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        unsigned int timeout = 500000;
 387
 388        while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
 389                if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
 390                        break;
 391                udelay(1);
 392                if (!timeout--)
 393                        break;
 394        }
 395        msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);
 396}
 397
 398static void msm_stop_tx(struct uart_port *port)
 399{
 400        struct msm_port *msm_port = UART_TO_MSM(port);
 401
 402        msm_port->imr &= ~UART_IMR_TXLEV;
 403        msm_write(port, msm_port->imr, UART_IMR);
 404}
 405
 406static void msm_start_tx(struct uart_port *port)
 407{
 408        struct msm_port *msm_port = UART_TO_MSM(port);
 409        struct msm_dma *dma = &msm_port->tx_dma;
 410
 411        /* Already started in DMA mode */
 412        if (dma->count)
 413                return;
 414
 415        msm_port->imr |= UART_IMR_TXLEV;
 416        msm_write(port, msm_port->imr, UART_IMR);
 417}
 418
 419static void msm_reset_dm_count(struct uart_port *port, int count)
 420{
 421        msm_wait_for_xmitr(port);
 422        msm_write(port, count, UARTDM_NCF_TX);
 423        msm_read(port, UARTDM_NCF_TX);
 424}
 425
 426static void msm_complete_tx_dma(void *args)
 427{
 428        struct msm_port *msm_port = args;
 429        struct uart_port *port = &msm_port->uart;
 430        struct circ_buf *xmit = &port->state->xmit;
 431        struct msm_dma *dma = &msm_port->tx_dma;
 432        struct dma_tx_state state;
 433        enum dma_status status;
 434        unsigned long flags;
 435        unsigned int count;
 436        u32 val;
 437
 438        spin_lock_irqsave(&port->lock, flags);
 439
 440        /* Already stopped */
 441        if (!dma->count)
 442                goto done;
 443
 444        status = dmaengine_tx_status(dma->chan, dma->cookie, &state);
 445
 446        dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
 447
 448        val = msm_read(port, UARTDM_DMEN);
 449        val &= ~dma->enable_bit;
 450        msm_write(port, val, UARTDM_DMEN);
 451
 452        if (msm_port->is_uartdm > UARTDM_1P3) {
 453                msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 454                msm_write(port, UART_CR_TX_ENABLE, UART_CR);
 455        }
 456
 457        count = dma->count - state.residue;
 458        port->icount.tx += count;
 459        dma->count = 0;
 460
 461        xmit->tail += count;
 462        xmit->tail &= UART_XMIT_SIZE - 1;
 463
 464        /* Restore "Tx FIFO below watermark" interrupt */
 465        msm_port->imr |= UART_IMR_TXLEV;
 466        msm_write(port, msm_port->imr, UART_IMR);
 467
 468        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 469                uart_write_wakeup(port);
 470
 471        msm_handle_tx(port);
 472done:
 473        spin_unlock_irqrestore(&port->lock, flags);
 474}
 475
 476static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
 477{
 478        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 479        struct uart_port *port = &msm_port->uart;
 480        struct msm_dma *dma = &msm_port->tx_dma;
 481        void *cpu_addr;
 482        int ret;
 483        u32 val;
 484
 485        cpu_addr = &xmit->buf[xmit->tail];
 486
 487        dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
 488        ret = dma_mapping_error(port->dev, dma->phys);
 489        if (ret)
 490                return ret;
 491
 492        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 493                                                count, DMA_MEM_TO_DEV,
 494                                                DMA_PREP_INTERRUPT |
 495                                                DMA_PREP_FENCE);
 496        if (!dma->desc) {
 497                ret = -EIO;
 498                goto unmap;
 499        }
 500
 501        dma->desc->callback = msm_complete_tx_dma;
 502        dma->desc->callback_param = msm_port;
 503
 504        dma->cookie = dmaengine_submit(dma->desc);
 505        ret = dma_submit_error(dma->cookie);
 506        if (ret)
 507                goto unmap;
 508
 509        /*
 510         * Using DMA complete for Tx FIFO reload, no need for
 511         * "Tx FIFO below watermark" one, disable it
 512         */
 513        msm_port->imr &= ~UART_IMR_TXLEV;
 514        msm_write(port, msm_port->imr, UART_IMR);
 515
 516        dma->count = count;
 517
 518        val = msm_read(port, UARTDM_DMEN);
 519        val |= dma->enable_bit;
 520
 521        if (msm_port->is_uartdm < UARTDM_1P4)
 522                msm_write(port, val, UARTDM_DMEN);
 523
 524        msm_reset_dm_count(port, count);
 525
 526        if (msm_port->is_uartdm > UARTDM_1P3)
 527                msm_write(port, val, UARTDM_DMEN);
 528
 529        dma_async_issue_pending(dma->chan);
 530        return 0;
 531unmap:
 532        dma_unmap_single(port->dev, dma->phys, count, dma->dir);
 533        return ret;
 534}
 535
 536static void msm_complete_rx_dma(void *args)
 537{
 538        struct msm_port *msm_port = args;
 539        struct uart_port *port = &msm_port->uart;
 540        struct tty_port *tport = &port->state->port;
 541        struct msm_dma *dma = &msm_port->rx_dma;
 542        int count = 0, i, sysrq;
 543        unsigned long flags;
 544        u32 val;
 545
 546        spin_lock_irqsave(&port->lock, flags);
 547
 548        /* Already stopped */
 549        if (!dma->count)
 550                goto done;
 551
 552        val = msm_read(port, UARTDM_DMEN);
 553        val &= ~dma->enable_bit;
 554        msm_write(port, val, UARTDM_DMEN);
 555
 556        if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
 557                port->icount.overrun++;
 558                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 559                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 560        }
 561
 562        count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
 563
 564        port->icount.rx += count;
 565
 566        dma->count = 0;
 567
 568        dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 569
 570        for (i = 0; i < count; i++) {
 571                char flag = TTY_NORMAL;
 572
 573                if (msm_port->break_detected && dma->virt[i] == 0) {
 574                        port->icount.brk++;
 575                        flag = TTY_BREAK;
 576                        msm_port->break_detected = false;
 577                        if (uart_handle_break(port))
 578                                continue;
 579                }
 580
 581                if (!(port->read_status_mask & UART_SR_RX_BREAK))
 582                        flag = TTY_NORMAL;
 583
 584                spin_unlock_irqrestore(&port->lock, flags);
 585                sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
 586                spin_lock_irqsave(&port->lock, flags);
 587                if (!sysrq)
 588                        tty_insert_flip_char(tport, dma->virt[i], flag);
 589        }
 590
 591        msm_start_rx_dma(msm_port);
 592done:
 593        spin_unlock_irqrestore(&port->lock, flags);
 594
 595        if (count)
 596                tty_flip_buffer_push(tport);
 597}
 598
 599static void msm_start_rx_dma(struct msm_port *msm_port)
 600{
 601        struct msm_dma *dma = &msm_port->rx_dma;
 602        struct uart_port *uart = &msm_port->uart;
 603        u32 val;
 604        int ret;
 605
 606        if (!dma->chan)
 607                return;
 608
 609        dma->phys = dma_map_single(uart->dev, dma->virt,
 610                                   UARTDM_RX_SIZE, dma->dir);
 611        ret = dma_mapping_error(uart->dev, dma->phys);
 612        if (ret)
 613                return;
 614
 615        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 616                                                UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
 617                                                DMA_PREP_INTERRUPT);
 618        if (!dma->desc)
 619                goto unmap;
 620
 621        dma->desc->callback = msm_complete_rx_dma;
 622        dma->desc->callback_param = msm_port;
 623
 624        dma->cookie = dmaengine_submit(dma->desc);
 625        ret = dma_submit_error(dma->cookie);
 626        if (ret)
 627                goto unmap;
 628        /*
 629         * Using DMA for FIFO off-load, no need for "Rx FIFO over
 630         * watermark" or "stale" interrupts, disable them
 631         */
 632        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 633
 634        /*
 635         * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
 636         * we need RXSTALE to flush input DMA fifo to memory
 637         */
 638        if (msm_port->is_uartdm < UARTDM_1P4)
 639                msm_port->imr |= UART_IMR_RXSTALE;
 640
 641        msm_write(uart, msm_port->imr, UART_IMR);
 642
 643        dma->count = UARTDM_RX_SIZE;
 644
 645        dma_async_issue_pending(dma->chan);
 646
 647        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 648        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 649
 650        val = msm_read(uart, UARTDM_DMEN);
 651        val |= dma->enable_bit;
 652
 653        if (msm_port->is_uartdm < UARTDM_1P4)
 654                msm_write(uart, val, UARTDM_DMEN);
 655
 656        msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
 657
 658        if (msm_port->is_uartdm > UARTDM_1P3)
 659                msm_write(uart, val, UARTDM_DMEN);
 660
 661        return;
 662unmap:
 663        dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 664}
 665
 666static void msm_stop_rx(struct uart_port *port)
 667{
 668        struct msm_port *msm_port = UART_TO_MSM(port);
 669        struct msm_dma *dma = &msm_port->rx_dma;
 670
 671        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 672        msm_write(port, msm_port->imr, UART_IMR);
 673
 674        if (dma->chan)
 675                msm_stop_dma(port, dma);
 676}
 677
 678static void msm_enable_ms(struct uart_port *port)
 679{
 680        struct msm_port *msm_port = UART_TO_MSM(port);
 681
 682        msm_port->imr |= UART_IMR_DELTA_CTS;
 683        msm_write(port, msm_port->imr, UART_IMR);
 684}
 685
 686static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
 687{
 688        struct tty_port *tport = &port->state->port;
 689        unsigned int sr;
 690        int count = 0;
 691        struct msm_port *msm_port = UART_TO_MSM(port);
 692
 693        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 694                port->icount.overrun++;
 695                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 696                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 697        }
 698
 699        if (misr & UART_IMR_RXSTALE) {
 700                count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
 701                        msm_port->old_snap_state;
 702                msm_port->old_snap_state = 0;
 703        } else {
 704                count = 4 * (msm_read(port, UART_RFWR));
 705                msm_port->old_snap_state += count;
 706        }
 707
 708        /* TODO: Precise error reporting */
 709
 710        port->icount.rx += count;
 711
 712        while (count > 0) {
 713                unsigned char buf[4];
 714                int sysrq, r_count, i;
 715
 716                sr = msm_read(port, UART_SR);
 717                if ((sr & UART_SR_RX_READY) == 0) {
 718                        msm_port->old_snap_state -= count;
 719                        break;
 720                }
 721
 722                ioread32_rep(port->membase + UARTDM_RF, buf, 1);
 723                r_count = min_t(int, count, sizeof(buf));
 724
 725                for (i = 0; i < r_count; i++) {
 726                        char flag = TTY_NORMAL;
 727
 728                        if (msm_port->break_detected && buf[i] == 0) {
 729                                port->icount.brk++;
 730                                flag = TTY_BREAK;
 731                                msm_port->break_detected = false;
 732                                if (uart_handle_break(port))
 733                                        continue;
 734                        }
 735
 736                        if (!(port->read_status_mask & UART_SR_RX_BREAK))
 737                                flag = TTY_NORMAL;
 738
 739                        spin_unlock(&port->lock);
 740                        sysrq = uart_handle_sysrq_char(port, buf[i]);
 741                        spin_lock(&port->lock);
 742                        if (!sysrq)
 743                                tty_insert_flip_char(tport, buf[i], flag);
 744                }
 745                count -= r_count;
 746        }
 747
 748        spin_unlock(&port->lock);
 749        tty_flip_buffer_push(tport);
 750        spin_lock(&port->lock);
 751
 752        if (misr & (UART_IMR_RXSTALE))
 753                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 754        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
 755        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 756
 757        /* Try to use DMA */
 758        msm_start_rx_dma(msm_port);
 759}
 760
 761static void msm_handle_rx(struct uart_port *port)
 762{
 763        struct tty_port *tport = &port->state->port;
 764        unsigned int sr;
 765
 766        /*
 767         * Handle overrun. My understanding of the hardware is that overrun
 768         * is not tied to the RX buffer, so we handle the case out of band.
 769         */
 770        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 771                port->icount.overrun++;
 772                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 773                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 774        }
 775
 776        /* and now the main RX loop */
 777        while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
 778                unsigned int c;
 779                char flag = TTY_NORMAL;
 780                int sysrq;
 781
 782                c = msm_read(port, UART_RF);
 783
 784                if (sr & UART_SR_RX_BREAK) {
 785                        port->icount.brk++;
 786                        if (uart_handle_break(port))
 787                                continue;
 788                } else if (sr & UART_SR_PAR_FRAME_ERR) {
 789                        port->icount.frame++;
 790                } else {
 791                        port->icount.rx++;
 792                }
 793
 794                /* Mask conditions we're ignorning. */
 795                sr &= port->read_status_mask;
 796
 797                if (sr & UART_SR_RX_BREAK)
 798                        flag = TTY_BREAK;
 799                else if (sr & UART_SR_PAR_FRAME_ERR)
 800                        flag = TTY_FRAME;
 801
 802                spin_unlock(&port->lock);
 803                sysrq = uart_handle_sysrq_char(port, c);
 804                spin_lock(&port->lock);
 805                if (!sysrq)
 806                        tty_insert_flip_char(tport, c, flag);
 807        }
 808
 809        spin_unlock(&port->lock);
 810        tty_flip_buffer_push(tport);
 811        spin_lock(&port->lock);
 812}
 813
 814static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
 815{
 816        struct circ_buf *xmit = &port->state->xmit;
 817        struct msm_port *msm_port = UART_TO_MSM(port);
 818        unsigned int num_chars;
 819        unsigned int tf_pointer = 0;
 820        void __iomem *tf;
 821
 822        if (msm_port->is_uartdm)
 823                tf = port->membase + UARTDM_TF;
 824        else
 825                tf = port->membase + UART_TF;
 826
 827        if (tx_count && msm_port->is_uartdm)
 828                msm_reset_dm_count(port, tx_count);
 829
 830        while (tf_pointer < tx_count) {
 831                int i;
 832                char buf[4] = { 0 };
 833
 834                if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
 835                        break;
 836
 837                if (msm_port->is_uartdm)
 838                        num_chars = min(tx_count - tf_pointer,
 839                                        (unsigned int)sizeof(buf));
 840                else
 841                        num_chars = 1;
 842
 843                for (i = 0; i < num_chars; i++) {
 844                        buf[i] = xmit->buf[xmit->tail + i];
 845                        port->icount.tx++;
 846                }
 847
 848                iowrite32_rep(tf, buf, 1);
 849                xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
 850                tf_pointer += num_chars;
 851        }
 852
 853        /* disable tx interrupts if nothing more to send */
 854        if (uart_circ_empty(xmit))
 855                msm_stop_tx(port);
 856
 857        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 858                uart_write_wakeup(port);
 859}
 860
 861static void msm_handle_tx(struct uart_port *port)
 862{
 863        struct msm_port *msm_port = UART_TO_MSM(port);
 864        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 865        struct msm_dma *dma = &msm_port->tx_dma;
 866        unsigned int pio_count, dma_count, dma_min;
 867        char buf[4] = { 0 };
 868        void __iomem *tf;
 869        int err = 0;
 870
 871        if (port->x_char) {
 872                if (msm_port->is_uartdm)
 873                        tf = port->membase + UARTDM_TF;
 874                else
 875                        tf = port->membase + UART_TF;
 876
 877                buf[0] = port->x_char;
 878
 879                if (msm_port->is_uartdm)
 880                        msm_reset_dm_count(port, 1);
 881
 882                iowrite32_rep(tf, buf, 1);
 883                port->icount.tx++;
 884                port->x_char = 0;
 885                return;
 886        }
 887
 888        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 889                msm_stop_tx(port);
 890                return;
 891        }
 892
 893        pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 894        dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 895
 896        dma_min = 1;    /* Always DMA */
 897        if (msm_port->is_uartdm > UARTDM_1P3) {
 898                dma_count = UARTDM_TX_AIGN(dma_count);
 899                dma_min = UARTDM_BURST_SIZE;
 900        } else {
 901                if (dma_count > UARTDM_TX_MAX)
 902                        dma_count = UARTDM_TX_MAX;
 903        }
 904
 905        if (pio_count > port->fifosize)
 906                pio_count = port->fifosize;
 907
 908        if (!dma->chan || dma_count < dma_min)
 909                msm_handle_tx_pio(port, pio_count);
 910        else
 911                err = msm_handle_tx_dma(msm_port, dma_count);
 912
 913        if (err)        /* fall back to PIO mode */
 914                msm_handle_tx_pio(port, pio_count);
 915}
 916
 917static void msm_handle_delta_cts(struct uart_port *port)
 918{
 919        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 920        port->icount.cts++;
 921        wake_up_interruptible(&port->state->port.delta_msr_wait);
 922}
 923
 924static irqreturn_t msm_uart_irq(int irq, void *dev_id)
 925{
 926        struct uart_port *port = dev_id;
 927        struct msm_port *msm_port = UART_TO_MSM(port);
 928        struct msm_dma *dma = &msm_port->rx_dma;
 929        unsigned long flags;
 930        unsigned int misr;
 931        u32 val;
 932
 933        spin_lock_irqsave(&port->lock, flags);
 934        misr = msm_read(port, UART_MISR);
 935        msm_write(port, 0, UART_IMR); /* disable interrupt */
 936
 937        if (misr & UART_IMR_RXBREAK_START) {
 938                msm_port->break_detected = true;
 939                msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
 940        }
 941
 942        if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
 943                if (dma->count) {
 944                        val = UART_CR_CMD_STALE_EVENT_DISABLE;
 945                        msm_write(port, val, UART_CR);
 946                        val = UART_CR_CMD_RESET_STALE_INT;
 947                        msm_write(port, val, UART_CR);
 948                        /*
 949                         * Flush DMA input fifo to memory, this will also
 950                         * trigger DMA RX completion
 951                         */
 952                        dmaengine_terminate_all(dma->chan);
 953                } else if (msm_port->is_uartdm) {
 954                        msm_handle_rx_dm(port, misr);
 955                } else {
 956                        msm_handle_rx(port);
 957                }
 958        }
 959        if (misr & UART_IMR_TXLEV)
 960                msm_handle_tx(port);
 961        if (misr & UART_IMR_DELTA_CTS)
 962                msm_handle_delta_cts(port);
 963
 964        msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
 965        spin_unlock_irqrestore(&port->lock, flags);
 966
 967        return IRQ_HANDLED;
 968}
 969
 970static unsigned int msm_tx_empty(struct uart_port *port)
 971{
 972        return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
 973}
 974
 975static unsigned int msm_get_mctrl(struct uart_port *port)
 976{
 977        return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 978}
 979
 980static void msm_reset(struct uart_port *port)
 981{
 982        struct msm_port *msm_port = UART_TO_MSM(port);
 983
 984        /* reset everything */
 985        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
 986        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 987        msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 988        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
 989        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 990        msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
 991
 992        /* Disable DM modes */
 993        if (msm_port->is_uartdm)
 994                msm_write(port, 0, UARTDM_DMEN);
 995}
 996
 997static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
 998{
 999        unsigned int mr;
1000
1001        mr = msm_read(port, UART_MR1);
1002
1003        if (!(mctrl & TIOCM_RTS)) {
1004                mr &= ~UART_MR1_RX_RDY_CTL;
1005                msm_write(port, mr, UART_MR1);
1006                msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1007        } else {
1008                mr |= UART_MR1_RX_RDY_CTL;
1009                msm_write(port, mr, UART_MR1);
1010        }
1011}
1012
1013static void msm_break_ctl(struct uart_port *port, int break_ctl)
1014{
1015        if (break_ctl)
1016                msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1017        else
1018                msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1019}
1020
1021struct msm_baud_map {
1022        u16     divisor;
1023        u8      code;
1024        u8      rxstale;
1025};
1026
1027static const struct msm_baud_map *
1028msm_find_best_baud(struct uart_port *port, unsigned int baud,
1029                   unsigned long *rate)
1030{
1031        struct msm_port *msm_port = UART_TO_MSM(port);
1032        unsigned int divisor, result;
1033        unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1034        const struct msm_baud_map *entry, *end, *best;
1035        static const struct msm_baud_map table[] = {
1036                {    1, 0xff, 31 },
1037                {    2, 0xee, 16 },
1038                {    3, 0xdd,  8 },
1039                {    4, 0xcc,  6 },
1040                {    6, 0xbb,  6 },
1041                {    8, 0xaa,  6 },
1042                {   12, 0x99,  6 },
1043                {   16, 0x88,  1 },
1044                {   24, 0x77,  1 },
1045                {   32, 0x66,  1 },
1046                {   48, 0x55,  1 },
1047                {   96, 0x44,  1 },
1048                {  192, 0x33,  1 },
1049                {  384, 0x22,  1 },
1050                {  768, 0x11,  1 },
1051                { 1536, 0x00,  1 },
1052        };
1053
1054        best = table; /* Default to smallest divider */
1055        target = clk_round_rate(msm_port->clk, 16 * baud);
1056        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1057
1058        end = table + ARRAY_SIZE(table);
1059        entry = table;
1060        while (entry < end) {
1061                if (entry->divisor <= divisor) {
1062                        result = target / entry->divisor / 16;
1063                        diff = abs(result - baud);
1064
1065                        /* Keep track of best entry */
1066                        if (diff < best_diff) {
1067                                best_diff = diff;
1068                                best = entry;
1069                                best_rate = target;
1070                        }
1071
1072                        if (result == baud)
1073                                break;
1074                } else if (entry->divisor > divisor) {
1075                        old = target;
1076                        target = clk_round_rate(msm_port->clk, old + 1);
1077                        /*
1078                         * The rate didn't get any faster so we can't do
1079                         * better at dividing it down
1080                         */
1081                        if (target == old)
1082                                break;
1083
1084                        /* Start the divisor search over at this new rate */
1085                        entry = table;
1086                        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1087                        continue;
1088                }
1089                entry++;
1090        }
1091
1092        *rate = best_rate;
1093        return best;
1094}
1095
1096static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1097                             unsigned long *saved_flags)
1098{
1099        unsigned int rxstale, watermark, mask;
1100        struct msm_port *msm_port = UART_TO_MSM(port);
1101        const struct msm_baud_map *entry;
1102        unsigned long flags, rate;
1103
1104        flags = *saved_flags;
1105        spin_unlock_irqrestore(&port->lock, flags);
1106
1107        entry = msm_find_best_baud(port, baud, &rate);
1108        clk_set_rate(msm_port->clk, rate);
1109        baud = rate / 16 / entry->divisor;
1110
1111        spin_lock_irqsave(&port->lock, flags);
1112        *saved_flags = flags;
1113        port->uartclk = rate;
1114
1115        msm_write(port, entry->code, UART_CSR);
1116
1117        /* RX stale watermark */
1118        rxstale = entry->rxstale;
1119        watermark = UART_IPR_STALE_LSB & rxstale;
1120        if (msm_port->is_uartdm) {
1121                mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1122        } else {
1123                watermark |= UART_IPR_RXSTALE_LAST;
1124                mask = UART_IPR_STALE_TIMEOUT_MSB;
1125        }
1126
1127        watermark |= mask & (rxstale << 2);
1128
1129        msm_write(port, watermark, UART_IPR);
1130
1131        /* set RX watermark */
1132        watermark = (port->fifosize * 3) / 4;
1133        msm_write(port, watermark, UART_RFWR);
1134
1135        /* set TX watermark */
1136        msm_write(port, 10, UART_TFWR);
1137
1138        msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1139        msm_reset(port);
1140
1141        /* Enable RX and TX */
1142        msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1143
1144        /* turn on RX and CTS interrupts */
1145        msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1146                        UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1147
1148        msm_write(port, msm_port->imr, UART_IMR);
1149
1150        if (msm_port->is_uartdm) {
1151                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1152                msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1153                msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1154        }
1155
1156        return baud;
1157}
1158
1159static void msm_init_clock(struct uart_port *port)
1160{
1161        struct msm_port *msm_port = UART_TO_MSM(port);
1162
1163        clk_prepare_enable(msm_port->clk);
1164        clk_prepare_enable(msm_port->pclk);
1165        msm_serial_set_mnd_regs(port);
1166}
1167
1168static int msm_startup(struct uart_port *port)
1169{
1170        struct msm_port *msm_port = UART_TO_MSM(port);
1171        unsigned int data, rfr_level, mask;
1172        int ret;
1173
1174        snprintf(msm_port->name, sizeof(msm_port->name),
1175                 "msm_serial%d", port->line);
1176
1177        msm_init_clock(port);
1178
1179        if (likely(port->fifosize > 12))
1180                rfr_level = port->fifosize - 12;
1181        else
1182                rfr_level = port->fifosize;
1183
1184        /* set automatic RFR level */
1185        data = msm_read(port, UART_MR1);
1186
1187        if (msm_port->is_uartdm)
1188                mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1189        else
1190                mask = UART_MR1_AUTO_RFR_LEVEL1;
1191
1192        data &= ~mask;
1193        data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1194        data |= mask & (rfr_level << 2);
1195        data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1196        msm_write(port, data, UART_MR1);
1197
1198        if (msm_port->is_uartdm) {
1199                msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1200                msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1201        }
1202
1203        ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1204                          msm_port->name, port);
1205        if (unlikely(ret))
1206                goto err_irq;
1207
1208        return 0;
1209
1210err_irq:
1211        if (msm_port->is_uartdm)
1212                msm_release_dma(msm_port);
1213
1214        clk_disable_unprepare(msm_port->pclk);
1215        clk_disable_unprepare(msm_port->clk);
1216
1217        return ret;
1218}
1219
1220static void msm_shutdown(struct uart_port *port)
1221{
1222        struct msm_port *msm_port = UART_TO_MSM(port);
1223
1224        msm_port->imr = 0;
1225        msm_write(port, 0, UART_IMR); /* disable interrupts */
1226
1227        if (msm_port->is_uartdm)
1228                msm_release_dma(msm_port);
1229
1230        clk_disable_unprepare(msm_port->clk);
1231
1232        free_irq(port->irq, port);
1233}
1234
1235static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1236                            struct ktermios *old)
1237{
1238        struct msm_port *msm_port = UART_TO_MSM(port);
1239        struct msm_dma *dma = &msm_port->rx_dma;
1240        unsigned long flags;
1241        unsigned int baud, mr;
1242
1243        spin_lock_irqsave(&port->lock, flags);
1244
1245        if (dma->chan) /* Terminate if any */
1246                msm_stop_dma(port, dma);
1247
1248        /* calculate and set baud rate */
1249        baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1250        baud = msm_set_baud_rate(port, baud, &flags);
1251        if (tty_termios_baud_rate(termios))
1252                tty_termios_encode_baud_rate(termios, baud, baud);
1253
1254        /* calculate parity */
1255        mr = msm_read(port, UART_MR2);
1256        mr &= ~UART_MR2_PARITY_MODE;
1257        if (termios->c_cflag & PARENB) {
1258                if (termios->c_cflag & PARODD)
1259                        mr |= UART_MR2_PARITY_MODE_ODD;
1260                else if (termios->c_cflag & CMSPAR)
1261                        mr |= UART_MR2_PARITY_MODE_SPACE;
1262                else
1263                        mr |= UART_MR2_PARITY_MODE_EVEN;
1264        }
1265
1266        /* calculate bits per char */
1267        mr &= ~UART_MR2_BITS_PER_CHAR;
1268        switch (termios->c_cflag & CSIZE) {
1269        case CS5:
1270                mr |= UART_MR2_BITS_PER_CHAR_5;
1271                break;
1272        case CS6:
1273                mr |= UART_MR2_BITS_PER_CHAR_6;
1274                break;
1275        case CS7:
1276                mr |= UART_MR2_BITS_PER_CHAR_7;
1277                break;
1278        case CS8:
1279        default:
1280                mr |= UART_MR2_BITS_PER_CHAR_8;
1281                break;
1282        }
1283
1284        /* calculate stop bits */
1285        mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1286        if (termios->c_cflag & CSTOPB)
1287                mr |= UART_MR2_STOP_BIT_LEN_TWO;
1288        else
1289                mr |= UART_MR2_STOP_BIT_LEN_ONE;
1290
1291        /* set parity, bits per char, and stop bit */
1292        msm_write(port, mr, UART_MR2);
1293
1294        /* calculate and set hardware flow control */
1295        mr = msm_read(port, UART_MR1);
1296        mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1297        if (termios->c_cflag & CRTSCTS) {
1298                mr |= UART_MR1_CTS_CTL;
1299                mr |= UART_MR1_RX_RDY_CTL;
1300        }
1301        msm_write(port, mr, UART_MR1);
1302
1303        /* Configure status bits to ignore based on termio flags. */
1304        port->read_status_mask = 0;
1305        if (termios->c_iflag & INPCK)
1306                port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1307        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1308                port->read_status_mask |= UART_SR_RX_BREAK;
1309
1310        uart_update_timeout(port, termios->c_cflag, baud);
1311
1312        /* Try to use DMA */
1313        msm_start_rx_dma(msm_port);
1314
1315        spin_unlock_irqrestore(&port->lock, flags);
1316}
1317
1318static const char *msm_type(struct uart_port *port)
1319{
1320        return "MSM";
1321}
1322
1323static void msm_release_port(struct uart_port *port)
1324{
1325        struct platform_device *pdev = to_platform_device(port->dev);
1326        struct resource *uart_resource;
1327        resource_size_t size;
1328
1329        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1330        if (unlikely(!uart_resource))
1331                return;
1332        size = resource_size(uart_resource);
1333
1334        release_mem_region(port->mapbase, size);
1335        iounmap(port->membase);
1336        port->membase = NULL;
1337}
1338
1339static int msm_request_port(struct uart_port *port)
1340{
1341        struct platform_device *pdev = to_platform_device(port->dev);
1342        struct resource *uart_resource;
1343        resource_size_t size;
1344        int ret;
1345
1346        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1347        if (unlikely(!uart_resource))
1348                return -ENXIO;
1349
1350        size = resource_size(uart_resource);
1351
1352        if (!request_mem_region(port->mapbase, size, "msm_serial"))
1353                return -EBUSY;
1354
1355        port->membase = ioremap(port->mapbase, size);
1356        if (!port->membase) {
1357                ret = -EBUSY;
1358                goto fail_release_port;
1359        }
1360
1361        return 0;
1362
1363fail_release_port:
1364        release_mem_region(port->mapbase, size);
1365        return ret;
1366}
1367
1368static void msm_config_port(struct uart_port *port, int flags)
1369{
1370        int ret;
1371
1372        if (flags & UART_CONFIG_TYPE) {
1373                port->type = PORT_MSM;
1374                ret = msm_request_port(port);
1375                if (ret)
1376                        return;
1377        }
1378}
1379
1380static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1381{
1382        if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1383                return -EINVAL;
1384        if (unlikely(port->irq != ser->irq))
1385                return -EINVAL;
1386        return 0;
1387}
1388
1389static void msm_power(struct uart_port *port, unsigned int state,
1390                      unsigned int oldstate)
1391{
1392        struct msm_port *msm_port = UART_TO_MSM(port);
1393
1394        switch (state) {
1395        case 0:
1396                clk_prepare_enable(msm_port->clk);
1397                clk_prepare_enable(msm_port->pclk);
1398                break;
1399        case 3:
1400                clk_disable_unprepare(msm_port->clk);
1401                clk_disable_unprepare(msm_port->pclk);
1402                break;
1403        default:
1404                pr_err("msm_serial: Unknown PM state %d\n", state);
1405        }
1406}
1407
1408#ifdef CONFIG_CONSOLE_POLL
1409static int msm_poll_get_char_single(struct uart_port *port)
1410{
1411        struct msm_port *msm_port = UART_TO_MSM(port);
1412        unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1413
1414        if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1415                return NO_POLL_CHAR;
1416
1417        return msm_read(port, rf_reg) & 0xff;
1418}
1419
1420static int msm_poll_get_char_dm(struct uart_port *port)
1421{
1422        int c;
1423        static u32 slop;
1424        static int count;
1425        unsigned char *sp = (unsigned char *)&slop;
1426
1427        /* Check if a previous read had more than one char */
1428        if (count) {
1429                c = sp[sizeof(slop) - count];
1430                count--;
1431        /* Or if FIFO is empty */
1432        } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1433                /*
1434                 * If RX packing buffer has less than a word, force stale to
1435                 * push contents into RX FIFO
1436                 */
1437                count = msm_read(port, UARTDM_RXFS);
1438                count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1439                if (count) {
1440                        msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1441                        slop = msm_read(port, UARTDM_RF);
1442                        c = sp[0];
1443                        count--;
1444                        msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1445                        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1446                        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1447                                  UART_CR);
1448                } else {
1449                        c = NO_POLL_CHAR;
1450                }
1451        /* FIFO has a word */
1452        } else {
1453                slop = msm_read(port, UARTDM_RF);
1454                c = sp[0];
1455                count = sizeof(slop) - 1;
1456        }
1457
1458        return c;
1459}
1460
1461static int msm_poll_get_char(struct uart_port *port)
1462{
1463        u32 imr;
1464        int c;
1465        struct msm_port *msm_port = UART_TO_MSM(port);
1466
1467        /* Disable all interrupts */
1468        imr = msm_read(port, UART_IMR);
1469        msm_write(port, 0, UART_IMR);
1470
1471        if (msm_port->is_uartdm)
1472                c = msm_poll_get_char_dm(port);
1473        else
1474                c = msm_poll_get_char_single(port);
1475
1476        /* Enable interrupts */
1477        msm_write(port, imr, UART_IMR);
1478
1479        return c;
1480}
1481
1482static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1483{
1484        u32 imr;
1485        struct msm_port *msm_port = UART_TO_MSM(port);
1486
1487        /* Disable all interrupts */
1488        imr = msm_read(port, UART_IMR);
1489        msm_write(port, 0, UART_IMR);
1490
1491        if (msm_port->is_uartdm)
1492                msm_reset_dm_count(port, 1);
1493
1494        /* Wait until FIFO is empty */
1495        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1496                cpu_relax();
1497
1498        /* Write a character */
1499        msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1500
1501        /* Wait until FIFO is empty */
1502        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1503                cpu_relax();
1504
1505        /* Enable interrupts */
1506        msm_write(port, imr, UART_IMR);
1507}
1508#endif
1509
1510static struct uart_ops msm_uart_pops = {
1511        .tx_empty = msm_tx_empty,
1512        .set_mctrl = msm_set_mctrl,
1513        .get_mctrl = msm_get_mctrl,
1514        .stop_tx = msm_stop_tx,
1515        .start_tx = msm_start_tx,
1516        .stop_rx = msm_stop_rx,
1517        .enable_ms = msm_enable_ms,
1518        .break_ctl = msm_break_ctl,
1519        .startup = msm_startup,
1520        .shutdown = msm_shutdown,
1521        .set_termios = msm_set_termios,
1522        .type = msm_type,
1523        .release_port = msm_release_port,
1524        .request_port = msm_request_port,
1525        .config_port = msm_config_port,
1526        .verify_port = msm_verify_port,
1527        .pm = msm_power,
1528#ifdef CONFIG_CONSOLE_POLL
1529        .poll_get_char  = msm_poll_get_char,
1530        .poll_put_char  = msm_poll_put_char,
1531#endif
1532};
1533
1534static struct msm_port msm_uart_ports[] = {
1535        {
1536                .uart = {
1537                        .iotype = UPIO_MEM,
1538                        .ops = &msm_uart_pops,
1539                        .flags = UPF_BOOT_AUTOCONF,
1540                        .fifosize = 64,
1541                        .line = 0,
1542                },
1543        },
1544        {
1545                .uart = {
1546                        .iotype = UPIO_MEM,
1547                        .ops = &msm_uart_pops,
1548                        .flags = UPF_BOOT_AUTOCONF,
1549                        .fifosize = 64,
1550                        .line = 1,
1551                },
1552        },
1553        {
1554                .uart = {
1555                        .iotype = UPIO_MEM,
1556                        .ops = &msm_uart_pops,
1557                        .flags = UPF_BOOT_AUTOCONF,
1558                        .fifosize = 64,
1559                        .line = 2,
1560                },
1561        },
1562};
1563
1564#define UART_NR ARRAY_SIZE(msm_uart_ports)
1565
1566static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1567{
1568        return &msm_uart_ports[line].uart;
1569}
1570
1571#ifdef CONFIG_SERIAL_MSM_CONSOLE
1572static void __msm_console_write(struct uart_port *port, const char *s,
1573                                unsigned int count, bool is_uartdm)
1574{
1575        int i;
1576        int num_newlines = 0;
1577        bool replaced = false;
1578        void __iomem *tf;
1579
1580        if (is_uartdm)
1581                tf = port->membase + UARTDM_TF;
1582        else
1583                tf = port->membase + UART_TF;
1584
1585        /* Account for newlines that will get a carriage return added */
1586        for (i = 0; i < count; i++)
1587                if (s[i] == '\n')
1588                        num_newlines++;
1589        count += num_newlines;
1590
1591        spin_lock(&port->lock);
1592        if (is_uartdm)
1593                msm_reset_dm_count(port, count);
1594
1595        i = 0;
1596        while (i < count) {
1597                int j;
1598                unsigned int num_chars;
1599                char buf[4] = { 0 };
1600
1601                if (is_uartdm)
1602                        num_chars = min(count - i, (unsigned int)sizeof(buf));
1603                else
1604                        num_chars = 1;
1605
1606                for (j = 0; j < num_chars; j++) {
1607                        char c = *s;
1608
1609                        if (c == '\n' && !replaced) {
1610                                buf[j] = '\r';
1611                                j++;
1612                                replaced = true;
1613                        }
1614                        if (j < num_chars) {
1615                                buf[j] = c;
1616                                s++;
1617                                replaced = false;
1618                        }
1619                }
1620
1621                while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1622                        cpu_relax();
1623
1624                iowrite32_rep(tf, buf, 1);
1625                i += num_chars;
1626        }
1627        spin_unlock(&port->lock);
1628}
1629
1630static void msm_console_write(struct console *co, const char *s,
1631                              unsigned int count)
1632{
1633        struct uart_port *port;
1634        struct msm_port *msm_port;
1635
1636        BUG_ON(co->index < 0 || co->index >= UART_NR);
1637
1638        port = msm_get_port_from_line(co->index);
1639        msm_port = UART_TO_MSM(port);
1640
1641        __msm_console_write(port, s, count, msm_port->is_uartdm);
1642}
1643
1644static int msm_console_setup(struct console *co, char *options)
1645{
1646        struct uart_port *port;
1647        int baud = 115200;
1648        int bits = 8;
1649        int parity = 'n';
1650        int flow = 'n';
1651
1652        if (unlikely(co->index >= UART_NR || co->index < 0))
1653                return -ENXIO;
1654
1655        port = msm_get_port_from_line(co->index);
1656
1657        if (unlikely(!port->membase))
1658                return -ENXIO;
1659
1660        msm_init_clock(port);
1661
1662        if (options)
1663                uart_parse_options(options, &baud, &parity, &bits, &flow);
1664
1665        pr_info("msm_serial: console setup on port #%d\n", port->line);
1666
1667        return uart_set_options(port, co, baud, parity, bits, flow);
1668}
1669
1670static void
1671msm_serial_early_write(struct console *con, const char *s, unsigned n)
1672{
1673        struct earlycon_device *dev = con->data;
1674
1675        __msm_console_write(&dev->port, s, n, false);
1676}
1677
1678static int __init
1679msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1680{
1681        if (!device->port.membase)
1682                return -ENODEV;
1683
1684        device->con->write = msm_serial_early_write;
1685        return 0;
1686}
1687OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1688                    msm_serial_early_console_setup);
1689
1690static void
1691msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1692{
1693        struct earlycon_device *dev = con->data;
1694
1695        __msm_console_write(&dev->port, s, n, true);
1696}
1697
1698static int __init
1699msm_serial_early_console_setup_dm(struct earlycon_device *device,
1700                                  const char *opt)
1701{
1702        if (!device->port.membase)
1703                return -ENODEV;
1704
1705        device->con->write = msm_serial_early_write_dm;
1706        return 0;
1707}
1708OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1709                    msm_serial_early_console_setup_dm);
1710
1711static struct uart_driver msm_uart_driver;
1712
1713static struct console msm_console = {
1714        .name = "ttyMSM",
1715        .write = msm_console_write,
1716        .device = uart_console_device,
1717        .setup = msm_console_setup,
1718        .flags = CON_PRINTBUFFER,
1719        .index = -1,
1720        .data = &msm_uart_driver,
1721};
1722
1723#define MSM_CONSOLE     (&msm_console)
1724
1725#else
1726#define MSM_CONSOLE     NULL
1727#endif
1728
1729static struct uart_driver msm_uart_driver = {
1730        .owner = THIS_MODULE,
1731        .driver_name = "msm_serial",
1732        .dev_name = "ttyMSM",
1733        .nr = UART_NR,
1734        .cons = MSM_CONSOLE,
1735};
1736
1737static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1738
1739static const struct of_device_id msm_uartdm_table[] = {
1740        { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1741        { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1742        { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1743        { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1744        { }
1745};
1746
1747static int msm_serial_probe(struct platform_device *pdev)
1748{
1749        struct msm_port *msm_port;
1750        struct resource *resource;
1751        struct uart_port *port;
1752        const struct of_device_id *id;
1753        int irq, line;
1754
1755        if (pdev->dev.of_node)
1756                line = of_alias_get_id(pdev->dev.of_node, "serial");
1757        else
1758                line = pdev->id;
1759
1760        if (line < 0)
1761                line = atomic_inc_return(&msm_uart_next_id) - 1;
1762
1763        if (unlikely(line < 0 || line >= UART_NR))
1764                return -ENXIO;
1765
1766        dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1767
1768        port = msm_get_port_from_line(line);
1769        port->dev = &pdev->dev;
1770        msm_port = UART_TO_MSM(port);
1771
1772        id = of_match_device(msm_uartdm_table, &pdev->dev);
1773        if (id)
1774                msm_port->is_uartdm = (unsigned long)id->data;
1775        else
1776                msm_port->is_uartdm = 0;
1777
1778        msm_port->clk = devm_clk_get(&pdev->dev, "core");
1779        if (IS_ERR(msm_port->clk))
1780                return PTR_ERR(msm_port->clk);
1781
1782        if (msm_port->is_uartdm) {
1783                msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1784                if (IS_ERR(msm_port->pclk))
1785                        return PTR_ERR(msm_port->pclk);
1786        }
1787
1788        port->uartclk = clk_get_rate(msm_port->clk);
1789        dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1790
1791        resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1792        if (unlikely(!resource))
1793                return -ENXIO;
1794        port->mapbase = resource->start;
1795
1796        irq = platform_get_irq(pdev, 0);
1797        if (unlikely(irq < 0))
1798                return -ENXIO;
1799        port->irq = irq;
1800
1801        platform_set_drvdata(pdev, port);
1802
1803        return uart_add_one_port(&msm_uart_driver, port);
1804}
1805
1806static int msm_serial_remove(struct platform_device *pdev)
1807{
1808        struct uart_port *port = platform_get_drvdata(pdev);
1809
1810        uart_remove_one_port(&msm_uart_driver, port);
1811
1812        return 0;
1813}
1814
1815static const struct of_device_id msm_match_table[] = {
1816        { .compatible = "qcom,msm-uart" },
1817        { .compatible = "qcom,msm-uartdm" },
1818        {}
1819};
1820MODULE_DEVICE_TABLE(of, msm_match_table);
1821
1822static int __maybe_unused msm_serial_suspend(struct device *dev)
1823{
1824        struct msm_port *port = dev_get_drvdata(dev);
1825
1826        uart_suspend_port(&msm_uart_driver, &port->uart);
1827
1828        return 0;
1829}
1830
1831static int __maybe_unused msm_serial_resume(struct device *dev)
1832{
1833        struct msm_port *port = dev_get_drvdata(dev);
1834
1835        uart_resume_port(&msm_uart_driver, &port->uart);
1836
1837        return 0;
1838}
1839
1840static const struct dev_pm_ops msm_serial_dev_pm_ops = {
1841        SET_SYSTEM_SLEEP_PM_OPS(msm_serial_suspend, msm_serial_resume)
1842};
1843
1844static struct platform_driver msm_platform_driver = {
1845        .remove = msm_serial_remove,
1846        .probe = msm_serial_probe,
1847        .driver = {
1848                .name = "msm_serial",
1849                .pm = &msm_serial_dev_pm_ops,
1850                .of_match_table = msm_match_table,
1851        },
1852};
1853
1854static int __init msm_serial_init(void)
1855{
1856        int ret;
1857
1858        ret = uart_register_driver(&msm_uart_driver);
1859        if (unlikely(ret))
1860                return ret;
1861
1862        ret = platform_driver_register(&msm_platform_driver);
1863        if (unlikely(ret))
1864                uart_unregister_driver(&msm_uart_driver);
1865
1866        pr_info("msm_serial: driver initialized\n");
1867
1868        return ret;
1869}
1870
1871static void __exit msm_serial_exit(void)
1872{
1873        platform_driver_unregister(&msm_platform_driver);
1874        uart_unregister_driver(&msm_uart_driver);
1875}
1876
1877module_init(msm_serial_init);
1878module_exit(msm_serial_exit);
1879
1880MODULE_AUTHOR("Robert Love <rlove@google.com>");
1881MODULE_DESCRIPTION("Driver for msm7x serial device");
1882MODULE_LICENSE("GPL");
1883