /* Enable interrupts */
1490        msm_write(port, imr, UART_IMR);
1491
1492        return c;
1493}
1494
1495static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1496{
1497        u32 imr;
1498        struct msm_port *msm_port = UART_TO_MSM(port);
1499
1500        /* Disable all interrupts */
1501        imr = msm_read(port, UART_IMR);
1502        msm_write(port, 0, UART_IMR);
1503
1504        if (msm_port->is_uartdm)
1505                msm_reset_dm_count(port, 1);
1506
1507        /* Wait until FIFO is empty */
1508        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1509                cpu_relax();
1510
1511        /* Write a character */
1512        msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1513
1514        /* Wait until FIFO is empty */
1515        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1516                cpu_relax();
1517
1518        /* Enable interrupts */
1519        msm_write(port, imr, UART_IMR);
1520}
1521#endif
1522
1523static const struct uart_ops msm_uart_pops = {
1524        .tx_empty = msm_tx_empty,
1525        .set_mctrl = msm_set_mctrl,
1526        .get_mctrl = msm_get_mctrl,
1527        .stop_tx = msm_stop_tx,
1528        .start_tx = msm_start_tx,
1529        .stop_rx = msm_stop_rx,
1530        .enable_ms = msm_enable_ms,
1531        .break_ctl = msm_break_ctl,
1532        .startup = msm_startup,
1533        .shutdown = msm_shutdown,
1534        .set_termios = msm_set_termios,
1535        .type = msm_type,
1536        .release_port = msm_release_port,
1537        .request_port = msm_request_port,
1538        .config_port = msm_config_port,
1539        .verify_port = msm_verify_port,
1540        .pm = msm_power,
1541#ifdef CONFIG_CONSOLE_POLL
1542        .poll_get_char  = msm_poll_get_char,
1543        .poll_put_char  = msm_poll_put_char,
1544#endif
1545};
1546
1547static struct msm_port msm_uart_ports[] = {
1548        {
1549                .uart = {
1550                        .iotype = UPIO_MEM,
1551                        .ops = &msm_uart_pops,
1552                        .flags = UPF_BOOT_AUTOCONF,
1553                        .fifosize = 64,
1554                        .line = 0,
1555                },
1556        },
1557        {
1558                .uart = {
1559                        .iotype = UPIO_MEM,
1560                        .ops = &msm_uart_pops,
1561                        .flags = UPF_BOOT_AUTOCONF,
1562                        .fifosize = 64,
1563                        .line = 1,
1564                },
1565        },
1566        {
1567                .uart = {
1568                        .iotype = UPIO_MEM,
1569                        .ops = &msm_uart_pops,
1570                        .flags = UPF_BOOT_AUTOCONF,
1571                        .fifosize = 64,
1572                        .line = 2,
1573                },
1574        },
1575};
1576
1577#define UART_NR ARRAY_SIZE(msm_uart_ports)
1578
1579static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1580{
1581        return &msm_uart_ports[line].uart;
1582}
1583
1584#ifdef CONFIG_SERIAL_MSM_CONSOLE
1585static void __msm_console_write(struct uart_port *port, const char *s,
1586                                unsigned int count, bool is_uartdm)
1587{
1588        int i;
1589        int num_newlines = 0;
1590        bool replaced = false;
1591        void __iomem *tf;
1592        int locked = 1;
1593
1594        if (is_uartdm)
1595                tf = port->membase + UARTDM_TF;
1596        else
1597                tf = port->membase + UART_TF;
1598
1599        /* Account for newlines that will get a carriage return added */
1600        for (i = 0; i < count; i++)
1601                if (s[i] == '\n')
1602                        num_newlines++;
1603        count += num_newlines;
1604
1605        if (port->sysrq)
1606                locked = 0;
1607        else if (oops_in_progress)
1608                locked = spin_trylock(&port->lock);
1609        else
1610                spin_lock(&port->lock);
1611
1612        if (is_uartdm)
1613                msm_reset_dm_count(port, count);
1614
1615        i = 0;
1616        while (i < count) {
1617                int j;
1618                unsigned int num_chars;
1619                char buf[4] = { 0 };
1620
1621                if (is_uartdm)
1622                        num_chars = min(count - i, (unsigned int)sizeof(buf));
1623                else
1624                        num_chars = 1;
1625
1626                for (j = 0; j < num_chars; j++) {
1627                        char c = *s;
1628
1629                        if (c == '\n' && !replaced) {
1630                                buf[j] = '\r';
1631                                j++;
1632                                replaced = true;
1633                        }
1634                        if (j < num_chars) {
1635                                buf[j] = c;
1636                                s++;
1637                                replaced = false;
1638                        }
1639                }
1640
1641                while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1642                        cpu_relax();
1643
1644                iowrite32_rep(tf, buf, 1);
1645                i += num_chars;
1646        }
1647
1648        if (locked)
1649                spin_unlock(&port->lock);
1650}
1651
1652static void msm_console_write(struct console *co, const char *s,
1653                              unsigned int count)
1654{
1655        struct uart_port *port;
1656        struct msm_port *msm_port;
1657
1658        BUG_ON(co->index < 0 || co->index >= UART_NR);
1659
1660        port = msm_get_port_from_line(co->index);
1661        msm_port = UART_TO_MSM(port);
1662
1663        __msm_console_write(port, s, count, msm_port->is_uartdm);
1664}
1665
1666static int msm_console_setup(struct console *co, char *options)
1667{
1668        struct uart_port *port;
1669        int baud = 115200;
1670        int bits = 8;
1671        int parity = 'n';
1672        int flow = 'n';
1673
1674        if (unlikely(co->index >= UART_NR || co->index < 0))
1675                return -ENXIO;
1676
1677        port = msm_get_port_from_line(co->index);
1678
1679        if (unlikely(!port->membase))
1680                return -ENXIO;
1681
1682        msm_init_clock(port);
1683
1684        if (options)
1685                uart_parse_options(options, &baud, &parity, &bits, &flow);
1686
1687        pr_info("msm_serial: console setup on port #%d\n", port->line);
1688
1689        return uart_set_options(port, co, baud, parity, bits, flow);
1690}
1691
1692static void
1693msm_serial_early_write(struct console *con, const char *s, unsigned n)
1694{
1695        struct earlycon_device *dev = con->data;
1696
1697        __msm_console_write(&dev->port, s, n, false);
1698}
1699
1700static int __init
1701msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1702{
1703        if (!device->port.membase)
1704                return -ENODEV;
1705
1706        device->con->write = msm_serial_early_write;
1707        return 0;
1708}
1709OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1710                    msm_serial_early_console_setup);
1711
1712static void
1713msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1714{
1715        struct earlycon_device *dev = con->data;
1716
1717        __msm_console_write(&dev->port, s, n, true);
1718}
1719
1720static int __init
1721msm_serial_early_console_setup_dm(struct earlycon_device *device,
1722                                  const char *opt)
1723{
1724        if (!device->port.membase)
1725                return -ENODEV;
1726
1727        device->con->write = msm_serial_early_write_dm;
1728        return 0;
1729}
1730OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1731                    msm_serial_early_console_setup_dm);
1732
1733static struct uart_driver msm_uart_driver;
1734
1735static struct console msm_console = {
1736        .name = "ttyMSM",
1737        .write = msm_console_write,
1738        .device = uart_console_device,
1739        .setup = msm_console_setup,
1740        .flags = CON_PRINTBUFFER,
1741        .index = -1,
1742        .data = &msm_uart_driver,
1743};
1744
1745#define MSM_CONSOLE     (&msm_console)
1746
1747#else
1748#define MSM_CONSOLE     NULL
1749#endif
1750
1751static struct uart_driver msm_uart_driver = {
1752        .owner = THIS_MODULE,
1753        .driver_name = "msm_serial",
1754        .dev_name = "ttyMSM",
1755        .nr = UART_NR,
1756        .cons = MSM_CONSOLE,
1757};
1758
1759static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1760
1761static const struct of_device_id msm_uartdm_table[] = {
1762        { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1763        { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1764        { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1765        { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1766        { }
1767};
1768
1769static int msm_serial_probe(struct platform_device *pdev)
1770{
1771        struct msm_port *msm_port;
1772        struct resource *resource;
1773        struct uart_port *port;
1774        const struct of_device_id *id;
1775        int irq, line;
1776
1777        if (pdev->dev.of_node)
1778                line = of_alias_get_id(pdev->dev.of_node, "serial");
1779        else
1780                line = pdev->id;
1781
1782        if (line < 0)
1783                line = atomic_inc_return(&msm_uart_next_id) - 1;
1784
1785        if (unlikely(line < 0 || line >= UART_NR))
1786                return -ENXIO;
1787
1788        dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1789
1790        port = msm_get_port_from_line(line);
1791        port->dev = &pdev->dev;
1792        msm_port = UART_TO_MSM(port);
1793
1794        id = of_match_device(msm_uartdm_table, &pdev->dev);
1795        if (id)
1796                msm_port->is_uartdm = (unsigned long)id->data;
1797        else
1798                msm_port->is_uartdm = 0;
1799
1800        msm_port->clk = devm_clk_get(&pdev->dev, "core");
1801        if (IS_ERR(msm_port->clk))
1802                return PTR_ERR(msm_port->clk);
1803
1804        if (msm_port->is_uartdm) {
1805                msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1806                if (IS_ERR(msm_port->pclk))
1807                        return PTR_ERR(msm_port->pclk);
1808        }
1809
1810        port->uartclk = clk_get_rate(msm_port->clk);
1811        dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1812
1813        resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1814        if (unlikely(!resource))
1815                return -ENXIO;
1816        port->mapbase = resource->start;
1817
1818        irq = platform_get_irq(pdev, 0);
1819        if (unlikely(irq < 0))
1820                return -ENXIO;
1821        port->irq = irq;
1822        port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MSM_CONSOLE);
1823
1824        platform_set_drvdata(pdev, port);
1825
1826        return uart_add_one_port(&msm_uart_driver, port);
1827}
1828
1829static int msm_serial_remove(struct platform_device *pdev)
1830{
1831        struct uart_port *port = platform_get_drvdata(pdev);
1832
1833        uart_remove_one_port(&msm_uart_driver, port);
1834
1835        return 0;
1836}
1837
1838static const struct of_device_id msm_match_table[] = {
1839        { .compatible = "qcom,msm-uart" },
1840        { .compatible = "qcom,msm-uartdm" },
1841        {}
1842};
1843MODULE_DEVICE_TABLE(of, msm_match_table);
1844
1845static int __maybe_unused msm_serial_suspend(struct device *dev)
1846{
1847        struct msm_port *port = dev_get_drvdata(dev);
1848
1849        uart_suspend_port(&msm_uart_driver, &port->uart);
1850
1851        return 0;
1852}
1853
1854static int __maybe_unused msm_serial_resume(struct device *dev)
1855{
1856        struct msm_port *port = dev_get_drvdata(dev);
1857
1858        uart_resume_port(&msm_uart_driver, &port->uart);
1859
1860        return 0;
1861}
1862
1863static const struct dev_pm_ops msm_serial_dev_pm_ops = {
1864        SET_SYSTEM_SLEEP_PM_OPS(msm_serial_suspend, msm_serial_resume)
1865};
1866
1867static struct platform_driver msm_platform_driver = {
1868        .remove = msm_serial_remove,
1869        .probe = msm_serial_probe,
1870        .driver = {
1871                .name = "msm_serial",
1872                .pm = &msm_serial_dev_pm_ops,
1873                .of_match_table = msm_match_table,
1874        },
1875};
1876
1877static int __init msm_serial_init(void)
1878{
1879        int ret;
1880
1881        ret = uart_register_driver(&msm_uart_driver);
1882        if (unlikely(ret))
1883                return ret;
1884
1885        ret = platform_driver_register(&msm_platform_driver);
1886        if (unlikely(ret))
1887                uart_unregister_driver(&msm_uart_driver);
1888
1889        pr_info("msm_serial: driver initialized\n");
1890
1891        return ret;
1892}
1893
1894static void __exit msm_serial_exit(void)
1895{
1896        platform_driver_unregister(&msm_platform_driver);
1897        uart_unregister_driver(&msm_uart_driver);
1898}
1899
1900module_init(msm_serial_init);
1901module_exit(msm_serial_exit);
1902
1903MODULE_AUTHOR("Robert Love <rlove@google.com>");
1904MODULE_DESCRIPTION("Driver for msm7x serial device");
1905MODULE_LICENSE("GPL");
1906