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#if defined(CONFIG_SERIAL_MSM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  11# define SUPPORT_SYSRQ
  12#endif
  13
  14#include <linux/kernel.h>
  15#include <linux/atomic.h>
  16#include <linux/dma-mapping.h>
  17#include <linux/dmaengine.h>
  18#include <linux/module.h>
  19#include <linux/io.h>
  20#include <linux/ioport.h>
  21#include <linux/interrupt.h>
  22#include <linux/init.h>
  23#include <linux/console.h>
  24#include <linux/tty.h>
  25#include <linux/tty_flip.h>
  26#include <linux/serial_core.h>
  27#include <linux/slab.h>
  28#include <linux/clk.h>
  29#include <linux/platform_device.h>
  30#include <linux/delay.h>
  31#include <linux/of.h>
  32#include <linux/of_device.h>
  33#include <linux/wait.h>
  34
  35#define UART_MR1                        0x0000
  36
  37#define UART_MR1_AUTO_RFR_LEVEL0        0x3F
  38#define UART_MR1_AUTO_RFR_LEVEL1        0x3FF00
  39#define UART_DM_MR1_AUTO_RFR_LEVEL1     0xFFFFFF00
  40#define UART_MR1_RX_RDY_CTL             BIT(7)
  41#define UART_MR1_CTS_CTL                BIT(6)
  42
  43#define UART_MR2                        0x0004
  44#define UART_MR2_ERROR_MODE             BIT(6)
  45#define UART_MR2_BITS_PER_CHAR          0x30
  46#define UART_MR2_BITS_PER_CHAR_5        (0x0 << 4)
  47#define UART_MR2_BITS_PER_CHAR_6        (0x1 << 4)
  48#define UART_MR2_BITS_PER_CHAR_7        (0x2 << 4)
  49#define UART_MR2_BITS_PER_CHAR_8        (0x3 << 4)
  50#define UART_MR2_STOP_BIT_LEN_ONE       (0x1 << 2)
  51#define UART_MR2_STOP_BIT_LEN_TWO       (0x3 << 2)
  52#define UART_MR2_PARITY_MODE_NONE       0x0
  53#define UART_MR2_PARITY_MODE_ODD        0x1
  54#define UART_MR2_PARITY_MODE_EVEN       0x2
  55#define UART_MR2_PARITY_MODE_SPACE      0x3
  56#define UART_MR2_PARITY_MODE            0x3
  57
  58#define UART_CSR                        0x0008
  59
  60#define UART_TF                         0x000C
  61#define UARTDM_TF                       0x0070
  62
  63#define UART_CR                         0x0010
  64#define UART_CR_CMD_NULL                (0 << 4)
  65#define UART_CR_CMD_RESET_RX            (1 << 4)
  66#define UART_CR_CMD_RESET_TX            (2 << 4)
  67#define UART_CR_CMD_RESET_ERR           (3 << 4)
  68#define UART_CR_CMD_RESET_BREAK_INT     (4 << 4)
  69#define UART_CR_CMD_START_BREAK         (5 << 4)
  70#define UART_CR_CMD_STOP_BREAK          (6 << 4)
  71#define UART_CR_CMD_RESET_CTS           (7 << 4)
  72#define UART_CR_CMD_RESET_STALE_INT     (8 << 4)
  73#define UART_CR_CMD_PACKET_MODE         (9 << 4)
  74#define UART_CR_CMD_MODE_RESET          (12 << 4)
  75#define UART_CR_CMD_SET_RFR             (13 << 4)
  76#define UART_CR_CMD_RESET_RFR           (14 << 4)
  77#define UART_CR_CMD_PROTECTION_EN       (16 << 4)
  78#define UART_CR_CMD_STALE_EVENT_DISABLE (6 << 8)
  79#define UART_CR_CMD_STALE_EVENT_ENABLE  (80 << 4)
  80#define UART_CR_CMD_FORCE_STALE         (4 << 8)
  81#define UART_CR_CMD_RESET_TX_READY      (3 << 8)
  82#define UART_CR_TX_DISABLE              BIT(3)
  83#define UART_CR_TX_ENABLE               BIT(2)
  84#define UART_CR_RX_DISABLE              BIT(1)
  85#define UART_CR_RX_ENABLE               BIT(0)
  86#define UART_CR_CMD_RESET_RXBREAK_START ((1 << 11) | (2 << 4))
  87
  88#define UART_IMR                        0x0014
  89#define UART_IMR_TXLEV                  BIT(0)
  90#define UART_IMR_RXSTALE                BIT(3)
  91#define UART_IMR_RXLEV                  BIT(4)
  92#define UART_IMR_DELTA_CTS              BIT(5)
  93#define UART_IMR_CURRENT_CTS            BIT(6)
  94#define UART_IMR_RXBREAK_START          BIT(10)
  95
  96#define UART_IPR_RXSTALE_LAST           0x20
  97#define UART_IPR_STALE_LSB              0x1F
  98#define UART_IPR_STALE_TIMEOUT_MSB      0x3FF80
  99#define UART_DM_IPR_STALE_TIMEOUT_MSB   0xFFFFFF80
 100
 101#define UART_IPR                        0x0018
 102#define UART_TFWR                       0x001C
 103#define UART_RFWR                       0x0020
 104#define UART_HCR                        0x0024
 105
 106#define UART_MREG                       0x0028
 107#define UART_NREG                       0x002C
 108#define UART_DREG                       0x0030
 109#define UART_MNDREG                     0x0034
 110#define UART_IRDA                       0x0038
 111#define UART_MISR_MODE                  0x0040
 112#define UART_MISR_RESET                 0x0044
 113#define UART_MISR_EXPORT                0x0048
 114#define UART_MISR_VAL                   0x004C
 115#define UART_TEST_CTRL                  0x0050
 116
 117#define UART_SR                         0x0008
 118#define UART_SR_HUNT_CHAR               BIT(7)
 119#define UART_SR_RX_BREAK                BIT(6)
 120#define UART_SR_PAR_FRAME_ERR           BIT(5)
 121#define UART_SR_OVERRUN                 BIT(4)
 122#define UART_SR_TX_EMPTY                BIT(3)
 123#define UART_SR_TX_READY                BIT(2)
 124#define UART_SR_RX_FULL                 BIT(1)
 125#define UART_SR_RX_READY                BIT(0)
 126
 127#define UART_RF                         0x000C
 128#define UARTDM_RF                       0x0070
 129#define UART_MISR                       0x0010
 130#define UART_ISR                        0x0014
 131#define UART_ISR_TX_READY               BIT(7)
 132
 133#define UARTDM_RXFS                     0x50
 134#define UARTDM_RXFS_BUF_SHIFT           0x7
 135#define UARTDM_RXFS_BUF_MASK            0x7
 136
 137#define UARTDM_DMEN                     0x3C
 138#define UARTDM_DMEN_RX_SC_ENABLE        BIT(5)
 139#define UARTDM_DMEN_TX_SC_ENABLE        BIT(4)
 140
 141#define UARTDM_DMEN_TX_BAM_ENABLE       BIT(2)  /* UARTDM_1P4 */
 142#define UARTDM_DMEN_TX_DM_ENABLE        BIT(0)  /* < UARTDM_1P4 */
 143
 144#define UARTDM_DMEN_RX_BAM_ENABLE       BIT(3)  /* UARTDM_1P4 */
 145#define UARTDM_DMEN_RX_DM_ENABLE        BIT(1)  /* < UARTDM_1P4 */
 146
 147#define UARTDM_DMRX                     0x34
 148#define UARTDM_NCF_TX                   0x40
 149#define UARTDM_RX_TOTAL_SNAP            0x38
 150
 151#define UARTDM_BURST_SIZE               16   /* in bytes */
 152#define UARTDM_TX_AIGN(x)               ((x) & ~0x3) /* valid for > 1p3 */
 153#define UARTDM_TX_MAX                   256   /* in bytes, valid for <= 1p3 */
 154#define UARTDM_RX_SIZE                  (UART_XMIT_SIZE / 4)
 155
 156enum {
 157        UARTDM_1P1 = 1,
 158        UARTDM_1P2,
 159        UARTDM_1P3,
 160        UARTDM_1P4,
 161};
 162
 163struct msm_dma {
 164        struct dma_chan         *chan;
 165        enum dma_data_direction dir;
 166        dma_addr_t              phys;
 167        unsigned char           *virt;
 168        dma_cookie_t            cookie;
 169        u32                     enable_bit;
 170        unsigned int            count;
 171        struct dma_async_tx_descriptor  *desc;
 172};
 173
 174struct msm_port {
 175        struct uart_port        uart;
 176        char                    name[16];
 177        struct clk              *clk;
 178        struct clk              *pclk;
 179        unsigned int            imr;
 180        int                     is_uartdm;
 181        unsigned int            old_snap_state;
 182        bool                    break_detected;
 183        struct msm_dma          tx_dma;
 184        struct msm_dma          rx_dma;
 185};
 186
 187#define UART_TO_MSM(uart_port)  container_of(uart_port, struct msm_port, uart)
 188
 189static
 190void msm_write(struct uart_port *port, unsigned int val, unsigned int off)
 191{
 192        writel_relaxed(val, port->membase + off);
 193}
 194
 195static
 196unsigned int msm_read(struct uart_port *port, unsigned int off)
 197{
 198        return readl_relaxed(port->membase + off);
 199}
 200
 201/*
 202 * Setup the MND registers to use the TCXO clock.
 203 */
 204static void msm_serial_set_mnd_regs_tcxo(struct uart_port *port)
 205{
 206        msm_write(port, 0x06, UART_MREG);
 207        msm_write(port, 0xF1, UART_NREG);
 208        msm_write(port, 0x0F, UART_DREG);
 209        msm_write(port, 0x1A, UART_MNDREG);
 210        port->uartclk = 1843200;
 211}
 212
 213/*
 214 * Setup the MND registers to use the TCXO clock divided by 4.
 215 */
 216static void msm_serial_set_mnd_regs_tcxoby4(struct uart_port *port)
 217{
 218        msm_write(port, 0x18, UART_MREG);
 219        msm_write(port, 0xF6, UART_NREG);
 220        msm_write(port, 0x0F, UART_DREG);
 221        msm_write(port, 0x0A, UART_MNDREG);
 222        port->uartclk = 1843200;
 223}
 224
 225static void msm_serial_set_mnd_regs(struct uart_port *port)
 226{
 227        struct msm_port *msm_port = UART_TO_MSM(port);
 228
 229        /*
 230         * These registers don't exist so we change the clk input rate
 231         * on uartdm hardware instead
 232         */
 233        if (msm_port->is_uartdm)
 234                return;
 235
 236        if (port->uartclk == 19200000)
 237                msm_serial_set_mnd_regs_tcxo(port);
 238        else if (port->uartclk == 4800000)
 239                msm_serial_set_mnd_regs_tcxoby4(port);
 240}
 241
 242static void msm_handle_tx(struct uart_port *port);
 243static void msm_start_rx_dma(struct msm_port *msm_port);
 244
 245static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
 246{
 247        struct device *dev = port->dev;
 248        unsigned int mapped;
 249        u32 val;
 250
 251        mapped = dma->count;
 252        dma->count = 0;
 253
 254        dmaengine_terminate_all(dma->chan);
 255
 256        /*
 257         * DMA Stall happens if enqueue and flush command happens concurrently.
 258         * For example before changing the baud rate/protocol configuration and
 259         * sending flush command to ADM, disable the channel of UARTDM.
 260         * Note: should not reset the receiver here immediately as it is not
 261         * suggested to do disable/reset or reset/disable at the same time.
 262         */
 263        val = msm_read(port, UARTDM_DMEN);
 264        val &= ~dma->enable_bit;
 265        msm_write(port, val, UARTDM_DMEN);
 266
 267        if (mapped)
 268                dma_unmap_single(dev, dma->phys, mapped, dma->dir);
 269}
 270
 271static void msm_release_dma(struct msm_port *msm_port)
 272{
 273        struct msm_dma *dma;
 274
 275        dma = &msm_port->tx_dma;
 276        if (dma->chan) {
 277                msm_stop_dma(&msm_port->uart, dma);
 278                dma_release_channel(dma->chan);
 279        }
 280
 281        memset(dma, 0, sizeof(*dma));
 282
 283        dma = &msm_port->rx_dma;
 284        if (dma->chan) {
 285                msm_stop_dma(&msm_port->uart, dma);
 286                dma_release_channel(dma->chan);
 287                kfree(dma->virt);
 288        }
 289
 290        memset(dma, 0, sizeof(*dma));
 291}
 292
 293static void msm_request_tx_dma(struct msm_port *msm_port, resource_size_t base)
 294{
 295        struct device *dev = msm_port->uart.dev;
 296        struct dma_slave_config conf;
 297        struct msm_dma *dma;
 298        u32 crci = 0;
 299        int ret;
 300
 301        dma = &msm_port->tx_dma;
 302
 303        /* allocate DMA resources, if available */
 304        dma->chan = dma_request_slave_channel_reason(dev, "tx");
 305        if (IS_ERR(dma->chan))
 306                goto no_tx;
 307
 308        of_property_read_u32(dev->of_node, "qcom,tx-crci", &crci);
 309
 310        memset(&conf, 0, sizeof(conf));
 311        conf.direction = DMA_MEM_TO_DEV;
 312        conf.device_fc = true;
 313        conf.dst_addr = base + UARTDM_TF;
 314        conf.dst_maxburst = UARTDM_BURST_SIZE;
 315        conf.slave_id = crci;
 316
 317        ret = dmaengine_slave_config(dma->chan, &conf);
 318        if (ret)
 319                goto rel_tx;
 320
 321        dma->dir = DMA_TO_DEVICE;
 322
 323        if (msm_port->is_uartdm < UARTDM_1P4)
 324                dma->enable_bit = UARTDM_DMEN_TX_DM_ENABLE;
 325        else
 326                dma->enable_bit = UARTDM_DMEN_TX_BAM_ENABLE;
 327
 328        return;
 329
 330rel_tx:
 331        dma_release_channel(dma->chan);
 332no_tx:
 333        memset(dma, 0, sizeof(*dma));
 334}
 335
 336static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
 337{
 338        struct device *dev = msm_port->uart.dev;
 339        struct dma_slave_config conf;
 340        struct msm_dma *dma;
 341        u32 crci = 0;
 342        int ret;
 343
 344        dma = &msm_port->rx_dma;
 345
 346        /* allocate DMA resources, if available */
 347        dma->chan = dma_request_slave_channel_reason(dev, "rx");
 348        if (IS_ERR(dma->chan))
 349                goto no_rx;
 350
 351        of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
 352
 353        dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
 354        if (!dma->virt)
 355                goto rel_rx;
 356
 357        memset(&conf, 0, sizeof(conf));
 358        conf.direction = DMA_DEV_TO_MEM;
 359        conf.device_fc = true;
 360        conf.src_addr = base + UARTDM_RF;
 361        conf.src_maxburst = UARTDM_BURST_SIZE;
 362        conf.slave_id = crci;
 363
 364        ret = dmaengine_slave_config(dma->chan, &conf);
 365        if (ret)
 366                goto err;
 367
 368        dma->dir = DMA_FROM_DEVICE;
 369
 370        if (msm_port->is_uartdm < UARTDM_1P4)
 371                dma->enable_bit = UARTDM_DMEN_RX_DM_ENABLE;
 372        else
 373                dma->enable_bit = UARTDM_DMEN_RX_BAM_ENABLE;
 374
 375        return;
 376err:
 377        kfree(dma->virt);
 378rel_rx:
 379        dma_release_channel(dma->chan);
 380no_rx:
 381        memset(dma, 0, sizeof(*dma));
 382}
 383
 384static inline void msm_wait_for_xmitr(struct uart_port *port)
 385{
 386        while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
 387                if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
 388                        break;
 389                udelay(1);
 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                return;
 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}
 661
 662static void msm_stop_rx(struct uart_port *port)
 663{
 664        struct msm_port *msm_port = UART_TO_MSM(port);
 665        struct msm_dma *dma = &msm_port->rx_dma;
 666
 667        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 668        msm_write(port, msm_port->imr, UART_IMR);
 669
 670        if (dma->chan)
 671                msm_stop_dma(port, dma);
 672}
 673
 674static void msm_enable_ms(struct uart_port *port)
 675{
 676        struct msm_port *msm_port = UART_TO_MSM(port);
 677
 678        msm_port->imr |= UART_IMR_DELTA_CTS;
 679        msm_write(port, msm_port->imr, UART_IMR);
 680}
 681
 682static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
 683{
 684        struct tty_port *tport = &port->state->port;
 685        unsigned int sr;
 686        int count = 0;
 687        struct msm_port *msm_port = UART_TO_MSM(port);
 688
 689        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 690                port->icount.overrun++;
 691                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 692                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 693        }
 694
 695        if (misr & UART_IMR_RXSTALE) {
 696                count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
 697                        msm_port->old_snap_state;
 698                msm_port->old_snap_state = 0;
 699        } else {
 700                count = 4 * (msm_read(port, UART_RFWR));
 701                msm_port->old_snap_state += count;
 702        }
 703
 704        /* TODO: Precise error reporting */
 705
 706        port->icount.rx += count;
 707
 708        while (count > 0) {
 709                unsigned char buf[4];
 710                int sysrq, r_count, i;
 711
 712                sr = msm_read(port, UART_SR);
 713                if ((sr & UART_SR_RX_READY) == 0) {
 714                        msm_port->old_snap_state -= count;
 715                        break;
 716                }
 717
 718                ioread32_rep(port->membase + UARTDM_RF, buf, 1);
 719                r_count = min_t(int, count, sizeof(buf));
 720
 721                for (i = 0; i < r_count; i++) {
 722                        char flag = TTY_NORMAL;
 723
 724                        if (msm_port->break_detected && buf[i] == 0) {
 725                                port->icount.brk++;
 726                                flag = TTY_BREAK;
 727                                msm_port->break_detected = false;
 728                                if (uart_handle_break(port))
 729                                        continue;
 730                        }
 731
 732                        if (!(port->read_status_mask & UART_SR_RX_BREAK))
 733                                flag = TTY_NORMAL;
 734
 735                        spin_unlock(&port->lock);
 736                        sysrq = uart_handle_sysrq_char(port, buf[i]);
 737                        spin_lock(&port->lock);
 738                        if (!sysrq)
 739                                tty_insert_flip_char(tport, buf[i], flag);
 740                }
 741                count -= r_count;
 742        }
 743
 744        spin_unlock(&port->lock);
 745        tty_flip_buffer_push(tport);
 746        spin_lock(&port->lock);
 747
 748        if (misr & (UART_IMR_RXSTALE))
 749                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 750        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
 751        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 752
 753        /* Try to use DMA */
 754        msm_start_rx_dma(msm_port);
 755}
 756
 757static void msm_handle_rx(struct uart_port *port)
 758{
 759        struct tty_port *tport = &port->state->port;
 760        unsigned int sr;
 761
 762        /*
 763         * Handle overrun. My understanding of the hardware is that overrun
 764         * is not tied to the RX buffer, so we handle the case out of band.
 765         */
 766        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 767                port->icount.overrun++;
 768                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 769                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 770        }
 771
 772        /* and now the main RX loop */
 773        while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
 774                unsigned int c;
 775                char flag = TTY_NORMAL;
 776                int sysrq;
 777
 778                c = msm_read(port, UART_RF);
 779
 780                if (sr & UART_SR_RX_BREAK) {
 781                        port->icount.brk++;
 782                        if (uart_handle_break(port))
 783                                continue;
 784                } else if (sr & UART_SR_PAR_FRAME_ERR) {
 785                        port->icount.frame++;
 786                } else {
 787                        port->icount.rx++;
 788                }
 789
 790                /* Mask conditions we're ignorning. */
 791                sr &= port->read_status_mask;
 792
 793                if (sr & UART_SR_RX_BREAK)
 794                        flag = TTY_BREAK;
 795                else if (sr & UART_SR_PAR_FRAME_ERR)
 796                        flag = TTY_FRAME;
 797
 798                spin_unlock(&port->lock);
 799                sysrq = uart_handle_sysrq_char(port, c);
 800                spin_lock(&port->lock);
 801                if (!sysrq)
 802                        tty_insert_flip_char(tport, c, flag);
 803        }
 804
 805        spin_unlock(&port->lock);
 806        tty_flip_buffer_push(tport);
 807        spin_lock(&port->lock);
 808}
 809
 810static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
 811{
 812        struct circ_buf *xmit = &port->state->xmit;
 813        struct msm_port *msm_port = UART_TO_MSM(port);
 814        unsigned int num_chars;
 815        unsigned int tf_pointer = 0;
 816        void __iomem *tf;
 817
 818        if (msm_port->is_uartdm)
 819                tf = port->membase + UARTDM_TF;
 820        else
 821                tf = port->membase + UART_TF;
 822
 823        if (tx_count && msm_port->is_uartdm)
 824                msm_reset_dm_count(port, tx_count);
 825
 826        while (tf_pointer < tx_count) {
 827                int i;
 828                char buf[4] = { 0 };
 829
 830                if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
 831                        break;
 832
 833                if (msm_port->is_uartdm)
 834                        num_chars = min(tx_count - tf_pointer,
 835                                        (unsigned int)sizeof(buf));
 836                else
 837                        num_chars = 1;
 838
 839                for (i = 0; i < num_chars; i++) {
 840                        buf[i] = xmit->buf[xmit->tail + i];
 841                        port->icount.tx++;
 842                }
 843
 844                iowrite32_rep(tf, buf, 1);
 845                xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
 846                tf_pointer += num_chars;
 847        }
 848
 849        /* disable tx interrupts if nothing more to send */
 850        if (uart_circ_empty(xmit))
 851                msm_stop_tx(port);
 852
 853        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 854                uart_write_wakeup(port);
 855}
 856
 857static void msm_handle_tx(struct uart_port *port)
 858{
 859        struct msm_port *msm_port = UART_TO_MSM(port);
 860        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 861        struct msm_dma *dma = &msm_port->tx_dma;
 862        unsigned int pio_count, dma_count, dma_min;
 863        void __iomem *tf;
 864        int err = 0;
 865
 866        if (port->x_char) {
 867                if (msm_port->is_uartdm)
 868                        tf = port->membase + UARTDM_TF;
 869                else
 870                        tf = port->membase + UART_TF;
 871
 872                if (msm_port->is_uartdm)
 873                        msm_reset_dm_count(port, 1);
 874
 875                iowrite8_rep(tf, &port->x_char, 1);
 876                port->icount.tx++;
 877                port->x_char = 0;
 878                return;
 879        }
 880
 881        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 882                msm_stop_tx(port);
 883                return;
 884        }
 885
 886        pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 887        dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 888
 889        dma_min = 1;    /* Always DMA */
 890        if (msm_port->is_uartdm > UARTDM_1P3) {
 891                dma_count = UARTDM_TX_AIGN(dma_count);
 892                dma_min = UARTDM_BURST_SIZE;
 893        } else {
 894                if (dma_count > UARTDM_TX_MAX)
 895                        dma_count = UARTDM_TX_MAX;
 896        }
 897
 898        if (pio_count > port->fifosize)
 899                pio_count = port->fifosize;
 900
 901        if (!dma->chan || dma_count < dma_min)
 902                msm_handle_tx_pio(port, pio_count);
 903        else
 904                err = msm_handle_tx_dma(msm_port, dma_count);
 905
 906        if (err)        /* fall back to PIO mode */
 907                msm_handle_tx_pio(port, pio_count);
 908}
 909
 910static void msm_handle_delta_cts(struct uart_port *port)
 911{
 912        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 913        port->icount.cts++;
 914        wake_up_interruptible(&port->state->port.delta_msr_wait);
 915}
 916
 917static irqreturn_t msm_uart_irq(int irq, void *dev_id)
 918{
 919        struct uart_port *port = dev_id;
 920        struct msm_port *msm_port = UART_TO_MSM(port);
 921        struct msm_dma *dma = &msm_port->rx_dma;
 922        unsigned long flags;
 923        unsigned int misr;
 924        u32 val;
 925
 926        spin_lock_irqsave(&port->lock, flags);
 927        misr = msm_read(port, UART_MISR);
 928        msm_write(port, 0, UART_IMR); /* disable interrupt */
 929
 930        if (misr & UART_IMR_RXBREAK_START) {
 931                msm_port->break_detected = true;
 932                msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
 933        }
 934
 935        if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
 936                if (dma->count) {
 937                        val = UART_CR_CMD_STALE_EVENT_DISABLE;
 938                        msm_write(port, val, UART_CR);
 939                        val = UART_CR_CMD_RESET_STALE_INT;
 940                        msm_write(port, val, UART_CR);
 941                        /*
 942                         * Flush DMA input fifo to memory, this will also
 943                         * trigger DMA RX completion
 944                         */
 945                        dmaengine_terminate_all(dma->chan);
 946                } else if (msm_port->is_uartdm) {
 947                        msm_handle_rx_dm(port, misr);
 948                } else {
 949                        msm_handle_rx(port);
 950                }
 951        }
 952        if (misr & UART_IMR_TXLEV)
 953                msm_handle_tx(port);
 954        if (misr & UART_IMR_DELTA_CTS)
 955                msm_handle_delta_cts(port);
 956
 957        msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
 958        spin_unlock_irqrestore(&port->lock, flags);
 959
 960        return IRQ_HANDLED;
 961}
 962
 963static unsigned int msm_tx_empty(struct uart_port *port)
 964{
 965        return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
 966}
 967
 968static unsigned int msm_get_mctrl(struct uart_port *port)
 969{
 970        return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 971}
 972
 973static void msm_reset(struct uart_port *port)
 974{
 975        struct msm_port *msm_port = UART_TO_MSM(port);
 976
 977        /* reset everything */
 978        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
 979        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 980        msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 981        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
 982        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 983        msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
 984
 985        /* Disable DM modes */
 986        if (msm_port->is_uartdm)
 987                msm_write(port, 0, UARTDM_DMEN);
 988}
 989
 990static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
 991{
 992        unsigned int mr;
 993
 994        mr = msm_read(port, UART_MR1);
 995
 996        if (!(mctrl & TIOCM_RTS)) {
 997                mr &= ~UART_MR1_RX_RDY_CTL;
 998                msm_write(port, mr, UART_MR1);
 999                msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1000        } else {
1001                mr |= UART_MR1_RX_RDY_CTL;
1002                msm_write(port, mr, UART_MR1);
1003        }
1004}
1005
1006static void msm_break_ctl(struct uart_port *port, int break_ctl)
1007{
1008        if (break_ctl)
1009                msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1010        else
1011                msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1012}
1013
1014struct msm_baud_map {
1015        u16     divisor;
1016        u8      code;
1017        u8      rxstale;
1018};
1019
1020static const struct msm_baud_map *
1021msm_find_best_baud(struct uart_port *port, unsigned int baud,
1022                   unsigned long *rate)
1023{
1024        struct msm_port *msm_port = UART_TO_MSM(port);
1025        unsigned int divisor, result;
1026        unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1027        const struct msm_baud_map *entry, *end, *best;
1028        static const struct msm_baud_map table[] = {
1029                {    1, 0xff, 31 },
1030                {    2, 0xee, 16 },
1031                {    3, 0xdd,  8 },
1032                {    4, 0xcc,  6 },
1033                {    6, 0xbb,  6 },
1034                {    8, 0xaa,  6 },
1035                {   12, 0x99,  6 },
1036                {   16, 0x88,  1 },
1037                {   24, 0x77,  1 },
1038                {   32, 0x66,  1 },
1039                {   48, 0x55,  1 },
1040                {   96, 0x44,  1 },
1041                {  192, 0x33,  1 },
1042                {  384, 0x22,  1 },
1043                {  768, 0x11,  1 },
1044                { 1536, 0x00,  1 },
1045        };
1046
1047        best = table; /* Default to smallest divider */
1048        target = clk_round_rate(msm_port->clk, 16 * baud);
1049        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1050
1051        end = table + ARRAY_SIZE(table);
1052        entry = table;
1053        while (entry < end) {
1054                if (entry->divisor <= divisor) {
1055                        result = target / entry->divisor / 16;
1056                        diff = abs(result - baud);
1057
1058                        /* Keep track of best entry */
1059                        if (diff < best_diff) {
1060                                best_diff = diff;
1061                                best = entry;
1062                                best_rate = target;
1063                        }
1064
1065                        if (result == baud)
1066                                break;
1067                } else if (entry->divisor > divisor) {
1068                        old = target;
1069                        target = clk_round_rate(msm_port->clk, old + 1);
1070                        /*
1071                         * The rate didn't get any faster so we can't do
1072                         * better at dividing it down
1073                         */
1074                        if (target == old)
1075                                break;
1076
1077                        /* Start the divisor search over at this new rate */
1078                        entry = table;
1079                        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1080                        continue;
1081                }
1082                entry++;
1083        }
1084
1085        *rate = best_rate;
1086        return best;
1087}
1088
1089static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1090                             unsigned long *saved_flags)
1091{
1092        unsigned int rxstale, watermark, mask;
1093        struct msm_port *msm_port = UART_TO_MSM(port);
1094        const struct msm_baud_map *entry;
1095        unsigned long flags, rate;
1096
1097        flags = *saved_flags;
1098        spin_unlock_irqrestore(&port->lock, flags);
1099
1100        entry = msm_find_best_baud(port, baud, &rate);
1101        clk_set_rate(msm_port->clk, rate);
1102        baud = rate / 16 / entry->divisor;
1103
1104        spin_lock_irqsave(&port->lock, flags);
1105        *saved_flags = flags;
1106        port->uartclk = rate;
1107
1108        msm_write(port, entry->code, UART_CSR);
1109
1110        /* RX stale watermark */
1111        rxstale = entry->rxstale;
1112        watermark = UART_IPR_STALE_LSB & rxstale;
1113        if (msm_port->is_uartdm) {
1114                mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1115        } else {
1116                watermark |= UART_IPR_RXSTALE_LAST;
1117                mask = UART_IPR_STALE_TIMEOUT_MSB;
1118        }
1119
1120        watermark |= mask & (rxstale << 2);
1121
1122        msm_write(port, watermark, UART_IPR);
1123
1124        /* set RX watermark */
1125        watermark = (port->fifosize * 3) / 4;
1126        msm_write(port, watermark, UART_RFWR);
1127
1128        /* set TX watermark */
1129        msm_write(port, 10, UART_TFWR);
1130
1131        msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1132        msm_reset(port);
1133
1134        /* Enable RX and TX */
1135        msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1136
1137        /* turn on RX and CTS interrupts */
1138        msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1139                        UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1140
1141        msm_write(port, msm_port->imr, UART_IMR);
1142
1143        if (msm_port->is_uartdm) {
1144                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1145                msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1146                msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1147        }
1148
1149        return baud;
1150}
1151
1152static void msm_init_clock(struct uart_port *port)
1153{
1154        struct msm_port *msm_port = UART_TO_MSM(port);
1155
1156        clk_prepare_enable(msm_port->clk);
1157        clk_prepare_enable(msm_port->pclk);
1158        msm_serial_set_mnd_regs(port);
1159}
1160
1161static int msm_startup(struct uart_port *port)
1162{
1163        struct msm_port *msm_port = UART_TO_MSM(port);
1164        unsigned int data, rfr_level, mask;
1165        int ret;
1166
1167        snprintf(msm_port->name, sizeof(msm_port->name),
1168                 "msm_serial%d", port->line);
1169
1170        msm_init_clock(port);
1171
1172        if (likely(port->fifosize > 12))
1173                rfr_level = port->fifosize - 12;
1174        else
1175                rfr_level = port->fifosize;
1176
1177        /* set automatic RFR level */
1178        data = msm_read(port, UART_MR1);
1179
1180        if (msm_port->is_uartdm)
1181                mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1182        else
1183                mask = UART_MR1_AUTO_RFR_LEVEL1;
1184
1185        data &= ~mask;
1186        data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1187        data |= mask & (rfr_level << 2);
1188        data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1189        msm_write(port, data, UART_MR1);
1190
1191        if (msm_port->is_uartdm) {
1192                msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1193                msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1194        }
1195
1196        ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1197                          msm_port->name, port);
1198        if (unlikely(ret))
1199                goto err_irq;
1200
1201        return 0;
1202
1203err_irq:
1204        if (msm_port->is_uartdm)
1205                msm_release_dma(msm_port);
1206
1207        clk_disable_unprepare(msm_port->pclk);
1208        clk_disable_unprepare(msm_port->clk);
1209
1210        return ret;
1211}
1212
1213static void msm_shutdown(struct uart_port *port)
1214{
1215        struct msm_port *msm_port = UART_TO_MSM(port);
1216
1217        msm_port->imr = 0;
1218        msm_write(port, 0, UART_IMR); /* disable interrupts */
1219
1220        if (msm_port->is_uartdm)
1221                msm_release_dma(msm_port);
1222
1223        clk_disable_unprepare(msm_port->clk);
1224
1225        free_irq(port->irq, port);
1226}
1227
1228static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1229                            struct ktermios *old)
1230{
1231        struct msm_port *msm_port = UART_TO_MSM(port);
1232        struct msm_dma *dma = &msm_port->rx_dma;
1233        unsigned long flags;
1234        unsigned int baud, mr;
1235
1236        spin_lock_irqsave(&port->lock, flags);
1237
1238        if (dma->chan) /* Terminate if any */
1239                msm_stop_dma(port, dma);
1240
1241        /* calculate and set baud rate */
1242        baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1243        baud = msm_set_baud_rate(port, baud, &flags);
1244        if (tty_termios_baud_rate(termios))
1245                tty_termios_encode_baud_rate(termios, baud, baud);
1246
1247        /* calculate parity */
1248        mr = msm_read(port, UART_MR2);
1249        mr &= ~UART_MR2_PARITY_MODE;
1250        if (termios->c_cflag & PARENB) {
1251                if (termios->c_cflag & PARODD)
1252                        mr |= UART_MR2_PARITY_MODE_ODD;
1253                else if (termios->c_cflag & CMSPAR)
1254                        mr |= UART_MR2_PARITY_MODE_SPACE;
1255                else
1256                        mr |= UART_MR2_PARITY_MODE_EVEN;
1257        }
1258
1259        /* calculate bits per char */
1260        mr &= ~UART_MR2_BITS_PER_CHAR;
1261        switch (termios->c_cflag & CSIZE) {
1262        case CS5:
1263                mr |= UART_MR2_BITS_PER_CHAR_5;
1264                break;
1265        case CS6:
1266                mr |= UART_MR2_BITS_PER_CHAR_6;
1267                break;
1268        case CS7:
1269                mr |= UART_MR2_BITS_PER_CHAR_7;
1270                break;
1271        case CS8:
1272        default:
1273                mr |= UART_MR2_BITS_PER_CHAR_8;
1274                break;
1275        }
1276
1277        /* calculate stop bits */
1278        mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1279        if (termios->c_cflag & CSTOPB)
1280                mr |= UART_MR2_STOP_BIT_LEN_TWO;
1281        else
1282                mr |= UART_MR2_STOP_BIT_LEN_ONE;
1283
1284        /* set parity, bits per char, and stop bit */
1285        msm_write(port, mr, UART_MR2);
1286
1287        /* calculate and set hardware flow control */
1288        mr = msm_read(port, UART_MR1);
1289        mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1290        if (termios->c_cflag & CRTSCTS) {
1291                mr |= UART_MR1_CTS_CTL;
1292                mr |= UART_MR1_RX_RDY_CTL;
1293        }
1294        msm_write(port, mr, UART_MR1);
1295
1296        /* Configure status bits to ignore based on termio flags. */
1297        port->read_status_mask = 0;
1298        if (termios->c_iflag & INPCK)
1299                port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1300        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1301                port->read_status_mask |= UART_SR_RX_BREAK;
1302
1303        uart_update_timeout(port, termios->c_cflag, baud);
1304
1305        /* Try to use DMA */
1306        msm_start_rx_dma(msm_port);
1307
1308        spin_unlock_irqrestore(&port->lock, flags);
1309}
1310
1311static const char *msm_type(struct uart_port *port)
1312{
1313        return "MSM";
1314}
1315
1316static void msm_release_port(struct uart_port *port)
1317{
1318        struct platform_device *pdev = to_platform_device(port->dev);
1319        struct resource *uart_resource;
1320        resource_size_t size;
1321
1322        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1323        if (unlikely(!uart_resource))
1324                return;
1325        size = resource_size(uart_resource);
1326
1327        release_mem_region(port->mapbase, size);
1328        iounmap(port->membase);
1329        port->membase = NULL;
1330}
1331
1332static int msm_request_port(struct uart_port *port)
1333{
1334        struct platform_device *pdev = to_platform_device(port->dev);
1335        struct resource *uart_resource;
1336        resource_size_t size;
1337        int ret;
1338
1339        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1340        if (unlikely(!uart_resource))
1341                return -ENXIO;
1342
1343        size = resource_size(uart_resource);
1344
1345        if (!request_mem_region(port->mapbase, size, "msm_serial"))
1346                return -EBUSY;
1347
1348        port->membase = ioremap(port->mapbase, size);
1349        if (!port->membase) {
1350                ret = -EBUSY;
1351                goto fail_release_port;
1352        }
1353
1354        return 0;
1355
1356fail_release_port:
1357        release_mem_region(port->mapbase, size);
1358        return ret;
1359}
1360
1361static void msm_config_port(struct uart_port *port, int flags)
1362{
1363        int ret;
1364
1365        if (flags & UART_CONFIG_TYPE) {
1366                port->type = PORT_MSM;
1367                ret = msm_request_port(port);
1368                if (ret)
1369                        return;
1370        }
1371}
1372
1373static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1374{
1375        if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1376                return -EINVAL;
1377        if (unlikely(port->irq != ser->irq))
1378                return -EINVAL;
1379        return 0;
1380}
1381
1382static void msm_power(struct uart_port *port, unsigned int state,
1383                      unsigned int oldstate)
1384{
1385        struct msm_port *msm_port = UART_TO_MSM(port);
1386
1387        switch (state) {
1388        case 0:
1389                clk_prepare_enable(msm_port->clk);
1390                clk_prepare_enable(msm_port->pclk);
1391                break;
1392        case 3:
1393                clk_disable_unprepare(msm_port->clk);
1394                clk_disable_unprepare(msm_port->pclk);
1395                break;
1396        default:
1397                pr_err("msm_serial: Unknown PM state %d\n", state);
1398        }
1399}
1400
1401#ifdef CONFIG_CONSOLE_POLL
1402static int msm_poll_get_char_single(struct uart_port *port)
1403{
1404        struct msm_port *msm_port = UART_TO_MSM(port);
1405        unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1406
1407        if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1408                return NO_POLL_CHAR;
1409
1410        return msm_read(port, rf_reg) & 0xff;
1411}
1412
1413static int msm_poll_get_char_dm(struct uart_port *port)
1414{
1415        int c;
1416        static u32 slop;
1417        static int count;
1418        unsigned char *sp = (unsigned char *)&slop;
1419
1420        /* Check if a previous read had more than one char */
1421        if (count) {
1422                c = sp[sizeof(slop) - count];
1423                count--;
1424        /* Or if FIFO is empty */
1425        } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1426                /*
1427                 * If RX packing buffer has less than a word, force stale to
1428                 * push contents into RX FIFO
1429                 */
1430                count = msm_read(port, UARTDM_RXFS);
1431                count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1432                if (count) {
1433                        msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1434                        slop = msm_read(port, UARTDM_RF);
1435                        c = sp[0];
1436                        count--;
1437                        msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1438                        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1439                        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1440                                  UART_CR);
1441                } else {
1442                        c = NO_POLL_CHAR;
1443                }
1444        /* FIFO has a word */
1445        } else {
1446                slop = msm_read(port, UARTDM_RF);
1447                c = sp[0];
1448                count = sizeof(slop) - 1;
1449        }
1450
1451        return c;
1452}
1453
1454static int msm_poll_get_char(struct uart_port *port)
1455{
1456        u32 imr;
1457        int c;
1458        struct msm_port *msm_port = UART_TO_MSM(port);
1459
1460        /* Disable all interrupts */
1461        imr = msm_read(port, UART_IMR);
1462        msm_write(port, 0, UART_IMR);
1463
1464        if (msm_port->is_uartdm)
1465                c = msm_poll_get_char_dm(port);
1466        else
1467                c = msm_poll_get_char_single(port);
1468
1469        /* Enable interrupts */
1470        msm_write(port, imr, UART_IMR);
1471
1472        return c;
1473}
1474
1475static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1476{
1477        u32 imr;
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                msm_reset_dm_count(port, 1);
1486
1487        /* Wait until FIFO is empty */
1488        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1489                cpu_relax();
1490
1491        /* Write a character */
1492        msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1493
1494        /* Wait until FIFO is empty */
1495        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1496                cpu_relax();
1497
1498        /* Enable interrupts */
1499        msm_write(port, imr, UART_IMR);
1500}
1501#endif
1502
1503static struct uart_ops msm_uart_pops = {
1504        .tx_empty = msm_tx_empty,
1505        .set_mctrl = msm_set_mctrl,
1506        .get_mctrl = msm_get_mctrl,
1507        .stop_tx = msm_stop_tx,
1508        .start_tx = msm_start_tx,
1509        .stop_rx = msm_stop_rx,
1510        .enable_ms = msm_enable_ms,
1511        .break_ctl = msm_break_ctl,
1512        .startup = msm_startup,
1513        .shutdown = msm_shutdown,
1514        .set_termios = msm_set_termios,
1515        .type = msm_type,
1516        .release_port = msm_release_port,
1517        .request_port = msm_request_port,
1518        .config_port = msm_config_port,
1519        .verify_port = msm_verify_port,
1520        .pm = msm_power,
1521#ifdef CONFIG_CONSOLE_POLL
1522        .poll_get_char  = msm_poll_get_char,
1523        .poll_put_char  = msm_poll_put_char,
1524#endif
1525};
1526
1527static struct msm_port msm_uart_ports[] = {
1528        {
1529                .uart = {
1530                        .iotype = UPIO_MEM,
1531                        .ops = &msm_uart_pops,
1532                        .flags = UPF_BOOT_AUTOCONF,
1533                        .fifosize = 64,
1534                        .line = 0,
1535                },
1536        },
1537        {
1538                .uart = {
1539                        .iotype = UPIO_MEM,
1540                        .ops = &msm_uart_pops,
1541                        .flags = UPF_BOOT_AUTOCONF,
1542                        .fifosize = 64,
1543                        .line = 1,
1544                },
1545        },
1546        {
1547                .uart = {
1548                        .iotype = UPIO_MEM,
1549                        .ops = &msm_uart_pops,
1550                        .flags = UPF_BOOT_AUTOCONF,
1551                        .fifosize = 64,
1552                        .line = 2,
1553                },
1554        },
1555};
1556
1557#define UART_NR ARRAY_SIZE(msm_uart_ports)
1558
1559static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1560{
1561        return &msm_uart_ports[line].uart;
1562}
1563
1564#ifdef CONFIG_SERIAL_MSM_CONSOLE
1565static void __msm_console_write(struct uart_port *port, const char *s,
1566                                unsigned int count, bool is_uartdm)
1567{
1568        int i;
1569        int num_newlines = 0;
1570        bool replaced = false;
1571        void __iomem *tf;
1572
1573        if (is_uartdm)
1574                tf = port->membase + UARTDM_TF;
1575        else
1576                tf = port->membase + UART_TF;
1577
1578        /* Account for newlines that will get a carriage return added */
1579        for (i = 0; i < count; i++)
1580                if (s[i] == '\n')
1581                        num_newlines++;
1582        count += num_newlines;
1583
1584        spin_lock(&port->lock);
1585        if (is_uartdm)
1586                msm_reset_dm_count(port, count);
1587
1588        i = 0;
1589        while (i < count) {
1590                int j;
1591                unsigned int num_chars;
1592                char buf[4] = { 0 };
1593
1594                if (is_uartdm)
1595                        num_chars = min(count - i, (unsigned int)sizeof(buf));
1596                else
1597                        num_chars = 1;
1598
1599                for (j = 0; j < num_chars; j++) {
1600                        char c = *s;
1601
1602                        if (c == '\n' && !replaced) {
1603                                buf[j] = '\r';
1604                                j++;
1605                                replaced = true;
1606                        }
1607                        if (j < num_chars) {
1608                                buf[j] = c;
1609                                s++;
1610                                replaced = false;
1611                        }
1612                }
1613
1614                while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1615                        cpu_relax();
1616
1617                iowrite32_rep(tf, buf, 1);
1618                i += num_chars;
1619        }
1620        spin_unlock(&port->lock);
1621}
1622
1623static void msm_console_write(struct console *co, const char *s,
1624                              unsigned int count)
1625{
1626        struct uart_port *port;
1627        struct msm_port *msm_port;
1628
1629        BUG_ON(co->index < 0 || co->index >= UART_NR);
1630
1631        port = msm_get_port_from_line(co->index);
1632        msm_port = UART_TO_MSM(port);
1633
1634        __msm_console_write(port, s, count, msm_port->is_uartdm);
1635}
1636
1637static int __init msm_console_setup(struct console *co, char *options)
1638{
1639        struct uart_port *port;
1640        int baud = 115200;
1641        int bits = 8;
1642        int parity = 'n';
1643        int flow = 'n';
1644
1645        if (unlikely(co->index >= UART_NR || co->index < 0))
1646                return -ENXIO;
1647
1648        port = msm_get_port_from_line(co->index);
1649
1650        if (unlikely(!port->membase))
1651                return -ENXIO;
1652
1653        msm_init_clock(port);
1654
1655        if (options)
1656                uart_parse_options(options, &baud, &parity, &bits, &flow);
1657
1658        pr_info("msm_serial: console setup on port #%d\n", port->line);
1659
1660        return uart_set_options(port, co, baud, parity, bits, flow);
1661}
1662
1663static void
1664msm_serial_early_write(struct console *con, const char *s, unsigned n)
1665{
1666        struct earlycon_device *dev = con->data;
1667
1668        __msm_console_write(&dev->port, s, n, false);
1669}
1670
1671static int __init
1672msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1673{
1674        if (!device->port.membase)
1675                return -ENODEV;
1676
1677        device->con->write = msm_serial_early_write;
1678        return 0;
1679}
1680OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1681                    msm_serial_early_console_setup);
1682
1683static void
1684msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1685{
1686        struct earlycon_device *dev = con->data;
1687
1688        __msm_console_write(&dev->port, s, n, true);
1689}
1690
1691static int __init
1692msm_serial_early_console_setup_dm(struct earlycon_device *device,
1693                                  const char *opt)
1694{
1695        if (!device->port.membase)
1696                return -ENODEV;
1697
1698        device->con->write = msm_serial_early_write_dm;
1699        return 0;
1700}
1701OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1702                    msm_serial_early_console_setup_dm);
1703
1704static struct uart_driver msm_uart_driver;
1705
1706static struct console msm_console = {
1707        .name = "ttyMSM",
1708        .write = msm_console_write,
1709        .device = uart_console_device,
1710        .setup = msm_console_setup,
1711        .flags = CON_PRINTBUFFER,
1712        .index = -1,
1713        .data = &msm_uart_driver,
1714};
1715
1716#define MSM_CONSOLE     (&msm_console)
1717
1718#else
1719#define MSM_CONSOLE     NULL
1720#endif
1721
1722static struct uart_driver msm_uart_driver = {
1723        .owner = THIS_MODULE,
1724        .driver_name = "msm_serial",
1725        .dev_name = "ttyMSM",
1726        .nr = UART_NR,
1727        .cons = MSM_CONSOLE,
1728};
1729
1730static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1731
1732static const struct of_device_id msm_uartdm_table[] = {
1733        { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1734        { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1735        { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1736        { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1737        { }
1738};
1739
1740static int msm_serial_probe(struct platform_device *pdev)
1741{
1742        struct msm_port *msm_port;
1743        struct resource *resource;
1744        struct uart_port *port;
1745        const struct of_device_id *id;
1746        int irq, line;
1747
1748        if (pdev->dev.of_node)
1749                line = of_alias_get_id(pdev->dev.of_node, "serial");
1750        else
1751                line = pdev->id;
1752
1753        if (line < 0)
1754                line = atomic_inc_return(&msm_uart_next_id) - 1;
1755
1756        if (unlikely(line < 0 || line >= UART_NR))
1757                return -ENXIO;
1758
1759        dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1760
1761        port = msm_get_port_from_line(line);
1762        port->dev = &pdev->dev;
1763        msm_port = UART_TO_MSM(port);
1764
1765        id = of_match_device(msm_uartdm_table, &pdev->dev);
1766        if (id)
1767                msm_port->is_uartdm = (unsigned long)id->data;
1768        else
1769                msm_port->is_uartdm = 0;
1770
1771        msm_port->clk = devm_clk_get(&pdev->dev, "core");
1772        if (IS_ERR(msm_port->clk))
1773                return PTR_ERR(msm_port->clk);
1774
1775        if (msm_port->is_uartdm) {
1776                msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1777                if (IS_ERR(msm_port->pclk))
1778                        return PTR_ERR(msm_port->pclk);
1779        }
1780
1781        port->uartclk = clk_get_rate(msm_port->clk);
1782        dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1783
1784        resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1785        if (unlikely(!resource))
1786                return -ENXIO;
1787        port->mapbase = resource->start;
1788
1789        irq = platform_get_irq(pdev, 0);
1790        if (unlikely(irq < 0))
1791                return -ENXIO;
1792        port->irq = irq;
1793
1794        platform_set_drvdata(pdev, port);
1795
1796        return uart_add_one_port(&msm_uart_driver, port);
1797}
1798
1799static int msm_serial_remove(struct platform_device *pdev)
1800{
1801        struct uart_port *port = platform_get_drvdata(pdev);
1802
1803        uart_remove_one_port(&msm_uart_driver, port);
1804
1805        return 0;
1806}
1807
1808static const struct of_device_id msm_match_table[] = {
1809        { .compatible = "qcom,msm-uart" },
1810        { .compatible = "qcom,msm-uartdm" },
1811        {}
1812};
1813MODULE_DEVICE_TABLE(of, msm_match_table);
1814
1815static int __maybe_unused msm_serial_suspend(struct device *dev)
1816{
1817        struct msm_port *port = dev_get_drvdata(dev);
1818
1819        uart_suspend_port(&msm_uart_driver, &port->uart);
1820
1821        return 0;
1822}
1823
1824static int __maybe_unused msm_serial_resume(struct device *dev)
1825{
1826        struct msm_port *port = dev_get_drvdata(dev);
1827
1828        uart_resume_port(&msm_uart_driver, &port->uart);
1829
1830        return 0;
1831}
1832
1833static const struct dev_pm_ops msm_serial_dev_pm_ops = {
1834        SET_SYSTEM_SLEEP_PM_OPS(msm_serial_suspend, msm_serial_resume)
1835};
1836
1837static struct platform_driver msm_platform_driver = {
1838        .remove = msm_serial_remove,
1839        .probe = msm_serial_probe,
1840        .driver = {
1841                .name = "msm_serial",
1842                .pm = &msm_serial_dev_pm_ops,
1843                .of_match_table = msm_match_table,
1844        },
1845};
1846
1847static int __init msm_serial_init(void)
1848{
1849        int ret;
1850
1851        ret = uart_register_driver(&msm_uart_driver);
1852        if (unlikely(ret))
1853                return ret;
1854
1855        ret = platform_driver_register(&msm_platform_driver);
1856        if (unlikely(ret))
1857                uart_unregister_driver(&msm_uart_driver);
1858
1859        pr_info("msm_serial: driver initialized\n");
1860
1861        return ret;
1862}
1863
1864static void __exit msm_serial_exit(void)
1865{
1866        platform_driver_unregister(&msm_platform_driver);
1867        uart_unregister_driver(&msm_uart_driver);
1868}
1869
1870module_init(msm_serial_init);
1871module_exit(msm_serial_exit);
1872
1873MODULE_AUTHOR("Robert Love <rlove@google.com>");
1874MODULE_DESCRIPTION("Driver for msm7x serial device");
1875MODULE_LICENSE("GPL");
1876