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/* linux/drivers/spi/spi_s3c64xx.c
*
* Copyright (C) 2009 Samsung Electronics Ltd.
* Jaswinder Singh <jassi.brar@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <linux/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>

#include <mach/dma.h>
#include <plat/s3c64xx-spi.h>

/* Registers and bit-fields */

#define S3C64XX_SPI_CH_CFG 0x00
#define S3C64XX_SPI_CLK_CFG 0x04
#define S3C64XX_SPI_MODE_CFG 0x08
#define S3C64XX_SPI_SLAVE_SEL 0x0C
#define S3C64XX_SPI_INT_EN 0x10
#define S3C64XX_SPI_STATUS 0x14
#define S3C64XX_SPI_TX_DATA 0x18
#define S3C64XX_SPI_RX_DATA 0x1C
#define S3C64XX_SPI_PACKET_CNT 0x20
#define S3C64XX_SPI_PENDING_CLR 0x24
#define S3C64XX_SPI_SWAP_CFG 0x28
#define S3C64XX_SPI_FB_CLK 0x2C

#define S3C64XX_SPI_CH_HS_EN (1<<6) /* High Speed Enable */
#define S3C64XX_SPI_CH_SW_RST (1<<5)
#define S3C64XX_SPI_CH_SLAVE (1<<4)
#define S3C64XX_SPI_CPOL_L (1<<3)
#define S3C64XX_SPI_CPHA_B (1<<2)
#define S3C64XX_SPI_CH_RXCH_ON (1<<1)
#define S3C64XX_SPI_CH_TXCH_ON (1<<0)

#define S3C64XX_SPI_CLKSEL_SRCMSK (3<<9)
#define S3C64XX_SPI_CLKSEL_SRCSHFT 9
#define S3C64XX_SPI_ENCLK_ENABLE (1<<8)
#define S3C64XX_SPI_PSR_MASK 0xff

#define S3C64XX_SPI_MODE_CH_TSZ_BYTE (0<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_HALFWORD (1<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_WORD (2<<29)
#define S3C64XX_SPI_MODE_CH_TSZ_MASK (3<<29)
#define S3C64XX_SPI_MODE_BUS_TSZ_BYTE (0<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD (1<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_WORD (2<<17)
#define S3C64XX_SPI_MODE_BUS_TSZ_MASK (3<<17)
#define S3C64XX_SPI_MODE_RXDMA_ON (1<<2)
#define S3C64XX_SPI_MODE_TXDMA_ON (1<<1)
#define S3C64XX_SPI_MODE_4BURST (1<<0)

#define S3C64XX_SPI_SLAVE_AUTO (1<<1)
#define S3C64XX_SPI_SLAVE_SIG_INACT (1<<0)

#define S3C64XX_SPI_ACT(c) writel(0, (c)->regs + S3C64XX_SPI_SLAVE_SEL)

#define S3C64XX_SPI_DEACT(c) writel(S3C64XX_SPI_SLAVE_SIG_INACT, \
(c)->regs + S3C64XX_SPI_SLAVE_SEL)

#define S3C64XX_SPI_INT_TRAILING_EN (1<<6)
#define S3C64XX_SPI_INT_RX_OVERRUN_EN (1<<5)
#define S3C64XX_SPI_INT_RX_UNDERRUN_EN (1<<4)
#define S3C64XX_SPI_INT_TX_OVERRUN_EN (1<<3)
#define S3C64XX_SPI_INT_TX_UNDERRUN_EN (1<<2)
#define S3C64XX_SPI_INT_RX_FIFORDY_EN (1<<1)
#define S3C64XX_SPI_INT_TX_FIFORDY_EN (1<<0)

#define S3C64XX_SPI_ST_RX_OVERRUN_ERR (1<<5)
#define S3C64XX_SPI_ST_RX_UNDERRUN_ERR (1<<4)
#define S3C64XX_SPI_ST_TX_OVERRUN_ERR (1<<3)
#define S3C64XX_SPI_ST_TX_UNDERRUN_ERR (1<<2)
#define S3C64XX_SPI_ST_RX_FIFORDY (1<<1)
#define S3C64XX_SPI_ST_TX_FIFORDY (1<<0)

#define S3C64XX_SPI_PACKET_CNT_EN (1<<16)

#define S3C64XX_SPI_PND_TX_UNDERRUN_CLR (1<<4)
#define S3C64XX_SPI_PND_TX_OVERRUN_CLR (1<<3)
#define S3C64XX_SPI_PND_RX_UNDERRUN_CLR (1<<2)
#define S3C64XX_SPI_PND_RX_OVERRUN_CLR (1<<1)
#define S3C64XX_SPI_PND_TRAILING_CLR (1<<0)

#define S3C64XX_SPI_SWAP_RX_HALF_WORD (1<<7)
#define S3C64XX_SPI_SWAP_RX_BYTE (1<<6)
#define S3C64XX_SPI_SWAP_RX_BIT (1<<5)
#define S3C64XX_SPI_SWAP_RX_EN (1<<4)
#define S3C64XX_SPI_SWAP_TX_HALF_WORD (1<<3)
#define S3C64XX_SPI_SWAP_TX_BYTE (1<<2)
#define S3C64XX_SPI_SWAP_TX_BIT (1<<1)
#define S3C64XX_SPI_SWAP_TX_EN (1<<0)

#define S3C64XX_SPI_FBCLK_MSK (3<<0)

#define S3C64XX_SPI_ST_TRLCNTZ(v, i) ((((v) >> (i)->rx_lvl_offset) & \
(((i)->fifo_lvl_mask + 1))) \
? 1 : 0)

#define S3C64XX_SPI_ST_TX_DONE(v, i) (((v) & (1 << (i)->tx_st_done)) ? 1 : 0)
#define TX_FIFO_LVL(v, i) (((v) >> 6) & (i)->fifo_lvl_mask)
#define RX_FIFO_LVL(v, i) (((v) >> (i)->rx_lvl_offset) & (i)->fifo_lvl_mask)

#define S3C64XX_SPI_MAX_TRAILCNT 0x3ff
#define S3C64XX_SPI_TRAILCNT_OFF 19

#define S3C64XX_SPI_TRAILCNT S3C64XX_SPI_MAX_TRAILCNT

#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)

#define SUSPND (1<<0)
#define SPIBUSY (1<<1)
#define RXBUSY (1<<2)
#define TXBUSY (1<<3)

/**
* struct s3c64xx_spi_driver_data - Runtime info holder for SPI driver.
* @clk: Pointer to the spi clock.
* @src_clk: Pointer to the clock used to generate SPI signals.
* @master: Pointer to the SPI Protocol master.
* @workqueue: Work queue for the SPI xfer requests.
* @cntrlr_info: Platform specific data for the controller this driver manages.
* @tgl_spi: Pointer to the last CS left untoggled by the cs_change hint.
* @work: Work
* @queue: To log SPI xfer requests.
* @lock: Controller specific lock.
* @state: Set of FLAGS to indicate status.
* @rx_dmach: Controller's DMA channel for Rx.
* @tx_dmach: Controller's DMA channel for Tx.
* @sfr_start: BUS address of SPI controller regs.
* @regs: Pointer to ioremap'ed controller registers.
* @xfer_completion: To indicate completion of xfer task.
* @cur_mode: Stores the active configuration of the controller.
* @cur_bpw: Stores the active bits per word settings.
* @cur_speed: Stores the active xfer clock speed.
*/
struct s3c64xx_spi_driver_data {
void __iomem *regs;
struct clk *clk;
struct clk *src_clk;
struct platform_device *pdev;
struct spi_master *master;
struct workqueue_struct *workqueue;
struct s3c64xx_spi_info *cntrlr_info;
struct spi_device *tgl_spi;
struct work_struct work;
struct list_head queue;
spinlock_t lock;
enum dma_ch rx_dmach;
enum dma_ch tx_dmach;
unsigned long sfr_start;
struct completion xfer_completion;
unsigned state;
unsigned cur_mode, cur_bpw;
unsigned cur_speed;
};

static struct s3c2410_dma_client s3c64xx_spi_dma_client = {
.name = "samsung-spi-dma",
};

static void flush_fifo(struct s3c64xx_spi_driver_data *sdd)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
void __iomem *regs = sdd->regs;
unsigned long loops;
u32 val;

writel(0, regs + S3C64XX_SPI_PACKET_CNT);

val = readl(regs + S3C64XX_SPI_CH_CFG);
val |= S3C64XX_SPI_CH_SW_RST;
val &= ~S3C64XX_SPI_CH_HS_EN;
writel(val, regs + S3C64XX_SPI_CH_CFG);

/* Flush TxFIFO*/
loops = msecs_to_loops(1);
do {
val = readl(regs + S3C64XX_SPI_STATUS);
} while (TX_FIFO_LVL(val, sci) && loops--);

if (loops == 0)
dev_warn(&sdd->pdev->dev, "Timed out flushing TX FIFO\n");

/* Flush RxFIFO*/
loops = msecs_to_loops(1);
do {
val = readl(regs + S3C64XX_SPI_STATUS);
if (RX_FIFO_LVL(val, sci))
readl(regs + S3C64XX_SPI_RX_DATA);
else
break;
} while (loops--);

if (loops == 0)
dev_warn(&sdd->pdev->dev, "Timed out flushing RX FIFO\n");

val = readl(regs + S3C64XX_SPI_CH_CFG);
val &= ~S3C64XX_SPI_CH_SW_RST;
writel(val, regs + S3C64XX_SPI_CH_CFG);

val = readl(regs + S3C64XX_SPI_MODE_CFG);
val &= ~(S3C64XX_SPI_MODE_TXDMA_ON | S3C64XX_SPI_MODE_RXDMA_ON);
writel(val, regs + S3C64XX_SPI_MODE_CFG);

val = readl(regs + S3C64XX_SPI_CH_CFG);
val &= ~(S3C64XX_SPI_CH_RXCH_ON | S3C64XX_SPI_CH_TXCH_ON);
writel(val, regs + S3C64XX_SPI_CH_CFG);
}

static void enable_datapath(struct s3c64xx_spi_driver_data *sdd,
struct spi_device *spi,
struct spi_transfer *xfer, int dma_mode)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
void __iomem *regs = sdd->regs;
u32 modecfg, chcfg;

modecfg = readl(regs + S3C64XX_SPI_MODE_CFG);
modecfg &= ~(S3C64XX_SPI_MODE_TXDMA_ON | S3C64XX_SPI_MODE_RXDMA_ON);

chcfg = readl(regs + S3C64XX_SPI_CH_CFG);
chcfg &= ~S3C64XX_SPI_CH_TXCH_ON;

if (dma_mode) {
chcfg &= ~S3C64XX_SPI_CH_RXCH_ON;
} else {
/* Always shift in data in FIFO, even if xfer is Tx only,
* this helps setting PCKT_CNT value for generating clocks
* as exactly needed.
*/
chcfg |= S3C64XX_SPI_CH_RXCH_ON;
writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
| S3C64XX_SPI_PACKET_CNT_EN,
regs + S3C64XX_SPI_PACKET_CNT);
}

if (xfer->tx_buf != NULL) {
sdd->state |= TXBUSY;
chcfg |= S3C64XX_SPI_CH_TXCH_ON;
if (dma_mode) {
modecfg |= S3C64XX_SPI_MODE_TXDMA_ON;
s3c2410_dma_config(sdd->tx_dmach, sdd->cur_bpw / 8);
s3c2410_dma_enqueue(sdd->tx_dmach, (void *)sdd,
xfer->tx_dma, xfer->len);
s3c2410_dma_ctrl(sdd->tx_dmach, S3C2410_DMAOP_START);
} else {
switch (sdd->cur_bpw) {
case 32:
iowrite32_rep(regs + S3C64XX_SPI_TX_DATA,
xfer->tx_buf, xfer->len / 4);
break;
case 16:
iowrite16_rep(regs + S3C64XX_SPI_TX_DATA,
xfer->tx_buf, xfer->len / 2);
break;
default:
iowrite8_rep(regs + S3C64XX_SPI_TX_DATA,
xfer->tx_buf, xfer->len);
break;
}
}
}

if (xfer->rx_buf != NULL) {
sdd->state |= RXBUSY;

if (sci->high_speed && sdd->cur_speed >= 30000000UL
&& !(sdd->cur_mode & SPI_CPHA))
chcfg |= S3C64XX_SPI_CH_HS_EN;

if (dma_mode) {
modecfg |= S3C64XX_SPI_MODE_RXDMA_ON;
chcfg |= S3C64XX_SPI_CH_RXCH_ON;
writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
| S3C64XX_SPI_PACKET_CNT_EN,
regs + S3C64XX_SPI_PACKET_CNT);
s3c2410_dma_config(sdd->rx_dmach, sdd->cur_bpw / 8);
s3c2410_dma_enqueue(sdd->rx_dmach, (void *)sdd,
xfer->rx_dma, xfer->len);
s3c2410_dma_ctrl(sdd->rx_dmach, S3C2410_DMAOP_START);
}
}

writel(modecfg, regs + S3C64XX_SPI_MODE_CFG);
writel(chcfg, regs + S3C64XX_SPI_CH_CFG);
}

static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd,
struct spi_device *spi)
{
struct s3c64xx_spi_csinfo *cs;

if (sdd->tgl_spi != NULL) { /* If last device toggled after mssg */
if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
/* Deselect the last toggled device */
cs = sdd->tgl_spi->controller_data;
cs->set_level(cs->line,
spi->mode & SPI_CS_HIGH ? 0 : 1);
}
sdd->tgl_spi = NULL;
}

cs = spi->controller_data;
cs->set_level(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0);
}

static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd,
struct spi_transfer *xfer, int dma_mode)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
void __iomem *regs = sdd->regs;
unsigned long val;
int ms;

/* millisecs to xfer 'len' bytes @ 'cur_speed' */
ms = xfer->len * 8 * 1000 / sdd->cur_speed;
ms += 10; /* some tolerance */

if (dma_mode) {
val = msecs_to_jiffies(ms) + 10;
val = wait_for_completion_timeout(&sdd->xfer_completion, val);
} else {
u32 status;
val = msecs_to_loops(ms);
do {
status = readl(regs + S3C64XX_SPI_STATUS);
} while (RX_FIFO_LVL(status, sci) < xfer->len && --val);
}

if (!val)
return -EIO;

if (dma_mode) {
u32 status;

/*
* DmaTx returns after simply writing data in the FIFO,
* w/o waiting for real transmission on the bus to finish.
* DmaRx returns only after Dma read data from FIFO which
* needs bus transmission to finish, so we don't worry if
* Xfer involved Rx(with or without Tx).
*/
if (xfer->rx_buf == NULL) {
val = msecs_to_loops(10);
status = readl(regs + S3C64XX_SPI_STATUS);
while ((TX_FIFO_LVL(status, sci)
|| !S3C64XX_SPI_ST_TX_DONE(status, sci))
&& --val) {
cpu_relax();
status = readl(regs + S3C64XX_SPI_STATUS);
}

if (!val)
return -EIO;
}
} else {
/* If it was only Tx */
if (xfer->rx_buf == NULL) {
sdd->state &= ~TXBUSY;
return 0;
}

switch (sdd->cur_bpw) {
case 32:
ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
xfer->rx_buf, xfer->len / 4);
break;
case 16:
ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
xfer->rx_buf, xfer->len / 2);
break;
default:
ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
xfer->rx_buf, xfer->len);
break;
}
sdd->state &= ~RXBUSY;
}

return 0;
}

static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd,
struct spi_device *spi)
{
struct s3c64xx_spi_csinfo *cs = spi->controller_data;

if (sdd->tgl_spi == spi)
sdd->tgl_spi = NULL;

cs->set_level(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1);
}

static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
void __iomem *regs = sdd->regs;
u32 val;

/* Disable Clock */
if (sci->clk_from_cmu) {
clk_disable(sdd->src_clk);
} else {
val = readl(regs + S3C64XX_SPI_CLK_CFG);
val &= ~S3C64XX_SPI_ENCLK_ENABLE;
writel(val, regs + S3C64XX_SPI_CLK_CFG);
}

/* Set Polarity and Phase */
val = readl(regs + S3C64XX_SPI_CH_CFG);
val &= ~(S3C64XX_SPI_CH_SLAVE |
S3C64XX_SPI_CPOL_L |
S3C64XX_SPI_CPHA_B);

if (sdd->cur_mode & SPI_CPOL)
val |= S3C64XX_SPI_CPOL_L;

if (sdd->cur_mode & SPI_CPHA)
val |= S3C64XX_SPI_CPHA_B;

writel(val, regs + S3C64XX_SPI_CH_CFG);

/* Set Channel & DMA Mode */
val = readl(regs + S3C64XX_SPI_MODE_CFG);
val &= ~(S3C64XX_SPI_MODE_BUS_TSZ_MASK
| S3C64XX_SPI_MODE_CH_TSZ_MASK);

switch (sdd->cur_bpw) {
case 32:
val |= S3C64XX_SPI_MODE_BUS_TSZ_WORD;
val |= S3C64XX_SPI_MODE_CH_TSZ_WORD;
break;
case 16:
val |= S3C64XX_SPI_MODE_BUS_TSZ_HALFWORD;
val |= S3C64XX_SPI_MODE_CH_TSZ_HALFWORD;
break;
default:
val |= S3C64XX_SPI_MODE_BUS_TSZ_BYTE;
val |= S3C64XX_SPI_MODE_CH_TSZ_BYTE;
break;
}

writel(val, regs + S3C64XX_SPI_MODE_CFG);

if (sci->clk_from_cmu) {
/* Configure Clock */
/* There is half-multiplier before the SPI */
clk_set_rate(sdd->src_clk, sdd->cur_speed * 2);
/* Enable Clock */
clk_enable(sdd->src_clk);
} else {
/* Configure Clock */
val = readl(regs + S3C64XX_SPI_CLK_CFG);
val &= ~S3C64XX_SPI_PSR_MASK;
val |= ((clk_get_rate(sdd->src_clk) / sdd->cur_speed / 2 - 1)
& S3C64XX_SPI_PSR_MASK);
writel(val, regs + S3C64XX_SPI_CLK_CFG);

/* Enable Clock */
val = readl(regs + S3C64XX_SPI_CLK_CFG);
val |= S3C64XX_SPI_ENCLK_ENABLE;
writel(val, regs + S3C64XX_SPI_CLK_CFG);
}
}

static void s3c64xx_spi_dma_rxcb(struct s3c2410_dma_chan *chan, void *buf_id,
int size, enum s3c2410_dma_buffresult res)
{
struct s3c64xx_spi_driver_data *sdd = buf_id;
unsigned long flags;

spin_lock_irqsave(&sdd->lock, flags);

if (res == S3C2410_RES_OK)
sdd->state &= ~RXBUSY;
else
dev_err(&sdd->pdev->dev, "DmaAbrtRx-%d\n", size);

/* If the other done */
if (!(sdd->state & TXBUSY))
complete(&sdd->xfer_completion);

spin_unlock_irqrestore(&sdd->lock, flags);
}

static void s3c64xx_spi_dma_txcb(struct s3c2410_dma_chan *chan, void *buf_id,
int size, enum s3c2410_dma_buffresult res)
{
struct s3c64xx_spi_driver_data *sdd = buf_id;
unsigned long flags;

spin_lock_irqsave(&sdd->lock, flags);

if (res == S3C2410_RES_OK)
sdd->state &= ~TXBUSY;
else
dev_err(&sdd->pdev->dev, "DmaAbrtTx-%d \n", size);

/* If the other done */
if (!(sdd->state & RXBUSY))
complete(&sdd->xfer_completion);

spin_unlock_irqrestore(&sdd->lock, flags);
}

#define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)

static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd,
struct spi_message *msg)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
struct device *dev = &sdd->pdev->dev;
struct spi_transfer *xfer;

if (msg->is_dma_mapped)
return 0;

/* First mark all xfer unmapped */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {
xfer->rx_dma = XFER_DMAADDR_INVALID;
xfer->tx_dma = XFER_DMAADDR_INVALID;
}

/* Map until end or first fail */
list_for_each_entry(xfer, &msg->transfers, transfer_list) {

if (xfer->len <= ((sci->fifo_lvl_mask >> 1) + 1))
continue;

if (xfer->tx_buf != NULL) {
xfer->tx_dma = dma_map_single(dev,
(void *)xfer->tx_buf, xfer->len,
DMA_TO_DEVICE);
if (dma_mapping_error(dev, xfer->tx_dma)) {
dev_err(dev, "dma_map_single Tx failed\n");
xfer->tx_dma = XFER_DMAADDR_INVALID;
return -ENOMEM;
}
}

if (xfer->rx_buf != NULL) {
xfer->rx_dma = dma_map_single(dev, xfer->rx_buf,
xfer->len, DMA_FROM_DEVICE);
if (dma_mapping_error(dev, xfer->rx_dma)) {
dev_err(dev, "dma_map_single Rx failed\n");
dma_unmap_single(dev, xfer->tx_dma,
xfer->len, DMA_TO_DEVICE);
xfer->tx_dma = XFER_DMAADDR_INVALID;
xfer->rx_dma = XFER_DMAADDR_INVALID;
return -ENOMEM;
}
}
}

return 0;
}

static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd,
struct spi_message *msg)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
struct device *dev = &sdd->pdev->dev;
struct spi_transfer *xfer;

if (msg->is_dma_mapped)
return;

list_for_each_entry(xfer, &msg->transfers, transfer_list) {

if (xfer->len <= ((sci->fifo_lvl_mask >> 1) + 1))
continue;

if (xfer->rx_buf != NULL
&& xfer->rx_dma != XFER_DMAADDR_INVALID)
dma_unmap_single(dev, xfer->rx_dma,
xfer->len, DMA_FROM_DEVICE);

if (xfer->tx_buf != NULL
&& xfer->tx_dma != XFER_DMAADDR_INVALID)
dma_unmap_single(dev, xfer->tx_dma,
xfer->len, DMA_TO_DEVICE);
}
}

static void handle_msg(struct s3c64xx_spi_driver_data *sdd,
struct spi_message *msg)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
struct spi_device *spi = msg->spi;
struct s3c64xx_spi_csinfo *cs = spi->controller_data;
struct spi_transfer *xfer;
int status = 0, cs_toggle = 0;
u32 speed;
u8 bpw;

/* If Master's(controller) state differs from that needed by Slave */
if (sdd->cur_speed != spi->max_speed_hz
|| sdd->cur_mode != spi->mode
|| sdd->cur_bpw != spi->bits_per_word) {
sdd->cur_bpw = spi->bits_per_word;
sdd->cur_speed = spi->max_speed_hz;
sdd->cur_mode = spi->mode;
s3c64xx_spi_config(sdd);
}

/* Map all the transfers if needed */
if (s3c64xx_spi_map_mssg(sdd, msg)) {
dev_err(&spi->dev,
"Xfer: Unable to map message buffers!\n");
status = -ENOMEM;
goto out;
}

/* Configure feedback delay */
writel(cs->fb_delay & 0x3, sdd->regs + S3C64XX_SPI_FB_CLK);

list_for_each_entry(xfer, &msg->transfers, transfer_list) {

unsigned long flags;
int use_dma;

INIT_COMPLETION(sdd->xfer_completion);

/* Only BPW and Speed may change across transfers */
bpw = xfer->bits_per_word ? : spi->bits_per_word;
speed = xfer->speed_hz ? : spi->max_speed_hz;

if (xfer->len % (bpw / 8)) {
dev_err(&spi->dev,
"Xfer length(%u) not a multiple of word size(%u)\n",
xfer->len, bpw / 8);
status = -EIO;
goto out;
}

if (bpw != sdd->cur_bpw || speed != sdd->cur_speed) {
sdd->cur_bpw = bpw;
sdd->cur_speed = speed;
s3c64xx_spi_config(sdd);
}

/* Polling method for xfers not bigger than FIFO capacity */
if (xfer->len <= ((sci->fifo_lvl_mask >> 1) + 1))
use_dma = 0;
else
use_dma = 1;

spin_lock_irqsave(&sdd->lock, flags);

/* Pending only which is to be done */
sdd->state &= ~RXBUSY;
sdd->state &= ~TXBUSY;

enable_datapath(sdd, spi, xfer, use_dma);

/* Slave Select */
enable_cs(sdd, spi);

/* Start the signals */
S3C64XX_SPI_ACT(sdd);

spin_unlock_irqrestore(&sdd->lock, flags);

status = wait_for_xfer(sdd, xfer, use_dma);

/* Quiese the signals */
S3C64XX_SPI_DEACT(sdd);

if (status) {
dev_err(&spi->dev, "I/O Error: "
"rx-%d tx-%d res:rx-%c tx-%c len-%d\n",
xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
(sdd->state & RXBUSY) ? 'f' : 'p',
(sdd->state & TXBUSY) ? 'f' : 'p',
xfer->len);

if (use_dma) {
if (xfer->tx_buf != NULL
&& (sdd->state & TXBUSY))
s3c2410_dma_ctrl(sdd->tx_dmach,
S3C2410_DMAOP_FLUSH);
if (xfer->rx_buf != NULL
&& (sdd->state & RXBUSY))
s3c2410_dma_ctrl(sdd->rx_dmach,
S3C2410_DMAOP_FLUSH);
}

goto out;
}

if (xfer->delay_usecs)
udelay(xfer->delay_usecs);

if (xfer->cs_change) {
/* Hint that the next mssg is gonna be
for the same device */
if (list_is_last(&xfer->transfer_list,
&msg->transfers))
cs_toggle = 1;
else
disable_cs(sdd, spi);
}

msg->actual_length += xfer->len;

flush_fifo(sdd);
}

out:
if (!cs_toggle || status)
disable_cs(sdd, spi);
else
sdd->tgl_spi = spi;

s3c64xx_spi_unmap_mssg(sdd, msg);

msg->status = status;

if (msg->complete)
msg->complete(msg->context);
}

static int acquire_dma(struct s3c64xx_spi_driver_data *sdd)
{
if (s3c2410_dma_request(sdd->rx_dmach,
&s3c64xx_spi_dma_client, NULL) < 0) {
dev_err(&sdd->pdev->dev, "cannot get RxDMA\n");
return 0;
}
s3c2410_dma_set_buffdone_fn(sdd->rx_dmach, s3c64xx_spi_dma_rxcb);
s3c2410_dma_devconfig(sdd->rx_dmach, S3C2410_DMASRC_HW,
sdd->sfr_start + S3C64XX_SPI_RX_DATA);

if (s3c2410_dma_request(sdd->tx_dmach,
&s3c64xx_spi_dma_client, NULL) < 0) {
dev_err(&sdd->pdev->dev, "cannot get TxDMA\n");
s3c2410_dma_free(sdd->rx_dmach, &s3c64xx_spi_dma_client);
return 0;
}
s3c2410_dma_set_buffdone_fn(sdd->tx_dmach, s3c64xx_spi_dma_txcb);
s3c2410_dma_devconfig(sdd->tx_dmach, S3C2410_DMASRC_MEM,
sdd->sfr_start + S3C64XX_SPI_TX_DATA);

return 1;
}

static void s3c64xx_spi_work(struct work_struct *work)
{
struct s3c64xx_spi_driver_data *sdd = container_of(work,
struct s3c64xx_spi_driver_data, work);
unsigned long flags;

/* Acquire DMA channels */
while (!acquire_dma(sdd))
msleep(10);

spin_lock_irqsave(&sdd->lock, flags);

while (!list_empty(&sdd->queue)
&& !(sdd->state & SUSPND)) {

struct spi_message *msg;

msg = container_of(sdd->queue.next, struct spi_message, queue);

list_del_init(&msg->queue);

/* Set Xfer busy flag */
sdd->state |= SPIBUSY;

spin_unlock_irqrestore(&sdd->lock, flags);

handle_msg(sdd, msg);

spin_lock_irqsave(&sdd->lock, flags);

sdd->state &= ~SPIBUSY;
}

spin_unlock_irqrestore(&sdd->lock, flags);

/* Free DMA channels */
s3c2410_dma_free(sdd->tx_dmach, &s3c64xx_spi_dma_client);
s3c2410_dma_free(sdd->rx_dmach, &s3c64xx_spi_dma_client);
}

static int s3c64xx_spi_transfer(struct spi_device *spi,
struct spi_message *msg)
{
struct s3c64xx_spi_driver_data *sdd;
unsigned long flags;

sdd = spi_master_get_devdata(spi->master);

spin_lock_irqsave(&sdd->lock, flags);

if (sdd->state & SUSPND) {
spin_unlock_irqrestore(&sdd->lock, flags);
return -ESHUTDOWN;
}

msg->status = -EINPROGRESS;
msg->actual_length = 0;

list_add_tail(&msg->queue, &sdd->queue);

queue_work(sdd->workqueue, &sdd->work);

spin_unlock_irqrestore(&sdd->lock, flags);

return 0;
}

/*
* Here we only check the validity of requested configuration
* and save the configuration in a local data-structure.
* The controller is actually configured only just before we
* get a message to transfer.
*/
static int s3c64xx_spi_setup(struct spi_device *spi)
{
struct s3c64xx_spi_csinfo *cs = spi->controller_data;
struct s3c64xx_spi_driver_data *sdd;
struct s3c64xx_spi_info *sci;
struct spi_message *msg;
unsigned long flags;
int err = 0;

if (cs == NULL || cs->set_level == NULL) {
dev_err(&spi->dev, "No CS for SPI(%d)\n", spi->chip_select);
return -ENODEV;
}

sdd = spi_master_get_devdata(spi->master);
sci = sdd->cntrlr_info;

spin_lock_irqsave(&sdd->lock, flags);

list_for_each_entry(msg, &sdd->queue, queue) {
/* Is some mssg is already queued for this device */
if (msg->spi == spi) {
dev_err(&spi->dev,
"setup: attempt while mssg in queue!\n");
spin_unlock_irqrestore(&sdd->lock, flags);
return -EBUSY;
}
}

if (sdd->state & SUSPND) {
spin_unlock_irqrestore(&sdd->lock, flags);
dev_err(&spi->dev,
"setup: SPI-%d not active!\n", spi->master->bus_num);
return -ESHUTDOWN;
}

spin_unlock_irqrestore(&sdd->lock, flags);

if (spi->bits_per_word != 8
&& spi->bits_per_word != 16
&& spi->bits_per_word != 32) {
dev_err(&spi->dev, "setup: %dbits/wrd not supported!\n",
spi->bits_per_word);
err = -EINVAL;
goto setup_exit;
}

/* Check if we can provide the requested rate */
if (!sci->clk_from_cmu) {
u32 psr, speed;

/* Max possible */
speed = clk_get_rate(sdd->src_clk) / 2 / (0 + 1);

if (spi->max_speed_hz > speed)
spi->max_speed_hz = speed;

psr = clk_get_rate(sdd->src_clk) / 2 / spi->max_speed_hz - 1;
psr &= S3C64XX_SPI_PSR_MASK;
if (psr == S3C64XX_SPI_PSR_MASK)
psr--;

speed = clk_get_rate(sdd->src_clk) / 2 / (psr + 1);
if (spi->max_speed_hz < speed) {
if (psr+1 < S3C64XX_SPI_PSR_MASK) {
psr++;
} else {
err = -EINVAL;
goto setup_exit;
}
}

speed = clk_get_rate(sdd->src_clk) / 2 / (psr + 1);
if (spi->max_speed_hz >= speed)
spi->max_speed_hz = speed;
else
err = -EINVAL;
}

setup_exit:

/* setup() returns with device de-selected */
disable_cs(sdd, spi);

return err;
}

static void s3c64xx_spi_hwinit(struct s3c64xx_spi_driver_data *sdd, int channel)
{
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
void __iomem *regs = sdd->regs;
unsigned int val;

sdd->cur_speed = 0;

S3C64XX_SPI_DEACT(sdd);

/* Disable Interrupts - we use Polling if not DMA mode */
writel(0, regs + S3C64XX_SPI_INT_EN);

if (!sci->clk_from_cmu)
writel(sci->src_clk_nr << S3C64XX_SPI_CLKSEL_SRCSHFT,
regs + S3C64XX_SPI_CLK_CFG);
writel(0, regs + S3C64XX_SPI_MODE_CFG);
writel(0, regs + S3C64XX_SPI_PACKET_CNT);

/* Clear any irq pending bits */
writel(readl(regs + S3C64XX_SPI_PENDING_CLR),
regs + S3C64XX_SPI_PENDING_CLR);

writel(0, regs + S3C64XX_SPI_SWAP_CFG);

val = readl(regs + S3C64XX_SPI_MODE_CFG);
val &= ~S3C64XX_SPI_MODE_4BURST;
val &= ~(S3C64XX_SPI_MAX_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
val |= (S3C64XX_SPI_TRAILCNT << S3C64XX_SPI_TRAILCNT_OFF);
writel(val, regs + S3C64XX_SPI_MODE_CFG);

flush_fifo(sdd);
}

static int __init s3c64xx_spi_probe(struct platform_device *pdev)
{
struct resource *mem_res, *dmatx_res, *dmarx_res;
struct s3c64xx_spi_driver_data *sdd;
struct s3c64xx_spi_info *sci;
struct spi_master *master;
int ret;

if (pdev->id < 0) {
dev_err(&pdev->dev,
"Invalid platform device id-%d\n", pdev->id);
return -ENODEV;
}

if (pdev->dev.platform_data == NULL) {
dev_err(&pdev->dev, "platform_data missing!\n");
return -ENODEV;
}

sci = pdev->dev.platform_data;
if (!sci->src_clk_name) {
dev_err(&pdev->dev,
"Board init must call s3c64xx_spi_set_info()\n");
return -EINVAL;
}

/* Check for availability of necessary resource */

dmatx_res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
if (dmatx_res == NULL) {
dev_err(&pdev->dev, "Unable to get SPI-Tx dma resource\n");
return -ENXIO;
}

dmarx_res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
if (dmarx_res == NULL) {
dev_err(&pdev->dev, "Unable to get SPI-Rx dma resource\n");
return -ENXIO;
}

mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (mem_res == NULL) {
dev_err(&pdev->dev, "Unable to get SPI MEM resource\n");
return -ENXIO;
}

master = spi_alloc_master(&pdev->dev,
sizeof(struct s3c64xx_spi_driver_data));
if (master == NULL) {
dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
return -ENOMEM;
}

platform_set_drvdata(pdev, master);

sdd = spi_master_get_devdata(master);
sdd->master = master;
sdd->cntrlr_info = sci;
sdd->pdev = pdev;
sdd->sfr_start = mem_res->start;
sdd->tx_dmach = dmatx_res->start;
sdd->rx_dmach = dmarx_res->start;

sdd->cur_bpw = 8;

master->bus_num = pdev->id;
master->setup = s3c64xx_spi_setup;
master->transfer = s3c64xx_spi_transfer;
master->num_chipselect = sci->num_cs;
master->dma_alignment = 8;
/* the spi->mode bits understood by this driver: */
master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;

if (request_mem_region(mem_res->start,
resource_size(mem_res), pdev->name) == NULL) {
dev_err(&pdev->dev, "Req mem region failed\n");
ret = -ENXIO;
goto err0;
}

sdd->regs = ioremap(mem_res->start, resource_size(mem_res));
if (sdd->regs == NULL) {
dev_err(&pdev->dev, "Unable to remap IO\n");
ret = -ENXIO;
goto err1;
}

if (sci->cfg_gpio == NULL || sci->cfg_gpio(pdev)) {
dev_err(&pdev->dev, "Unable to config gpio\n");
ret = -EBUSY;
goto err2;
}

/* Setup clocks */
sdd->clk = clk_get(&pdev->dev, "spi");
if (IS_ERR(sdd->clk)) {
dev_err(&pdev->dev, "Unable to acquire clock 'spi'\n");
ret = PTR_ERR(sdd->clk);
goto err3;
}

if (clk_enable(sdd->clk)) {
dev_err(&pdev->dev, "Couldn't enable clock 'spi'\n");
ret = -EBUSY;
goto err4;
}

sdd->src_clk = clk_get(&pdev->dev, sci->src_clk_name);
if (IS_ERR(sdd->src_clk)) {
dev_err(&pdev->dev,
"Unable to acquire clock '%s'\n", sci->src_clk_name);
ret = PTR_ERR(sdd->src_clk);
goto err5;
}

if (clk_enable(sdd->src_clk)) {
dev_err(&pdev->dev, "Couldn't enable clock '%s'\n",
sci->src_clk_name);
ret = -EBUSY;
goto err6;
}

sdd->workqueue = create_singlethread_workqueue(
dev_name(master->dev.parent));
if (sdd->workqueue == NULL) {
dev_err(&pdev->dev, "Unable to create workqueue\n");
ret = -ENOMEM;
goto err7;
}

/* Setup Deufult Mode */
s3c64xx_spi_hwinit(sdd, pdev->id);

spin_lock_init(&sdd->lock);
init_completion(&sdd->xfer_completion);
INIT_WORK(&sdd->work, s3c64xx_spi_work);
INIT_LIST_HEAD(&sdd->queue);

if (spi_register_master(master)) {
dev_err(&pdev->dev, "cannot register SPI master\n");
ret = -EBUSY;
goto err8;
}

dev_dbg(&pdev->dev, "Samsung SoC SPI Driver loaded for Bus SPI-%d "
"with %d Slaves attached\n",
pdev->id, master->num_chipselect);
dev_dbg(&pdev->dev, "\tIOmem=[0x%x-0x%x]\tDMA=[Rx-%d, Tx-%d]\n",
mem_res->end, mem_res->start,
sdd->rx_dmach, sdd->tx_dmach);

return 0;

err8:
destroy_workqueue(sdd->workqueue);
err7:
clk_disable(sdd->src_clk);
err6:
clk_put(sdd->src_clk);
err5:
clk_disable(sdd->clk);
err4:
clk_put(sdd->clk);
err3:
err2:
iounmap((void *) sdd->regs);
err1:
release_mem_region(mem_res->start, resource_size(mem_res));
err0:
platform_set_drvdata(pdev, NULL);
spi_master_put(master);

return ret;
}

static int s3c64xx_spi_remove(struct platform_device *pdev)
{
struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
struct resource *mem_res;
unsigned long flags;

spin_lock_irqsave(&sdd->lock, flags);
sdd->state |= SUSPND;
spin_unlock_irqrestore(&sdd->lock, flags);

while (sdd->state & SPIBUSY)
msleep(10);

spi_unregister_master(master);

destroy_workqueue(sdd->workqueue);

clk_disable(sdd->src_clk);
clk_put(sdd->src_clk);

clk_disable(sdd->clk);
clk_put(sdd->clk);

iounmap((void *) sdd->regs);

mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (mem_res != NULL)
release_mem_region(mem_res->start, resource_size(mem_res));

platform_set_drvdata(pdev, NULL);
spi_master_put(master);

return 0;
}

#ifdef CONFIG_PM
static int s3c64xx_spi_suspend(struct platform_device *pdev, pm_message_t state)
{
struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
unsigned long flags;

spin_lock_irqsave(&sdd->lock, flags);
sdd->state |= SUSPND;
spin_unlock_irqrestore(&sdd->lock, flags);

while (sdd->state & SPIBUSY)
msleep(10);

/* Disable the clock */
clk_disable(sdd->src_clk);
clk_disable(sdd->clk);

sdd->cur_speed = 0; /* Output Clock is stopped */

return 0;
}

static int s3c64xx_spi_resume(struct platform_device *pdev)
{
struct spi_master *master = spi_master_get(platform_get_drvdata(pdev));
struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
struct s3c64xx_spi_info *sci = sdd->cntrlr_info;
unsigned long flags;

sci->cfg_gpio(pdev);

/* Enable the clock */
clk_enable(sdd->src_clk);
clk_enable(sdd->clk);

s3c64xx_spi_hwinit(sdd, pdev->id);

spin_lock_irqsave(&sdd->lock, flags);
sdd->state &= ~SUSPND;
spin_unlock_irqrestore(&sdd->lock, flags);

return 0;
}
#else
#define s3c64xx_spi_suspend NULL
#define s3c64xx_spi_resume NULL
#endif /* CONFIG_PM */

static struct platform_driver s3c64xx_spi_driver = {
.driver = {
.name = "s3c64xx-spi",
.owner = THIS_MODULE,
},
.remove = s3c64xx_spi_remove,
.suspend = s3c64xx_spi_suspend,
.resume = s3c64xx_spi_resume,
};
MODULE_ALIAS("platform:s3c64xx-spi");

static int __init s3c64xx_spi_init(void)
{
return platform_driver_probe(&s3c64xx_spi_driver, s3c64xx_spi_probe);
}
subsys_initcall(s3c64xx_spi_init);

static void __exit s3c64xx_spi_exit(void)
{
platform_driver_unregister(&s3c64xx_spi_driver);
}
module_exit(s3c64xx_spi_exit);

MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
MODULE_DESCRIPTION("S3C64XX SPI Controller Driver");
MODULE_LICENSE("GPL");
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