linux/drivers/tty/serial/msm_serial.c
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   1/*
   2 * Driver for msm7k serial device and console
   3 *
   4 * Copyright (C) 2007 Google, Inc.
   5 * Author: Robert Love <rlove@google.com>
   6 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
   7 *
   8 * This software is licensed under the terms of the GNU General Public
   9 * License version 2, as published by the Free Software Foundation, and
  10 * may be copied, distributed, and modified under those terms.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public License for more details.
  16 */
  17
  18#if defined(CONFIG_SERIAL_MSM_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  19# define SUPPORT_SYSRQ
  20#endif
  21
  22#include <linux/kernel.h>
  23#include <linux/atomic.h>
  24#include <linux/dma-mapping.h>
  25#include <linux/dmaengine.h>
  26#include <linux/module.h>
  27#include <linux/io.h>
  28#include <linux/ioport.h>
  29#include <linux/interrupt.h>
  30#include <linux/init.h>
  31#include <linux/console.h>
  32#include <linux/tty.h>
  33#include <linux/tty_flip.h>
  34#include <linux/serial_core.h>
  35#include <linux/slab.h>
  36#include <linux/clk.h>
  37#include <linux/platform_device.h>
  38#include <linux/delay.h>
  39#include <linux/of.h>
  40#include <linux/of_device.h>
  41#include <linux/wait.h>
  42
  43#define UART_MR1                        0x0000
  44
  45#define UART_MR1_AUTO_RFR_LEVEL0        0x3F
  46#define UART_MR1_AUTO_RFR_LEVEL1        0x3FF00
  47#define UART_DM_MR1_AUTO_RFR_LEVEL1     0xFFFFFF00
  48#define UART_MR1_RX_RDY_CTL             BIT(7)
  49#define UART_MR1_CTS_CTL                BIT(6)
  50
  51#define UART_MR2                        0x0004
  52#define UART_MR2_ERROR_MODE             BIT(6)
  53#define UART_MR2_BITS_PER_CHAR          0x30
  54#define UART_MR2_BITS_PER_CHAR_5        (0x0 << 4)
  55#define UART_MR2_BITS_PER_CHAR_6        (0x1 << 4)
  56#define UART_MR2_BITS_PER_CHAR_7        (0x2 << 4)
  57#define UART_MR2_BITS_PER_CHAR_8        (0x3 << 4)
  58#define UART_MR2_STOP_BIT_LEN_ONE       (0x1 << 2)
  59#define UART_MR2_STOP_BIT_LEN_TWO       (0x3 << 2)
  60#define UART_MR2_PARITY_MODE_NONE       0x0
  61#define UART_MR2_PARITY_MODE_ODD        0x1
  62#define UART_MR2_PARITY_MODE_EVEN       0x2
  63#define UART_MR2_PARITY_MODE_SPACE      0x3
  64#define UART_MR2_PARITY_MODE            0x3
  65
  66#define UART_CSR                        0x0008
  67
  68#define UART_TF                         0x000C
  69#define UARTDM_TF                       0x0070
  70
  71#define UART_CR                         0x0010
  72#define UART_CR_CMD_NULL                (0 << 4)
  73#define UART_CR_CMD_RESET_RX            (1 << 4)
  74#define UART_CR_CMD_RESET_TX            (2 << 4)
  75#define UART_CR_CMD_RESET_ERR           (3 << 4)
  76#define UART_CR_CMD_RESET_BREAK_INT     (4 << 4)
  77#define UART_CR_CMD_START_BREAK         (5 << 4)
  78#define UART_CR_CMD_STOP_BREAK          (6 << 4)
  79#define UART_CR_CMD_RESET_CTS           (7 << 4)
  80#define UART_CR_CMD_RESET_STALE_INT     (8 << 4)
  81#define UART_CR_CMD_PACKET_MODE         (9 << 4)
  82#define UART_CR_CMD_MODE_RESET          (12 << 4)
  83#define UART_CR_CMD_SET_RFR             (13 << 4)
  84#define UART_CR_CMD_RESET_RFR           (14 << 4)
  85#define UART_CR_CMD_PROTECTION_EN       (16 << 4)
  86#define UART_CR_CMD_STALE_EVENT_DISABLE (6 << 8)
  87#define UART_CR_CMD_STALE_EVENT_ENABLE  (80 << 4)
  88#define UART_CR_CMD_FORCE_STALE         (4 << 8)
  89#define UART_CR_CMD_RESET_TX_READY      (3 << 8)
  90#define UART_CR_TX_DISABLE              BIT(3)
  91#define UART_CR_TX_ENABLE               BIT(2)
  92#define UART_CR_RX_DISABLE              BIT(1)
  93#define UART_CR_RX_ENABLE               BIT(0)
  94#define UART_CR_CMD_RESET_RXBREAK_START ((1 << 11) | (2 << 4))
  95
  96#define UART_IMR                        0x0014
  97#define UART_IMR_TXLEV                  BIT(0)
  98#define UART_IMR_RXSTALE                BIT(3)
  99#define UART_IMR_RXLEV                  BIT(4)
 100#define UART_IMR_DELTA_CTS              BIT(5)
 101#define UART_IMR_CURRENT_CTS            BIT(6)
 102#define UART_IMR_RXBREAK_START          BIT(10)
 103
 104#define UART_IPR_RXSTALE_LAST           0x20
 105#define UART_IPR_STALE_LSB              0x1F
 106#define UART_IPR_STALE_TIMEOUT_MSB      0x3FF80
 107#define UART_DM_IPR_STALE_TIMEOUT_MSB   0xFFFFFF80
 108
 109#define UART_IPR                        0x0018
 110#define UART_TFWR                       0x001C
 111#define UART_RFWR                       0x0020
 112#define UART_HCR                        0x0024
 113
 114#define UART_MREG                       0x0028
 115#define UART_NREG                       0x002C
 116#define UART_DREG                       0x0030
 117#define UART_MNDREG                     0x0034
 118#define UART_IRDA                       0x0038
 119#define UART_MISR_MODE                  0x0040
 120#define UART_MISR_RESET                 0x0044
 121#define UART_MISR_EXPORT                0x0048
 122#define UART_MISR_VAL                   0x004C
 123#define UART_TEST_CTRL                  0x0050
 124
 125#define UART_SR                         0x0008
 126#define UART_SR_HUNT_CHAR               BIT(7)
 127#define UART_SR_RX_BREAK                BIT(6)
 128#define UART_SR_PAR_FRAME_ERR           BIT(5)
 129#define UART_SR_OVERRUN                 BIT(4)
 130#define UART_SR_TX_EMPTY                BIT(3)
 131#define UART_SR_TX_READY                BIT(2)
 132#define UART_SR_RX_FULL                 BIT(1)
 133#define UART_SR_RX_READY                BIT(0)
 134
 135#define UART_RF                         0x000C
 136#define UARTDM_RF                       0x0070
 137#define UART_MISR                       0x0010
 138#define UART_ISR                        0x0014
 139#define UART_ISR_TX_READY               BIT(7)
 140
 141#define UARTDM_RXFS                     0x50
 142#define UARTDM_RXFS_BUF_SHIFT           0x7
 143#define UARTDM_RXFS_BUF_MASK            0x7
 144
 145#define UARTDM_DMEN                     0x3C
 146#define UARTDM_DMEN_RX_SC_ENABLE        BIT(5)
 147#define UARTDM_DMEN_TX_SC_ENABLE        BIT(4)
 148
 149#define UARTDM_DMEN_TX_BAM_ENABLE       BIT(2)  /* UARTDM_1P4 */
 150#define UARTDM_DMEN_TX_DM_ENABLE        BIT(0)  /* < UARTDM_1P4 */
 151
 152#define UARTDM_DMEN_RX_BAM_ENABLE       BIT(3)  /* UARTDM_1P4 */
 153#define UARTDM_DMEN_RX_DM_ENABLE        BIT(1)  /* < UARTDM_1P4 */
 154
 155#define UARTDM_DMRX                     0x34
 156#define UARTDM_NCF_TX                   0x40
 157#define UARTDM_RX_TOTAL_SNAP            0x38
 158
 159#define UARTDM_BURST_SIZE               16   /* in bytes */
 160#define UARTDM_TX_AIGN(x)               ((x) & ~0x3) /* valid for > 1p3 */
 161#define UARTDM_TX_MAX                   256   /* in bytes, valid for <= 1p3 */
 162#define UARTDM_RX_SIZE                  (UART_XMIT_SIZE / 4)
 163
 164enum {
 165        UARTDM_1P1 = 1,
 166        UARTDM_1P2,
 167        UARTDM_1P3,
 168        UARTDM_1P4,
 169};
 170
 171struct msm_dma {
 172        struct dma_chan         *chan;
 173        enum dma_data_direction dir;
 174        dma_addr_t              phys;
 175        unsigned char           *virt;
 176        dma_cookie_t            cookie;
 177        u32                     enable_bit;
 178        unsigned int            count;
 179        struct dma_async_tx_descriptor  *desc;
 180};
 181
 182struct msm_port {
 183        struct uart_port        uart;
 184        char                    name[16];
 185        struct clk              *clk;
 186        struct clk              *pclk;
 187        unsigned int            imr;
 188        int                     is_uartdm;
 189        unsigned int            old_snap_state;
 190        bool                    break_detected;
 191        struct msm_dma          tx_dma;
 192        struct msm_dma          rx_dma;
 193};
 194
 195#define UART_TO_MSM(uart_port)  container_of(uart_port, struct msm_port, uart)
 196
 197static
 198void msm_write(struct uart_port *port, unsigned int val, unsigned int off)
 199{
 200        writel_relaxed(val, port->membase + off);
 201}
 202
 203static
 204unsigned int msm_read(struct uart_port *port, unsigned int off)
 205{
 206        return readl_relaxed(port->membase + off);
 207}
 208
 209/*
 210 * Setup the MND registers to use the TCXO clock.
 211 */
 212static void msm_serial_set_mnd_regs_tcxo(struct uart_port *port)
 213{
 214        msm_write(port, 0x06, UART_MREG);
 215        msm_write(port, 0xF1, UART_NREG);
 216        msm_write(port, 0x0F, UART_DREG);
 217        msm_write(port, 0x1A, UART_MNDREG);
 218        port->uartclk = 1843200;
 219}
 220
 221/*
 222 * Setup the MND registers to use the TCXO clock divided by 4.
 223 */
 224static void msm_serial_set_mnd_regs_tcxoby4(struct uart_port *port)
 225{
 226        msm_write(port, 0x18, UART_MREG);
 227        msm_write(port, 0xF6, UART_NREG);
 228        msm_write(port, 0x0F, UART_DREG);
 229        msm_write(port, 0x0A, UART_MNDREG);
 230        port->uartclk = 1843200;
 231}
 232
 233static void msm_serial_set_mnd_regs(struct uart_port *port)
 234{
 235        struct msm_port *msm_port = UART_TO_MSM(port);
 236
 237        /*
 238         * These registers don't exist so we change the clk input rate
 239         * on uartdm hardware instead
 240         */
 241        if (msm_port->is_uartdm)
 242                return;
 243
 244        if (port->uartclk == 19200000)
 245                msm_serial_set_mnd_regs_tcxo(port);
 246        else if (port->uartclk == 4800000)
 247                msm_serial_set_mnd_regs_tcxoby4(port);
 248}
 249
 250static void msm_handle_tx(struct uart_port *port);
 251static void msm_start_rx_dma(struct msm_port *msm_port);
 252
 253static void msm_stop_dma(struct uart_port *port, struct msm_dma *dma)
 254{
 255        struct device *dev = port->dev;
 256        unsigned int mapped;
 257        u32 val;
 258
 259        mapped = dma->count;
 260        dma->count = 0;
 261
 262        dmaengine_terminate_all(dma->chan);
 263
 264        /*
 265         * DMA Stall happens if enqueue and flush command happens concurrently.
 266         * For example before changing the baud rate/protocol configuration and
 267         * sending flush command to ADM, disable the channel of UARTDM.
 268         * Note: should not reset the receiver here immediately as it is not
 269         * suggested to do disable/reset or reset/disable at the same time.
 270         */
 271        val = msm_read(port, UARTDM_DMEN);
 272        val &= ~dma->enable_bit;
 273        msm_write(port, val, UARTDM_DMEN);
 274
 275        if (mapped)
 276                dma_unmap_single(dev, dma->phys, mapped, dma->dir);
 277}
 278
 279static void msm_release_dma(struct msm_port *msm_port)
 280{
 281        struct msm_dma *dma;
 282
 283        dma = &msm_port->tx_dma;
 284        if (dma->chan) {
 285                msm_stop_dma(&msm_port->uart, dma);
 286                dma_release_channel(dma->chan);
 287        }
 288
 289        memset(dma, 0, sizeof(*dma));
 290
 291        dma = &msm_port->rx_dma;
 292        if (dma->chan) {
 293                msm_stop_dma(&msm_port->uart, dma);
 294                dma_release_channel(dma->chan);
 295                kfree(dma->virt);
 296        }
 297
 298        memset(dma, 0, sizeof(*dma));
 299}
 300
 301static void msm_request_tx_dma(struct msm_port *msm_port, resource_size_t base)
 302{
 303        struct device *dev = msm_port->uart.dev;
 304        struct dma_slave_config conf;
 305        struct msm_dma *dma;
 306        u32 crci = 0;
 307        int ret;
 308
 309        dma = &msm_port->tx_dma;
 310
 311        /* allocate DMA resources, if available */
 312        dma->chan = dma_request_slave_channel_reason(dev, "tx");
 313        if (IS_ERR(dma->chan))
 314                goto no_tx;
 315
 316        of_property_read_u32(dev->of_node, "qcom,tx-crci", &crci);
 317
 318        memset(&conf, 0, sizeof(conf));
 319        conf.direction = DMA_MEM_TO_DEV;
 320        conf.device_fc = true;
 321        conf.dst_addr = base + UARTDM_TF;
 322        conf.dst_maxburst = UARTDM_BURST_SIZE;
 323        conf.slave_id = crci;
 324
 325        ret = dmaengine_slave_config(dma->chan, &conf);
 326        if (ret)
 327                goto rel_tx;
 328
 329        dma->dir = DMA_TO_DEVICE;
 330
 331        if (msm_port->is_uartdm < UARTDM_1P4)
 332                dma->enable_bit = UARTDM_DMEN_TX_DM_ENABLE;
 333        else
 334                dma->enable_bit = UARTDM_DMEN_TX_BAM_ENABLE;
 335
 336        return;
 337
 338rel_tx:
 339        dma_release_channel(dma->chan);
 340no_tx:
 341        memset(dma, 0, sizeof(*dma));
 342}
 343
 344static void msm_request_rx_dma(struct msm_port *msm_port, resource_size_t base)
 345{
 346        struct device *dev = msm_port->uart.dev;
 347        struct dma_slave_config conf;
 348        struct msm_dma *dma;
 349        u32 crci = 0;
 350        int ret;
 351
 352        dma = &msm_port->rx_dma;
 353
 354        /* allocate DMA resources, if available */
 355        dma->chan = dma_request_slave_channel_reason(dev, "rx");
 356        if (IS_ERR(dma->chan))
 357                goto no_rx;
 358
 359        of_property_read_u32(dev->of_node, "qcom,rx-crci", &crci);
 360
 361        dma->virt = kzalloc(UARTDM_RX_SIZE, GFP_KERNEL);
 362        if (!dma->virt)
 363                goto rel_rx;
 364
 365        memset(&conf, 0, sizeof(conf));
 366        conf.direction = DMA_DEV_TO_MEM;
 367        conf.device_fc = true;
 368        conf.src_addr = base + UARTDM_RF;
 369        conf.src_maxburst = UARTDM_BURST_SIZE;
 370        conf.slave_id = crci;
 371
 372        ret = dmaengine_slave_config(dma->chan, &conf);
 373        if (ret)
 374                goto err;
 375
 376        dma->dir = DMA_FROM_DEVICE;
 377
 378        if (msm_port->is_uartdm < UARTDM_1P4)
 379                dma->enable_bit = UARTDM_DMEN_RX_DM_ENABLE;
 380        else
 381                dma->enable_bit = UARTDM_DMEN_RX_BAM_ENABLE;
 382
 383        return;
 384err:
 385        kfree(dma->virt);
 386rel_rx:
 387        dma_release_channel(dma->chan);
 388no_rx:
 389        memset(dma, 0, sizeof(*dma));
 390}
 391
 392static inline void msm_wait_for_xmitr(struct uart_port *port)
 393{
 394        while (!(msm_read(port, UART_SR) & UART_SR_TX_EMPTY)) {
 395                if (msm_read(port, UART_ISR) & UART_ISR_TX_READY)
 396                        break;
 397                udelay(1);
 398        }
 399        msm_write(port, UART_CR_CMD_RESET_TX_READY, UART_CR);
 400}
 401
 402static void msm_stop_tx(struct uart_port *port)
 403{
 404        struct msm_port *msm_port = UART_TO_MSM(port);
 405
 406        msm_port->imr &= ~UART_IMR_TXLEV;
 407        msm_write(port, msm_port->imr, UART_IMR);
 408}
 409
 410static void msm_start_tx(struct uart_port *port)
 411{
 412        struct msm_port *msm_port = UART_TO_MSM(port);
 413        struct msm_dma *dma = &msm_port->tx_dma;
 414
 415        /* Already started in DMA mode */
 416        if (dma->count)
 417                return;
 418
 419        msm_port->imr |= UART_IMR_TXLEV;
 420        msm_write(port, msm_port->imr, UART_IMR);
 421}
 422
 423static void msm_reset_dm_count(struct uart_port *port, int count)
 424{
 425        msm_wait_for_xmitr(port);
 426        msm_write(port, count, UARTDM_NCF_TX);
 427        msm_read(port, UARTDM_NCF_TX);
 428}
 429
 430static void msm_complete_tx_dma(void *args)
 431{
 432        struct msm_port *msm_port = args;
 433        struct uart_port *port = &msm_port->uart;
 434        struct circ_buf *xmit = &port->state->xmit;
 435        struct msm_dma *dma = &msm_port->tx_dma;
 436        struct dma_tx_state state;
 437        enum dma_status status;
 438        unsigned long flags;
 439        unsigned int count;
 440        u32 val;
 441
 442        spin_lock_irqsave(&port->lock, flags);
 443
 444        /* Already stopped */
 445        if (!dma->count)
 446                goto done;
 447
 448        status = dmaengine_tx_status(dma->chan, dma->cookie, &state);
 449
 450        dma_unmap_single(port->dev, dma->phys, dma->count, dma->dir);
 451
 452        val = msm_read(port, UARTDM_DMEN);
 453        val &= ~dma->enable_bit;
 454        msm_write(port, val, UARTDM_DMEN);
 455
 456        if (msm_port->is_uartdm > UARTDM_1P3) {
 457                msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 458                msm_write(port, UART_CR_TX_ENABLE, UART_CR);
 459        }
 460
 461        count = dma->count - state.residue;
 462        port->icount.tx += count;
 463        dma->count = 0;
 464
 465        xmit->tail += count;
 466        xmit->tail &= UART_XMIT_SIZE - 1;
 467
 468        /* Restore "Tx FIFO below watermark" interrupt */
 469        msm_port->imr |= UART_IMR_TXLEV;
 470        msm_write(port, msm_port->imr, UART_IMR);
 471
 472        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 473                uart_write_wakeup(port);
 474
 475        msm_handle_tx(port);
 476done:
 477        spin_unlock_irqrestore(&port->lock, flags);
 478}
 479
 480static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
 481{
 482        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 483        struct uart_port *port = &msm_port->uart;
 484        struct msm_dma *dma = &msm_port->tx_dma;
 485        void *cpu_addr;
 486        int ret;
 487        u32 val;
 488
 489        cpu_addr = &xmit->buf[xmit->tail];
 490
 491        dma->phys = dma_map_single(port->dev, cpu_addr, count, dma->dir);
 492        ret = dma_mapping_error(port->dev, dma->phys);
 493        if (ret)
 494                return ret;
 495
 496        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 497                                                count, DMA_MEM_TO_DEV,
 498                                                DMA_PREP_INTERRUPT |
 499                                                DMA_PREP_FENCE);
 500        if (!dma->desc) {
 501                ret = -EIO;
 502                goto unmap;
 503        }
 504
 505        dma->desc->callback = msm_complete_tx_dma;
 506        dma->desc->callback_param = msm_port;
 507
 508        dma->cookie = dmaengine_submit(dma->desc);
 509        ret = dma_submit_error(dma->cookie);
 510        if (ret)
 511                goto unmap;
 512
 513        /*
 514         * Using DMA complete for Tx FIFO reload, no need for
 515         * "Tx FIFO below watermark" one, disable it
 516         */
 517        msm_port->imr &= ~UART_IMR_TXLEV;
 518        msm_write(port, msm_port->imr, UART_IMR);
 519
 520        dma->count = count;
 521
 522        val = msm_read(port, UARTDM_DMEN);
 523        val |= dma->enable_bit;
 524
 525        if (msm_port->is_uartdm < UARTDM_1P4)
 526                msm_write(port, val, UARTDM_DMEN);
 527
 528        msm_reset_dm_count(port, count);
 529
 530        if (msm_port->is_uartdm > UARTDM_1P3)
 531                msm_write(port, val, UARTDM_DMEN);
 532
 533        dma_async_issue_pending(dma->chan);
 534        return 0;
 535unmap:
 536        dma_unmap_single(port->dev, dma->phys, count, dma->dir);
 537        return ret;
 538}
 539
 540static void msm_complete_rx_dma(void *args)
 541{
 542        struct msm_port *msm_port = args;
 543        struct uart_port *port = &msm_port->uart;
 544        struct tty_port *tport = &port->state->port;
 545        struct msm_dma *dma = &msm_port->rx_dma;
 546        int count = 0, i, sysrq;
 547        unsigned long flags;
 548        u32 val;
 549
 550        spin_lock_irqsave(&port->lock, flags);
 551
 552        /* Already stopped */
 553        if (!dma->count)
 554                goto done;
 555
 556        val = msm_read(port, UARTDM_DMEN);
 557        val &= ~dma->enable_bit;
 558        msm_write(port, val, UARTDM_DMEN);
 559
 560        if (msm_read(port, UART_SR) & UART_SR_OVERRUN) {
 561                port->icount.overrun++;
 562                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 563                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 564        }
 565
 566        count = msm_read(port, UARTDM_RX_TOTAL_SNAP);
 567
 568        port->icount.rx += count;
 569
 570        dma->count = 0;
 571
 572        dma_unmap_single(port->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 573
 574        for (i = 0; i < count; i++) {
 575                char flag = TTY_NORMAL;
 576
 577                if (msm_port->break_detected && dma->virt[i] == 0) {
 578                        port->icount.brk++;
 579                        flag = TTY_BREAK;
 580                        msm_port->break_detected = false;
 581                        if (uart_handle_break(port))
 582                                continue;
 583                }
 584
 585                if (!(port->read_status_mask & UART_SR_RX_BREAK))
 586                        flag = TTY_NORMAL;
 587
 588                spin_unlock_irqrestore(&port->lock, flags);
 589                sysrq = uart_handle_sysrq_char(port, dma->virt[i]);
 590                spin_lock_irqsave(&port->lock, flags);
 591                if (!sysrq)
 592                        tty_insert_flip_char(tport, dma->virt[i], flag);
 593        }
 594
 595        msm_start_rx_dma(msm_port);
 596done:
 597        spin_unlock_irqrestore(&port->lock, flags);
 598
 599        if (count)
 600                tty_flip_buffer_push(tport);
 601}
 602
 603static void msm_start_rx_dma(struct msm_port *msm_port)
 604{
 605        struct msm_dma *dma = &msm_port->rx_dma;
 606        struct uart_port *uart = &msm_port->uart;
 607        u32 val;
 608        int ret;
 609
 610        if (!dma->chan)
 611                return;
 612
 613        dma->phys = dma_map_single(uart->dev, dma->virt,
 614                                   UARTDM_RX_SIZE, dma->dir);
 615        ret = dma_mapping_error(uart->dev, dma->phys);
 616        if (ret)
 617                return;
 618
 619        dma->desc = dmaengine_prep_slave_single(dma->chan, dma->phys,
 620                                                UARTDM_RX_SIZE, DMA_DEV_TO_MEM,
 621                                                DMA_PREP_INTERRUPT);
 622        if (!dma->desc)
 623                goto unmap;
 624
 625        dma->desc->callback = msm_complete_rx_dma;
 626        dma->desc->callback_param = msm_port;
 627
 628        dma->cookie = dmaengine_submit(dma->desc);
 629        ret = dma_submit_error(dma->cookie);
 630        if (ret)
 631                goto unmap;
 632        /*
 633         * Using DMA for FIFO off-load, no need for "Rx FIFO over
 634         * watermark" or "stale" interrupts, disable them
 635         */
 636        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 637
 638        /*
 639         * Well, when DMA is ADM3 engine(implied by <= UARTDM v1.3),
 640         * we need RXSTALE to flush input DMA fifo to memory
 641         */
 642        if (msm_port->is_uartdm < UARTDM_1P4)
 643                msm_port->imr |= UART_IMR_RXSTALE;
 644
 645        msm_write(uart, msm_port->imr, UART_IMR);
 646
 647        dma->count = UARTDM_RX_SIZE;
 648
 649        dma_async_issue_pending(dma->chan);
 650
 651        msm_write(uart, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 652        msm_write(uart, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 653
 654        val = msm_read(uart, UARTDM_DMEN);
 655        val |= dma->enable_bit;
 656
 657        if (msm_port->is_uartdm < UARTDM_1P4)
 658                msm_write(uart, val, UARTDM_DMEN);
 659
 660        msm_write(uart, UARTDM_RX_SIZE, UARTDM_DMRX);
 661
 662        if (msm_port->is_uartdm > UARTDM_1P3)
 663                msm_write(uart, val, UARTDM_DMEN);
 664
 665        return;
 666unmap:
 667        dma_unmap_single(uart->dev, dma->phys, UARTDM_RX_SIZE, dma->dir);
 668}
 669
 670static void msm_stop_rx(struct uart_port *port)
 671{
 672        struct msm_port *msm_port = UART_TO_MSM(port);
 673        struct msm_dma *dma = &msm_port->rx_dma;
 674
 675        msm_port->imr &= ~(UART_IMR_RXLEV | UART_IMR_RXSTALE);
 676        msm_write(port, msm_port->imr, UART_IMR);
 677
 678        if (dma->chan)
 679                msm_stop_dma(port, dma);
 680}
 681
 682static void msm_enable_ms(struct uart_port *port)
 683{
 684        struct msm_port *msm_port = UART_TO_MSM(port);
 685
 686        msm_port->imr |= UART_IMR_DELTA_CTS;
 687        msm_write(port, msm_port->imr, UART_IMR);
 688}
 689
 690static void msm_handle_rx_dm(struct uart_port *port, unsigned int misr)
 691{
 692        struct tty_port *tport = &port->state->port;
 693        unsigned int sr;
 694        int count = 0;
 695        struct msm_port *msm_port = UART_TO_MSM(port);
 696
 697        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 698                port->icount.overrun++;
 699                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 700                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 701        }
 702
 703        if (misr & UART_IMR_RXSTALE) {
 704                count = msm_read(port, UARTDM_RX_TOTAL_SNAP) -
 705                        msm_port->old_snap_state;
 706                msm_port->old_snap_state = 0;
 707        } else {
 708                count = 4 * (msm_read(port, UART_RFWR));
 709                msm_port->old_snap_state += count;
 710        }
 711
 712        /* TODO: Precise error reporting */
 713
 714        port->icount.rx += count;
 715
 716        while (count > 0) {
 717                unsigned char buf[4];
 718                int sysrq, r_count, i;
 719
 720                sr = msm_read(port, UART_SR);
 721                if ((sr & UART_SR_RX_READY) == 0) {
 722                        msm_port->old_snap_state -= count;
 723                        break;
 724                }
 725
 726                ioread32_rep(port->membase + UARTDM_RF, buf, 1);
 727                r_count = min_t(int, count, sizeof(buf));
 728
 729                for (i = 0; i < r_count; i++) {
 730                        char flag = TTY_NORMAL;
 731
 732                        if (msm_port->break_detected && buf[i] == 0) {
 733                                port->icount.brk++;
 734                                flag = TTY_BREAK;
 735                                msm_port->break_detected = false;
 736                                if (uart_handle_break(port))
 737                                        continue;
 738                        }
 739
 740                        if (!(port->read_status_mask & UART_SR_RX_BREAK))
 741                                flag = TTY_NORMAL;
 742
 743                        spin_unlock(&port->lock);
 744                        sysrq = uart_handle_sysrq_char(port, buf[i]);
 745                        spin_lock(&port->lock);
 746                        if (!sysrq)
 747                                tty_insert_flip_char(tport, buf[i], flag);
 748                }
 749                count -= r_count;
 750        }
 751
 752        spin_unlock(&port->lock);
 753        tty_flip_buffer_push(tport);
 754        spin_lock(&port->lock);
 755
 756        if (misr & (UART_IMR_RXSTALE))
 757                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
 758        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
 759        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
 760
 761        /* Try to use DMA */
 762        msm_start_rx_dma(msm_port);
 763}
 764
 765static void msm_handle_rx(struct uart_port *port)
 766{
 767        struct tty_port *tport = &port->state->port;
 768        unsigned int sr;
 769
 770        /*
 771         * Handle overrun. My understanding of the hardware is that overrun
 772         * is not tied to the RX buffer, so we handle the case out of band.
 773         */
 774        if ((msm_read(port, UART_SR) & UART_SR_OVERRUN)) {
 775                port->icount.overrun++;
 776                tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 777                msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 778        }
 779
 780        /* and now the main RX loop */
 781        while ((sr = msm_read(port, UART_SR)) & UART_SR_RX_READY) {
 782                unsigned int c;
 783                char flag = TTY_NORMAL;
 784                int sysrq;
 785
 786                c = msm_read(port, UART_RF);
 787
 788                if (sr & UART_SR_RX_BREAK) {
 789                        port->icount.brk++;
 790                        if (uart_handle_break(port))
 791                                continue;
 792                } else if (sr & UART_SR_PAR_FRAME_ERR) {
 793                        port->icount.frame++;
 794                } else {
 795                        port->icount.rx++;
 796                }
 797
 798                /* Mask conditions we're ignorning. */
 799                sr &= port->read_status_mask;
 800
 801                if (sr & UART_SR_RX_BREAK)
 802                        flag = TTY_BREAK;
 803                else if (sr & UART_SR_PAR_FRAME_ERR)
 804                        flag = TTY_FRAME;
 805
 806                spin_unlock(&port->lock);
 807                sysrq = uart_handle_sysrq_char(port, c);
 808                spin_lock(&port->lock);
 809                if (!sysrq)
 810                        tty_insert_flip_char(tport, c, flag);
 811        }
 812
 813        spin_unlock(&port->lock);
 814        tty_flip_buffer_push(tport);
 815        spin_lock(&port->lock);
 816}
 817
 818static void msm_handle_tx_pio(struct uart_port *port, unsigned int tx_count)
 819{
 820        struct circ_buf *xmit = &port->state->xmit;
 821        struct msm_port *msm_port = UART_TO_MSM(port);
 822        unsigned int num_chars;
 823        unsigned int tf_pointer = 0;
 824        void __iomem *tf;
 825
 826        if (msm_port->is_uartdm)
 827                tf = port->membase + UARTDM_TF;
 828        else
 829                tf = port->membase + UART_TF;
 830
 831        if (tx_count && msm_port->is_uartdm)
 832                msm_reset_dm_count(port, tx_count);
 833
 834        while (tf_pointer < tx_count) {
 835                int i;
 836                char buf[4] = { 0 };
 837
 838                if (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
 839                        break;
 840
 841                if (msm_port->is_uartdm)
 842                        num_chars = min(tx_count - tf_pointer,
 843                                        (unsigned int)sizeof(buf));
 844                else
 845                        num_chars = 1;
 846
 847                for (i = 0; i < num_chars; i++) {
 848                        buf[i] = xmit->buf[xmit->tail + i];
 849                        port->icount.tx++;
 850                }
 851
 852                iowrite32_rep(tf, buf, 1);
 853                xmit->tail = (xmit->tail + num_chars) & (UART_XMIT_SIZE - 1);
 854                tf_pointer += num_chars;
 855        }
 856
 857        /* disable tx interrupts if nothing more to send */
 858        if (uart_circ_empty(xmit))
 859                msm_stop_tx(port);
 860
 861        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 862                uart_write_wakeup(port);
 863}
 864
 865static void msm_handle_tx(struct uart_port *port)
 866{
 867        struct msm_port *msm_port = UART_TO_MSM(port);
 868        struct circ_buf *xmit = &msm_port->uart.state->xmit;
 869        struct msm_dma *dma = &msm_port->tx_dma;
 870        unsigned int pio_count, dma_count, dma_min;
 871        void __iomem *tf;
 872        int err = 0;
 873
 874        if (port->x_char) {
 875                if (msm_port->is_uartdm)
 876                        tf = port->membase + UARTDM_TF;
 877                else
 878                        tf = port->membase + UART_TF;
 879
 880                if (msm_port->is_uartdm)
 881                        msm_reset_dm_count(port, 1);
 882
 883                iowrite8_rep(tf, &port->x_char, 1);
 884                port->icount.tx++;
 885                port->x_char = 0;
 886                return;
 887        }
 888
 889        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 890                msm_stop_tx(port);
 891                return;
 892        }
 893
 894        pio_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 895        dma_count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 896
 897        dma_min = 1;    /* Always DMA */
 898        if (msm_port->is_uartdm > UARTDM_1P3) {
 899                dma_count = UARTDM_TX_AIGN(dma_count);
 900                dma_min = UARTDM_BURST_SIZE;
 901        } else {
 902                if (dma_count > UARTDM_TX_MAX)
 903                        dma_count = UARTDM_TX_MAX;
 904        }
 905
 906        if (pio_count > port->fifosize)
 907                pio_count = port->fifosize;
 908
 909        if (!dma->chan || dma_count < dma_min)
 910                msm_handle_tx_pio(port, pio_count);
 911        else
 912                err = msm_handle_tx_dma(msm_port, dma_count);
 913
 914        if (err)        /* fall back to PIO mode */
 915                msm_handle_tx_pio(port, pio_count);
 916}
 917
 918static void msm_handle_delta_cts(struct uart_port *port)
 919{
 920        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 921        port->icount.cts++;
 922        wake_up_interruptible(&port->state->port.delta_msr_wait);
 923}
 924
 925static irqreturn_t msm_uart_irq(int irq, void *dev_id)
 926{
 927        struct uart_port *port = dev_id;
 928        struct msm_port *msm_port = UART_TO_MSM(port);
 929        struct msm_dma *dma = &msm_port->rx_dma;
 930        unsigned long flags;
 931        unsigned int misr;
 932        u32 val;
 933
 934        spin_lock_irqsave(&port->lock, flags);
 935        misr = msm_read(port, UART_MISR);
 936        msm_write(port, 0, UART_IMR); /* disable interrupt */
 937
 938        if (misr & UART_IMR_RXBREAK_START) {
 939                msm_port->break_detected = true;
 940                msm_write(port, UART_CR_CMD_RESET_RXBREAK_START, UART_CR);
 941        }
 942
 943        if (misr & (UART_IMR_RXLEV | UART_IMR_RXSTALE)) {
 944                if (dma->count) {
 945                        val = UART_CR_CMD_STALE_EVENT_DISABLE;
 946                        msm_write(port, val, UART_CR);
 947                        val = UART_CR_CMD_RESET_STALE_INT;
 948                        msm_write(port, val, UART_CR);
 949                        /*
 950                         * Flush DMA input fifo to memory, this will also
 951                         * trigger DMA RX completion
 952                         */
 953                        dmaengine_terminate_all(dma->chan);
 954                } else if (msm_port->is_uartdm) {
 955                        msm_handle_rx_dm(port, misr);
 956                } else {
 957                        msm_handle_rx(port);
 958                }
 959        }
 960        if (misr & UART_IMR_TXLEV)
 961                msm_handle_tx(port);
 962        if (misr & UART_IMR_DELTA_CTS)
 963                msm_handle_delta_cts(port);
 964
 965        msm_write(port, msm_port->imr, UART_IMR); /* restore interrupt */
 966        spin_unlock_irqrestore(&port->lock, flags);
 967
 968        return IRQ_HANDLED;
 969}
 970
 971static unsigned int msm_tx_empty(struct uart_port *port)
 972{
 973        return (msm_read(port, UART_SR) & UART_SR_TX_EMPTY) ? TIOCSER_TEMT : 0;
 974}
 975
 976static unsigned int msm_get_mctrl(struct uart_port *port)
 977{
 978        return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR | TIOCM_RTS;
 979}
 980
 981static void msm_reset(struct uart_port *port)
 982{
 983        struct msm_port *msm_port = UART_TO_MSM(port);
 984
 985        /* reset everything */
 986        msm_write(port, UART_CR_CMD_RESET_RX, UART_CR);
 987        msm_write(port, UART_CR_CMD_RESET_TX, UART_CR);
 988        msm_write(port, UART_CR_CMD_RESET_ERR, UART_CR);
 989        msm_write(port, UART_CR_CMD_RESET_BREAK_INT, UART_CR);
 990        msm_write(port, UART_CR_CMD_RESET_CTS, UART_CR);
 991        msm_write(port, UART_CR_CMD_SET_RFR, UART_CR);
 992
 993        /* Disable DM modes */
 994        if (msm_port->is_uartdm)
 995                msm_write(port, 0, UARTDM_DMEN);
 996}
 997
 998static void msm_set_mctrl(struct uart_port *port, unsigned int mctrl)
 999{
1000        unsigned int mr;
1001
1002        mr = msm_read(port, UART_MR1);
1003
1004        if (!(mctrl & TIOCM_RTS)) {
1005                mr &= ~UART_MR1_RX_RDY_CTL;
1006                msm_write(port, mr, UART_MR1);
1007                msm_write(port, UART_CR_CMD_RESET_RFR, UART_CR);
1008        } else {
1009                mr |= UART_MR1_RX_RDY_CTL;
1010                msm_write(port, mr, UART_MR1);
1011        }
1012}
1013
1014static void msm_break_ctl(struct uart_port *port, int break_ctl)
1015{
1016        if (break_ctl)
1017                msm_write(port, UART_CR_CMD_START_BREAK, UART_CR);
1018        else
1019                msm_write(port, UART_CR_CMD_STOP_BREAK, UART_CR);
1020}
1021
1022struct msm_baud_map {
1023        u16     divisor;
1024        u8      code;
1025        u8      rxstale;
1026};
1027
1028static const struct msm_baud_map *
1029msm_find_best_baud(struct uart_port *port, unsigned int baud,
1030                   unsigned long *rate)
1031{
1032        struct msm_port *msm_port = UART_TO_MSM(port);
1033        unsigned int divisor, result;
1034        unsigned long target, old, best_rate = 0, diff, best_diff = ULONG_MAX;
1035        const struct msm_baud_map *entry, *end, *best;
1036        static const struct msm_baud_map table[] = {
1037                {    1, 0xff, 31 },
1038                {    2, 0xee, 16 },
1039                {    3, 0xdd,  8 },
1040                {    4, 0xcc,  6 },
1041                {    6, 0xbb,  6 },
1042                {    8, 0xaa,  6 },
1043                {   12, 0x99,  6 },
1044                {   16, 0x88,  1 },
1045                {   24, 0x77,  1 },
1046                {   32, 0x66,  1 },
1047                {   48, 0x55,  1 },
1048                {   96, 0x44,  1 },
1049                {  192, 0x33,  1 },
1050                {  384, 0x22,  1 },
1051                {  768, 0x11,  1 },
1052                { 1536, 0x00,  1 },
1053        };
1054
1055        best = table; /* Default to smallest divider */
1056        target = clk_round_rate(msm_port->clk, 16 * baud);
1057        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1058
1059        end = table + ARRAY_SIZE(table);
1060        entry = table;
1061        while (entry < end) {
1062                if (entry->divisor <= divisor) {
1063                        result = target / entry->divisor / 16;
1064                        diff = abs(result - baud);
1065
1066                        /* Keep track of best entry */
1067                        if (diff < best_diff) {
1068                                best_diff = diff;
1069                                best = entry;
1070                                best_rate = target;
1071                        }
1072
1073                        if (result == baud)
1074                                break;
1075                } else if (entry->divisor > divisor) {
1076                        old = target;
1077                        target = clk_round_rate(msm_port->clk, old + 1);
1078                        /*
1079                         * The rate didn't get any faster so we can't do
1080                         * better at dividing it down
1081                         */
1082                        if (target == old)
1083                                break;
1084
1085                        /* Start the divisor search over at this new rate */
1086                        entry = table;
1087                        divisor = DIV_ROUND_CLOSEST(target, 16 * baud);
1088                        continue;
1089                }
1090                entry++;
1091        }
1092
1093        *rate = best_rate;
1094        return best;
1095}
1096
1097static int msm_set_baud_rate(struct uart_port *port, unsigned int baud,
1098                             unsigned long *saved_flags)
1099{
1100        unsigned int rxstale, watermark, mask;
1101        struct msm_port *msm_port = UART_TO_MSM(port);
1102        const struct msm_baud_map *entry;
1103        unsigned long flags, rate;
1104
1105        flags = *saved_flags;
1106        spin_unlock_irqrestore(&port->lock, flags);
1107
1108        entry = msm_find_best_baud(port, baud, &rate);
1109        clk_set_rate(msm_port->clk, rate);
1110        baud = rate / 16 / entry->divisor;
1111
1112        spin_lock_irqsave(&port->lock, flags);
1113        *saved_flags = flags;
1114        port->uartclk = rate;
1115
1116        msm_write(port, entry->code, UART_CSR);
1117
1118        /* RX stale watermark */
1119        rxstale = entry->rxstale;
1120        watermark = UART_IPR_STALE_LSB & rxstale;
1121        if (msm_port->is_uartdm) {
1122                mask = UART_DM_IPR_STALE_TIMEOUT_MSB;
1123        } else {
1124                watermark |= UART_IPR_RXSTALE_LAST;
1125                mask = UART_IPR_STALE_TIMEOUT_MSB;
1126        }
1127
1128        watermark |= mask & (rxstale << 2);
1129
1130        msm_write(port, watermark, UART_IPR);
1131
1132        /* set RX watermark */
1133        watermark = (port->fifosize * 3) / 4;
1134        msm_write(port, watermark, UART_RFWR);
1135
1136        /* set TX watermark */
1137        msm_write(port, 10, UART_TFWR);
1138
1139        msm_write(port, UART_CR_CMD_PROTECTION_EN, UART_CR);
1140        msm_reset(port);
1141
1142        /* Enable RX and TX */
1143        msm_write(port, UART_CR_TX_ENABLE | UART_CR_RX_ENABLE, UART_CR);
1144
1145        /* turn on RX and CTS interrupts */
1146        msm_port->imr = UART_IMR_RXLEV | UART_IMR_RXSTALE |
1147                        UART_IMR_CURRENT_CTS | UART_IMR_RXBREAK_START;
1148
1149        msm_write(port, msm_port->imr, UART_IMR);
1150
1151        if (msm_port->is_uartdm) {
1152                msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1153                msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1154                msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE, UART_CR);
1155        }
1156
1157        return baud;
1158}
1159
1160static void msm_init_clock(struct uart_port *port)
1161{
1162        struct msm_port *msm_port = UART_TO_MSM(port);
1163
1164        clk_prepare_enable(msm_port->clk);
1165        clk_prepare_enable(msm_port->pclk);
1166        msm_serial_set_mnd_regs(port);
1167}
1168
1169static int msm_startup(struct uart_port *port)
1170{
1171        struct msm_port *msm_port = UART_TO_MSM(port);
1172        unsigned int data, rfr_level, mask;
1173        int ret;
1174
1175        snprintf(msm_port->name, sizeof(msm_port->name),
1176                 "msm_serial%d", port->line);
1177
1178        ret = request_irq(port->irq, msm_uart_irq, IRQF_TRIGGER_HIGH,
1179                          msm_port->name, port);
1180        if (unlikely(ret))
1181                return ret;
1182
1183        msm_init_clock(port);
1184
1185        if (likely(port->fifosize > 12))
1186                rfr_level = port->fifosize - 12;
1187        else
1188                rfr_level = port->fifosize;
1189
1190        /* set automatic RFR level */
1191        data = msm_read(port, UART_MR1);
1192
1193        if (msm_port->is_uartdm)
1194                mask = UART_DM_MR1_AUTO_RFR_LEVEL1;
1195        else
1196                mask = UART_MR1_AUTO_RFR_LEVEL1;
1197
1198        data &= ~mask;
1199        data &= ~UART_MR1_AUTO_RFR_LEVEL0;
1200        data |= mask & (rfr_level << 2);
1201        data |= UART_MR1_AUTO_RFR_LEVEL0 & rfr_level;
1202        msm_write(port, data, UART_MR1);
1203
1204        if (msm_port->is_uartdm) {
1205                msm_request_tx_dma(msm_port, msm_port->uart.mapbase);
1206                msm_request_rx_dma(msm_port, msm_port->uart.mapbase);
1207        }
1208
1209        return 0;
1210}
1211
1212static void msm_shutdown(struct uart_port *port)
1213{
1214        struct msm_port *msm_port = UART_TO_MSM(port);
1215
1216        msm_port->imr = 0;
1217        msm_write(port, 0, UART_IMR); /* disable interrupts */
1218
1219        if (msm_port->is_uartdm)
1220                msm_release_dma(msm_port);
1221
1222        clk_disable_unprepare(msm_port->clk);
1223
1224        free_irq(port->irq, port);
1225}
1226
1227static void msm_set_termios(struct uart_port *port, struct ktermios *termios,
1228                            struct ktermios *old)
1229{
1230        struct msm_port *msm_port = UART_TO_MSM(port);
1231        struct msm_dma *dma = &msm_port->rx_dma;
1232        unsigned long flags;
1233        unsigned int baud, mr;
1234
1235        spin_lock_irqsave(&port->lock, flags);
1236
1237        if (dma->chan) /* Terminate if any */
1238                msm_stop_dma(port, dma);
1239
1240        /* calculate and set baud rate */
1241        baud = uart_get_baud_rate(port, termios, old, 300, 4000000);
1242        baud = msm_set_baud_rate(port, baud, &flags);
1243        if (tty_termios_baud_rate(termios))
1244                tty_termios_encode_baud_rate(termios, baud, baud);
1245
1246        /* calculate parity */
1247        mr = msm_read(port, UART_MR2);
1248        mr &= ~UART_MR2_PARITY_MODE;
1249        if (termios->c_cflag & PARENB) {
1250                if (termios->c_cflag & PARODD)
1251                        mr |= UART_MR2_PARITY_MODE_ODD;
1252                else if (termios->c_cflag & CMSPAR)
1253                        mr |= UART_MR2_PARITY_MODE_SPACE;
1254                else
1255                        mr |= UART_MR2_PARITY_MODE_EVEN;
1256        }
1257
1258        /* calculate bits per char */
1259        mr &= ~UART_MR2_BITS_PER_CHAR;
1260        switch (termios->c_cflag & CSIZE) {
1261        case CS5:
1262                mr |= UART_MR2_BITS_PER_CHAR_5;
1263                break;
1264        case CS6:
1265                mr |= UART_MR2_BITS_PER_CHAR_6;
1266                break;
1267        case CS7:
1268                mr |= UART_MR2_BITS_PER_CHAR_7;
1269                break;
1270        case CS8:
1271        default:
1272                mr |= UART_MR2_BITS_PER_CHAR_8;
1273                break;
1274        }
1275
1276        /* calculate stop bits */
1277        mr &= ~(UART_MR2_STOP_BIT_LEN_ONE | UART_MR2_STOP_BIT_LEN_TWO);
1278        if (termios->c_cflag & CSTOPB)
1279                mr |= UART_MR2_STOP_BIT_LEN_TWO;
1280        else
1281                mr |= UART_MR2_STOP_BIT_LEN_ONE;
1282
1283        /* set parity, bits per char, and stop bit */
1284        msm_write(port, mr, UART_MR2);
1285
1286        /* calculate and set hardware flow control */
1287        mr = msm_read(port, UART_MR1);
1288        mr &= ~(UART_MR1_CTS_CTL | UART_MR1_RX_RDY_CTL);
1289        if (termios->c_cflag & CRTSCTS) {
1290                mr |= UART_MR1_CTS_CTL;
1291                mr |= UART_MR1_RX_RDY_CTL;
1292        }
1293        msm_write(port, mr, UART_MR1);
1294
1295        /* Configure status bits to ignore based on termio flags. */
1296        port->read_status_mask = 0;
1297        if (termios->c_iflag & INPCK)
1298                port->read_status_mask |= UART_SR_PAR_FRAME_ERR;
1299        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1300                port->read_status_mask |= UART_SR_RX_BREAK;
1301
1302        uart_update_timeout(port, termios->c_cflag, baud);
1303
1304        /* Try to use DMA */
1305        msm_start_rx_dma(msm_port);
1306
1307        spin_unlock_irqrestore(&port->lock, flags);
1308}
1309
1310static const char *msm_type(struct uart_port *port)
1311{
1312        return "MSM";
1313}
1314
1315static void msm_release_port(struct uart_port *port)
1316{
1317        struct platform_device *pdev = to_platform_device(port->dev);
1318        struct resource *uart_resource;
1319        resource_size_t size;
1320
1321        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1322        if (unlikely(!uart_resource))
1323                return;
1324        size = resource_size(uart_resource);
1325
1326        release_mem_region(port->mapbase, size);
1327        iounmap(port->membase);
1328        port->membase = NULL;
1329}
1330
1331static int msm_request_port(struct uart_port *port)
1332{
1333        struct platform_device *pdev = to_platform_device(port->dev);
1334        struct resource *uart_resource;
1335        resource_size_t size;
1336        int ret;
1337
1338        uart_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1339        if (unlikely(!uart_resource))
1340                return -ENXIO;
1341
1342        size = resource_size(uart_resource);
1343
1344        if (!request_mem_region(port->mapbase, size, "msm_serial"))
1345                return -EBUSY;
1346
1347        port->membase = ioremap(port->mapbase, size);
1348        if (!port->membase) {
1349                ret = -EBUSY;
1350                goto fail_release_port;
1351        }
1352
1353        return 0;
1354
1355fail_release_port:
1356        release_mem_region(port->mapbase, size);
1357        return ret;
1358}
1359
1360static void msm_config_port(struct uart_port *port, int flags)
1361{
1362        int ret;
1363
1364        if (flags & UART_CONFIG_TYPE) {
1365                port->type = PORT_MSM;
1366                ret = msm_request_port(port);
1367                if (ret)
1368                        return;
1369        }
1370}
1371
1372static int msm_verify_port(struct uart_port *port, struct serial_struct *ser)
1373{
1374        if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_MSM))
1375                return -EINVAL;
1376        if (unlikely(port->irq != ser->irq))
1377                return -EINVAL;
1378        return 0;
1379}
1380
1381static void msm_power(struct uart_port *port, unsigned int state,
1382                      unsigned int oldstate)
1383{
1384        struct msm_port *msm_port = UART_TO_MSM(port);
1385
1386        switch (state) {
1387        case 0:
1388                clk_prepare_enable(msm_port->clk);
1389                clk_prepare_enable(msm_port->pclk);
1390                break;
1391        case 3:
1392                clk_disable_unprepare(msm_port->clk);
1393                clk_disable_unprepare(msm_port->pclk);
1394                break;
1395        default:
1396                pr_err("msm_serial: Unknown PM state %d\n", state);
1397        }
1398}
1399
1400#ifdef CONFIG_CONSOLE_POLL
1401static int msm_poll_get_char_single(struct uart_port *port)
1402{
1403        struct msm_port *msm_port = UART_TO_MSM(port);
1404        unsigned int rf_reg = msm_port->is_uartdm ? UARTDM_RF : UART_RF;
1405
1406        if (!(msm_read(port, UART_SR) & UART_SR_RX_READY))
1407                return NO_POLL_CHAR;
1408
1409        return msm_read(port, rf_reg) & 0xff;
1410}
1411
1412static int msm_poll_get_char_dm(struct uart_port *port)
1413{
1414        int c;
1415        static u32 slop;
1416        static int count;
1417        unsigned char *sp = (unsigned char *)&slop;
1418
1419        /* Check if a previous read had more than one char */
1420        if (count) {
1421                c = sp[sizeof(slop) - count];
1422                count--;
1423        /* Or if FIFO is empty */
1424        } else if (!(msm_read(port, UART_SR) & UART_SR_RX_READY)) {
1425                /*
1426                 * If RX packing buffer has less than a word, force stale to
1427                 * push contents into RX FIFO
1428                 */
1429                count = msm_read(port, UARTDM_RXFS);
1430                count = (count >> UARTDM_RXFS_BUF_SHIFT) & UARTDM_RXFS_BUF_MASK;
1431                if (count) {
1432                        msm_write(port, UART_CR_CMD_FORCE_STALE, UART_CR);
1433                        slop = msm_read(port, UARTDM_RF);
1434                        c = sp[0];
1435                        count--;
1436                        msm_write(port, UART_CR_CMD_RESET_STALE_INT, UART_CR);
1437                        msm_write(port, 0xFFFFFF, UARTDM_DMRX);
1438                        msm_write(port, UART_CR_CMD_STALE_EVENT_ENABLE,
1439                                  UART_CR);
1440                } else {
1441                        c = NO_POLL_CHAR;
1442                }
1443        /* FIFO has a word */
1444        } else {
1445                slop = msm_read(port, UARTDM_RF);
1446                c = sp[0];
1447                count = sizeof(slop) - 1;
1448        }
1449
1450        return c;
1451}
1452
1453static int msm_poll_get_char(struct uart_port *port)
1454{
1455        u32 imr;
1456        int c;
1457        struct msm_port *msm_port = UART_TO_MSM(port);
1458
1459        /* Disable all interrupts */
1460        imr = msm_read(port, UART_IMR);
1461        msm_write(port, 0, UART_IMR);
1462
1463        if (msm_port->is_uartdm)
1464                c = msm_poll_get_char_dm(port);
1465        else
1466                c = msm_poll_get_char_single(port);
1467
1468        /* Enable interrupts */
1469        msm_write(port, imr, UART_IMR);
1470
1471        return c;
1472}
1473
1474static void msm_poll_put_char(struct uart_port *port, unsigned char c)
1475{
1476        u32 imr;
1477        struct msm_port *msm_port = UART_TO_MSM(port);
1478
1479        /* Disable all interrupts */
1480        imr = msm_read(port, UART_IMR);
1481        msm_write(port, 0, UART_IMR);
1482
1483        if (msm_port->is_uartdm)
1484                msm_reset_dm_count(port, 1);
1485
1486        /* Wait until FIFO is empty */
1487        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1488                cpu_relax();
1489
1490        /* Write a character */
1491        msm_write(port, c, msm_port->is_uartdm ? UARTDM_TF : UART_TF);
1492
1493        /* Wait until FIFO is empty */
1494        while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1495                cpu_relax();
1496
1497        /* Enable interrupts */
1498        msm_write(port, imr, UART_IMR);
1499}
1500#endif
1501
1502static struct uart_ops msm_uart_pops = {
1503        .tx_empty = msm_tx_empty,
1504        .set_mctrl = msm_set_mctrl,
1505        .get_mctrl = msm_get_mctrl,
1506        .stop_tx = msm_stop_tx,
1507        .start_tx = msm_start_tx,
1508        .stop_rx = msm_stop_rx,
1509        .enable_ms = msm_enable_ms,
1510        .break_ctl = msm_break_ctl,
1511        .startup = msm_startup,
1512        .shutdown = msm_shutdown,
1513        .set_termios = msm_set_termios,
1514        .type = msm_type,
1515        .release_port = msm_release_port,
1516        .request_port = msm_request_port,
1517        .config_port = msm_config_port,
1518        .verify_port = msm_verify_port,
1519        .pm = msm_power,
1520#ifdef CONFIG_CONSOLE_POLL
1521        .poll_get_char  = msm_poll_get_char,
1522        .poll_put_char  = msm_poll_put_char,
1523#endif
1524};
1525
1526static struct msm_port msm_uart_ports[] = {
1527        {
1528                .uart = {
1529                        .iotype = UPIO_MEM,
1530                        .ops = &msm_uart_pops,
1531                        .flags = UPF_BOOT_AUTOCONF,
1532                        .fifosize = 64,
1533                        .line = 0,
1534                },
1535        },
1536        {
1537                .uart = {
1538                        .iotype = UPIO_MEM,
1539                        .ops = &msm_uart_pops,
1540                        .flags = UPF_BOOT_AUTOCONF,
1541                        .fifosize = 64,
1542                        .line = 1,
1543                },
1544        },
1545        {
1546                .uart = {
1547                        .iotype = UPIO_MEM,
1548                        .ops = &msm_uart_pops,
1549                        .flags = UPF_BOOT_AUTOCONF,
1550                        .fifosize = 64,
1551                        .line = 2,
1552                },
1553        },
1554};
1555
1556#define UART_NR ARRAY_SIZE(msm_uart_ports)
1557
1558static inline struct uart_port *msm_get_port_from_line(unsigned int line)
1559{
1560        return &msm_uart_ports[line].uart;
1561}
1562
1563#ifdef CONFIG_SERIAL_MSM_CONSOLE
1564static void __msm_console_write(struct uart_port *port, const char *s,
1565                                unsigned int count, bool is_uartdm)
1566{
1567        int i;
1568        int num_newlines = 0;
1569        bool replaced = false;
1570        void __iomem *tf;
1571
1572        if (is_uartdm)
1573                tf = port->membase + UARTDM_TF;
1574        else
1575                tf = port->membase + UART_TF;
1576
1577        /* Account for newlines that will get a carriage return added */
1578        for (i = 0; i < count; i++)
1579                if (s[i] == '\n')
1580                        num_newlines++;
1581        count += num_newlines;
1582
1583        spin_lock(&port->lock);
1584        if (is_uartdm)
1585                msm_reset_dm_count(port, count);
1586
1587        i = 0;
1588        while (i < count) {
1589                int j;
1590                unsigned int num_chars;
1591                char buf[4] = { 0 };
1592
1593                if (is_uartdm)
1594                        num_chars = min(count - i, (unsigned int)sizeof(buf));
1595                else
1596                        num_chars = 1;
1597
1598                for (j = 0; j < num_chars; j++) {
1599                        char c = *s;
1600
1601                        if (c == '\n' && !replaced) {
1602                                buf[j] = '\r';
1603                                j++;
1604                                replaced = true;
1605                        }
1606                        if (j < num_chars) {
1607                                buf[j] = c;
1608                                s++;
1609                                replaced = false;
1610                        }
1611                }
1612
1613                while (!(msm_read(port, UART_SR) & UART_SR_TX_READY))
1614                        cpu_relax();
1615
1616                iowrite32_rep(tf, buf, 1);
1617                i += num_chars;
1618        }
1619        spin_unlock(&port->lock);
1620}
1621
1622static void msm_console_write(struct console *co, const char *s,
1623                              unsigned int count)
1624{
1625        struct uart_port *port;
1626        struct msm_port *msm_port;
1627
1628        BUG_ON(co->index < 0 || co->index >= UART_NR);
1629
1630        port = msm_get_port_from_line(co->index);
1631        msm_port = UART_TO_MSM(port);
1632
1633        __msm_console_write(port, s, count, msm_port->is_uartdm);
1634}
1635
1636static int __init msm_console_setup(struct console *co, char *options)
1637{
1638        struct uart_port *port;
1639        int baud = 115200;
1640        int bits = 8;
1641        int parity = 'n';
1642        int flow = 'n';
1643
1644        if (unlikely(co->index >= UART_NR || co->index < 0))
1645                return -ENXIO;
1646
1647        port = msm_get_port_from_line(co->index);
1648
1649        if (unlikely(!port->membase))
1650                return -ENXIO;
1651
1652        msm_init_clock(port);
1653
1654        if (options)
1655                uart_parse_options(options, &baud, &parity, &bits, &flow);
1656
1657        pr_info("msm_serial: console setup on port #%d\n", port->line);
1658
1659        return uart_set_options(port, co, baud, parity, bits, flow);
1660}
1661
1662static void
1663msm_serial_early_write(struct console *con, const char *s, unsigned n)
1664{
1665        struct earlycon_device *dev = con->data;
1666
1667        __msm_console_write(&dev->port, s, n, false);
1668}
1669
1670static int __init
1671msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
1672{
1673        if (!device->port.membase)
1674                return -ENODEV;
1675
1676        device->con->write = msm_serial_early_write;
1677        return 0;
1678}
1679OF_EARLYCON_DECLARE(msm_serial, "qcom,msm-uart",
1680                    msm_serial_early_console_setup);
1681
1682static void
1683msm_serial_early_write_dm(struct console *con, const char *s, unsigned n)
1684{
1685        struct earlycon_device *dev = con->data;
1686
1687        __msm_console_write(&dev->port, s, n, true);
1688}
1689
1690static int __init
1691msm_serial_early_console_setup_dm(struct earlycon_device *device,
1692                                  const char *opt)
1693{
1694        if (!device->port.membase)
1695                return -ENODEV;
1696
1697        device->con->write = msm_serial_early_write_dm;
1698        return 0;
1699}
1700OF_EARLYCON_DECLARE(msm_serial_dm, "qcom,msm-uartdm",
1701                    msm_serial_early_console_setup_dm);
1702
1703static struct uart_driver msm_uart_driver;
1704
1705static struct console msm_console = {
1706        .name = "ttyMSM",
1707        .write = msm_console_write,
1708        .device = uart_console_device,
1709        .setup = msm_console_setup,
1710        .flags = CON_PRINTBUFFER,
1711        .index = -1,
1712        .data = &msm_uart_driver,
1713};
1714
1715#define MSM_CONSOLE     (&msm_console)
1716
1717#else
1718#define MSM_CONSOLE     NULL
1719#endif
1720
1721static struct uart_driver msm_uart_driver = {
1722        .owner = THIS_MODULE,
1723        .driver_name = "msm_serial",
1724        .dev_name = "ttyMSM",
1725        .nr = UART_NR,
1726        .cons = MSM_CONSOLE,
1727};
1728
1729static atomic_t msm_uart_next_id = ATOMIC_INIT(0);
1730
1731static const struct of_device_id msm_uartdm_table[] = {
1732        { .compatible = "qcom,msm-uartdm-v1.1", .data = (void *)UARTDM_1P1 },
1733        { .compatible = "qcom,msm-uartdm-v1.2", .data = (void *)UARTDM_1P2 },
1734        { .compatible = "qcom,msm-uartdm-v1.3", .data = (void *)UARTDM_1P3 },
1735        { .compatible = "qcom,msm-uartdm-v1.4", .data = (void *)UARTDM_1P4 },
1736        { }
1737};
1738
1739static int msm_serial_probe(struct platform_device *pdev)
1740{
1741        struct msm_port *msm_port;
1742        struct resource *resource;
1743        struct uart_port *port;
1744        const struct of_device_id *id;
1745        int irq, line;
1746
1747        if (pdev->dev.of_node)
1748                line = of_alias_get_id(pdev->dev.of_node, "serial");
1749        else
1750                line = pdev->id;
1751
1752        if (line < 0)
1753                line = atomic_inc_return(&msm_uart_next_id) - 1;
1754
1755        if (unlikely(line < 0 || line >= UART_NR))
1756                return -ENXIO;
1757
1758        dev_info(&pdev->dev, "msm_serial: detected port #%d\n", line);
1759
1760        port = msm_get_port_from_line(line);
1761        port->dev = &pdev->dev;
1762        msm_port = UART_TO_MSM(port);
1763
1764        id = of_match_device(msm_uartdm_table, &pdev->dev);
1765        if (id)
1766                msm_port->is_uartdm = (unsigned long)id->data;
1767        else
1768                msm_port->is_uartdm = 0;
1769
1770        msm_port->clk = devm_clk_get(&pdev->dev, "core");
1771        if (IS_ERR(msm_port->clk))
1772                return PTR_ERR(msm_port->clk);
1773
1774        if (msm_port->is_uartdm) {
1775                msm_port->pclk = devm_clk_get(&pdev->dev, "iface");
1776                if (IS_ERR(msm_port->pclk))
1777                        return PTR_ERR(msm_port->pclk);
1778        }
1779
1780        port->uartclk = clk_get_rate(msm_port->clk);
1781        dev_info(&pdev->dev, "uartclk = %d\n", port->uartclk);
1782
1783        resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1784        if (unlikely(!resource))
1785                return -ENXIO;
1786        port->mapbase = resource->start;
1787
1788        irq = platform_get_irq(pdev, 0);
1789        if (unlikely(irq < 0))
1790                return -ENXIO;
1791        port->irq = irq;
1792
1793        platform_set_drvdata(pdev, port);
1794
1795        return uart_add_one_port(&msm_uart_driver, port);
1796}
1797
1798static int msm_serial_remove(struct platform_device *pdev)
1799{
1800        struct uart_port *port = platform_get_drvdata(pdev);
1801
1802        uart_remove_one_port(&msm_uart_driver, port);
1803
1804        return 0;
1805}
1806
1807static const struct of_device_id msm_match_table[] = {
1808        { .compatible = "qcom,msm-uart" },
1809        { .compatible = "qcom,msm-uartdm" },
1810        {}
1811};
1812MODULE_DEVICE_TABLE(of, msm_match_table);
1813
1814static struct platform_driver msm_platform_driver = {
1815        .remove = msm_serial_remove,
1816        .probe = msm_serial_probe,
1817        .driver = {
1818                .name = "msm_serial",
1819                .of_match_table = msm_match_table,
1820        },
1821};
1822
1823static int __init msm_serial_init(void)
1824{
1825        int ret;
1826
1827        ret = uart_register_driver(&msm_uart_driver);
1828        if (unlikely(ret))
1829                return ret;
1830
1831        ret = platform_driver_register(&msm_platform_driver);
1832        if (unlikely(ret))
1833                uart_unregister_driver(&msm_uart_driver);
1834
1835        pr_info("msm_serial: driver initialized\n");
1836
1837        return ret;
1838}
1839
1840static void __exit msm_serial_exit(void)
1841{
1842        platform_driver_unregister(&msm_platform_driver);
1843        uart_unregister_driver(&msm_uart_driver);
1844}
1845
1846module_init(msm_serial_init);
1847module_exit(msm_serial_exit);
1848
1849MODULE_AUTHOR("Robert Love <rlove@google.com>");
1850MODULE_DESCRIPTION("Driver for msm7x serial device");
1851MODULE_LICENSE("GPL");
1852