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spi-s3c64xx.c
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spi-s3c64xx.c
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// SPDX-License-Identifier: GPL-2.0+
//
// Copyright (c) 2009 Samsung Electronics Co., Ltd.
// Jaswinder Singh <jassi.brar@samsung.com>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/of.h>
#include <linux/platform_data/spi-s3c64xx.h>
#define MAX_SPI_PORTS 12
#define S3C64XX_SPI_QUIRK_CS_AUTO (1 << 1)
#define AUTOSUSPEND_TIMEOUT 2000
/* 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_CS_REG 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_RX_RDY_LVL GENMASK(16, 11)
#define S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT 11
#define S3C64XX_SPI_MODE_SELF_LOOPBACK (1<<3)
#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_CS_NSC_CNT_2 (2<<4)
#define S3C64XX_SPI_CS_AUTO (1<<1)
#define S3C64XX_SPI_CS_SIG_INACT (1<<0)
#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_PACKET_CNT_MASK GENMASK(15, 0)
#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 FIFO_LVL_MASK(i) ((i)->port_conf->fifo_lvl_mask[i->port_id])
#define S3C64XX_SPI_ST_TX_DONE(v, i) (((v) & \
(1 << (i)->port_conf->tx_st_done)) ? 1 : 0)
#define TX_FIFO_LVL(v, i) (((v) >> 6) & FIFO_LVL_MASK(i))
#define RX_FIFO_LVL(v, i) (((v) >> (i)->port_conf->rx_lvl_offset) & \
FIFO_LVL_MASK(i))
#define FIFO_DEPTH(i) ((FIFO_LVL_MASK(i) >> 1) + 1)
#define S3C64XX_SPI_MAX_TRAILCNT 0x3ff
#define S3C64XX_SPI_TRAILCNT_OFF 19
#define S3C64XX_SPI_TRAILCNT S3C64XX_SPI_MAX_TRAILCNT
#define S3C64XX_SPI_POLLING_SIZE 32
#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
#define is_polling(x) (x->cntrlr_info->polling)
#define RXBUSY (1<<2)
#define TXBUSY (1<<3)
struct s3c64xx_spi_dma_data {
struct dma_chan *ch;
dma_cookie_t cookie;
enum dma_transfer_direction direction;
};
/**
* struct s3c64xx_spi_port_config - SPI Controller hardware info
* @fifo_lvl_mask: Bit-mask for {TX|RX}_FIFO_LVL bits in SPI_STATUS register.
* @rx_lvl_offset: Bit offset of RX_FIFO_LVL bits in SPI_STATUS regiter.
* @tx_st_done: Bit offset of TX_DONE bit in SPI_STATUS regiter.
* @clk_div: Internal clock divider
* @quirks: Bitmask of known quirks
* @high_speed: True, if the controller supports HIGH_SPEED_EN bit.
* @clk_from_cmu: True, if the controller does not include a clock mux and
* prescaler unit.
* @clk_ioclk: True if clock is present on this device
* @has_loopback: True if loopback mode can be supported
*
* The Samsung s3c64xx SPI controller are used on various Samsung SoC's but
* differ in some aspects such as the size of the fifo and spi bus clock
* setup. Such differences are specified to the driver using this structure
* which is provided as driver data to the driver.
*/
struct s3c64xx_spi_port_config {
int fifo_lvl_mask[MAX_SPI_PORTS];
int rx_lvl_offset;
int tx_st_done;
int quirks;
int clk_div;
bool high_speed;
bool clk_from_cmu;
bool clk_ioclk;
bool has_loopback;
};
/**
* 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.
* @ioclk: Pointer to the i/o clock between host and target
* @pdev: Pointer to device's platform device data
* @host: Pointer to the SPI Protocol host.
* @cntrlr_info: Platform specific data for the controller this driver manages.
* @lock: Controller specific lock.
* @state: Set of FLAGS to indicate status.
* @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: Current clock speed
* @rx_dma: Local receive DMA data (e.g. chan and direction)
* @tx_dma: Local transmit DMA data (e.g. chan and direction)
* @port_conf: Local SPI port configuartion data
* @port_id: Port identification number
*/
struct s3c64xx_spi_driver_data {
void __iomem *regs;
struct clk *clk;
struct clk *src_clk;
struct clk *ioclk;
struct platform_device *pdev;
struct spi_controller *host;
struct s3c64xx_spi_info *cntrlr_info;
spinlock_t lock;
unsigned long sfr_start;
struct completion xfer_completion;
unsigned state;
unsigned cur_mode, cur_bpw;
unsigned cur_speed;
struct s3c64xx_spi_dma_data rx_dma;
struct s3c64xx_spi_dma_data tx_dma;
const struct s3c64xx_spi_port_config *port_conf;
unsigned int port_id;
};
static void s3c64xx_flush_fifo(struct s3c64xx_spi_driver_data *sdd)
{
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_RXCH_ON | S3C64XX_SPI_CH_TXCH_ON);
writel(val, regs + S3C64XX_SPI_CH_CFG);
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, sdd) && 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, sdd))
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);
}
static void s3c64xx_spi_dmacb(void *data)
{
struct s3c64xx_spi_driver_data *sdd;
struct s3c64xx_spi_dma_data *dma = data;
unsigned long flags;
if (dma->direction == DMA_DEV_TO_MEM)
sdd = container_of(data,
struct s3c64xx_spi_driver_data, rx_dma);
else
sdd = container_of(data,
struct s3c64xx_spi_driver_data, tx_dma);
spin_lock_irqsave(&sdd->lock, flags);
if (dma->direction == DMA_DEV_TO_MEM) {
sdd->state &= ~RXBUSY;
if (!(sdd->state & TXBUSY))
complete(&sdd->xfer_completion);
} else {
sdd->state &= ~TXBUSY;
if (!(sdd->state & RXBUSY))
complete(&sdd->xfer_completion);
}
spin_unlock_irqrestore(&sdd->lock, flags);
}
static int prepare_dma(struct s3c64xx_spi_dma_data *dma,
struct sg_table *sgt)
{
struct s3c64xx_spi_driver_data *sdd;
struct dma_slave_config config;
struct dma_async_tx_descriptor *desc;
int ret;
memset(&config, 0, sizeof(config));
if (dma->direction == DMA_DEV_TO_MEM) {
sdd = container_of((void *)dma,
struct s3c64xx_spi_driver_data, rx_dma);
config.direction = dma->direction;
config.src_addr = sdd->sfr_start + S3C64XX_SPI_RX_DATA;
config.src_addr_width = sdd->cur_bpw / 8;
config.src_maxburst = 1;
dmaengine_slave_config(dma->ch, &config);
} else {
sdd = container_of((void *)dma,
struct s3c64xx_spi_driver_data, tx_dma);
config.direction = dma->direction;
config.dst_addr = sdd->sfr_start + S3C64XX_SPI_TX_DATA;
config.dst_addr_width = sdd->cur_bpw / 8;
config.dst_maxburst = 1;
dmaengine_slave_config(dma->ch, &config);
}
desc = dmaengine_prep_slave_sg(dma->ch, sgt->sgl, sgt->nents,
dma->direction, DMA_PREP_INTERRUPT);
if (!desc) {
dev_err(&sdd->pdev->dev, "unable to prepare %s scatterlist",
dma->direction == DMA_DEV_TO_MEM ? "rx" : "tx");
return -ENOMEM;
}
desc->callback = s3c64xx_spi_dmacb;
desc->callback_param = dma;
dma->cookie = dmaengine_submit(desc);
ret = dma_submit_error(dma->cookie);
if (ret) {
dev_err(&sdd->pdev->dev, "DMA submission failed");
return -EIO;
}
dma_async_issue_pending(dma->ch);
return 0;
}
static void s3c64xx_spi_set_cs(struct spi_device *spi, bool enable)
{
struct s3c64xx_spi_driver_data *sdd =
spi_controller_get_devdata(spi->controller);
if (sdd->cntrlr_info->no_cs)
return;
if (enable) {
if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) {
writel(0, sdd->regs + S3C64XX_SPI_CS_REG);
} else {
u32 ssel = readl(sdd->regs + S3C64XX_SPI_CS_REG);
ssel |= (S3C64XX_SPI_CS_AUTO |
S3C64XX_SPI_CS_NSC_CNT_2);
writel(ssel, sdd->regs + S3C64XX_SPI_CS_REG);
}
} else {
if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO))
writel(S3C64XX_SPI_CS_SIG_INACT,
sdd->regs + S3C64XX_SPI_CS_REG);
}
}
static int s3c64xx_spi_prepare_transfer(struct spi_controller *spi)
{
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(spi);
if (is_polling(sdd))
return 0;
/* Requests DMA channels */
sdd->rx_dma.ch = dma_request_chan(&sdd->pdev->dev, "rx");
if (IS_ERR(sdd->rx_dma.ch)) {
dev_err(&sdd->pdev->dev, "Failed to get RX DMA channel\n");
sdd->rx_dma.ch = NULL;
return 0;
}
sdd->tx_dma.ch = dma_request_chan(&sdd->pdev->dev, "tx");
if (IS_ERR(sdd->tx_dma.ch)) {
dev_err(&sdd->pdev->dev, "Failed to get TX DMA channel\n");
dma_release_channel(sdd->rx_dma.ch);
sdd->tx_dma.ch = NULL;
sdd->rx_dma.ch = NULL;
return 0;
}
spi->dma_rx = sdd->rx_dma.ch;
spi->dma_tx = sdd->tx_dma.ch;
return 0;
}
static int s3c64xx_spi_unprepare_transfer(struct spi_controller *spi)
{
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(spi);
if (is_polling(sdd))
return 0;
/* Releases DMA channels if they are allocated */
if (sdd->rx_dma.ch && sdd->tx_dma.ch) {
dma_release_channel(sdd->rx_dma.ch);
dma_release_channel(sdd->tx_dma.ch);
sdd->rx_dma.ch = NULL;
sdd->tx_dma.ch = NULL;
}
return 0;
}
static bool s3c64xx_spi_can_dma(struct spi_controller *host,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
if (sdd->rx_dma.ch && sdd->tx_dma.ch) {
return xfer->len > FIFO_DEPTH(sdd);
} else {
return false;
}
}
static int s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
struct spi_transfer *xfer, int dma_mode)
{
void __iomem *regs = sdd->regs;
u32 modecfg, chcfg;
int ret = 0;
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;
ret = prepare_dma(&sdd->tx_dma, &xfer->tx_sg);
} 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 (sdd->port_conf->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);
ret = prepare_dma(&sdd->rx_dma, &xfer->rx_sg);
}
}
if (ret)
return ret;
writel(modecfg, regs + S3C64XX_SPI_MODE_CFG);
writel(chcfg, regs + S3C64XX_SPI_CH_CFG);
return 0;
}
static u32 s3c64xx_spi_wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
int timeout_ms)
{
void __iomem *regs = sdd->regs;
unsigned long val = 1;
u32 status;
u32 max_fifo = FIFO_DEPTH(sdd);
if (timeout_ms)
val = msecs_to_loops(timeout_ms);
do {
status = readl(regs + S3C64XX_SPI_STATUS);
} while (RX_FIFO_LVL(status, sdd) < max_fifo && --val);
/* return the actual received data length */
return RX_FIFO_LVL(status, sdd);
}
static int s3c64xx_wait_for_dma(struct s3c64xx_spi_driver_data *sdd,
struct spi_transfer *xfer)
{
void __iomem *regs = sdd->regs;
unsigned long val;
u32 status;
int ms;
/* millisecs to xfer 'len' bytes @ 'cur_speed' */
ms = xfer->len * 8 * 1000 / sdd->cur_speed;
ms += 30; /* some tolerance */
ms = max(ms, 100); /* minimum timeout */
val = msecs_to_jiffies(ms) + 10;
val = wait_for_completion_timeout(&sdd->xfer_completion, val);
/*
* If the previous xfer was completed within timeout, then
* proceed further else return -EIO.
* 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 (val && !xfer->rx_buf) {
val = msecs_to_loops(10);
status = readl(regs + S3C64XX_SPI_STATUS);
while ((TX_FIFO_LVL(status, sdd)
|| !S3C64XX_SPI_ST_TX_DONE(status, sdd))
&& --val) {
cpu_relax();
status = readl(regs + S3C64XX_SPI_STATUS);
}
}
/* If timed out while checking rx/tx status return error */
if (!val)
return -EIO;
return 0;
}
static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
struct spi_transfer *xfer, bool use_irq)
{
void __iomem *regs = sdd->regs;
unsigned long val;
u32 status;
int loops;
u32 cpy_len;
u8 *buf;
int ms;
unsigned long time_us;
/* microsecs to xfer 'len' bytes @ 'cur_speed' */
time_us = (xfer->len * 8 * 1000 * 1000) / sdd->cur_speed;
ms = (time_us / 1000);
ms += 10; /* some tolerance */
/* sleep during signal transfer time */
status = readl(regs + S3C64XX_SPI_STATUS);
if (RX_FIFO_LVL(status, sdd) < xfer->len)
usleep_range(time_us / 2, time_us);
if (use_irq) {
val = msecs_to_jiffies(ms);
if (!wait_for_completion_timeout(&sdd->xfer_completion, val))
return -EIO;
}
val = msecs_to_loops(ms);
do {
status = readl(regs + S3C64XX_SPI_STATUS);
} while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
if (!val)
return -EIO;
/* If it was only Tx */
if (!xfer->rx_buf) {
sdd->state &= ~TXBUSY;
return 0;
}
/*
* If the receive length is bigger than the controller fifo
* size, calculate the loops and read the fifo as many times.
* loops = length / max fifo size (calculated by using the
* fifo mask).
* For any size less than the fifo size the below code is
* executed atleast once.
*/
loops = xfer->len / FIFO_DEPTH(sdd);
buf = xfer->rx_buf;
do {
/* wait for data to be received in the fifo */
cpy_len = s3c64xx_spi_wait_for_timeout(sdd,
(loops ? ms : 0));
switch (sdd->cur_bpw) {
case 32:
ioread32_rep(regs + S3C64XX_SPI_RX_DATA,
buf, cpy_len / 4);
break;
case 16:
ioread16_rep(regs + S3C64XX_SPI_RX_DATA,
buf, cpy_len / 2);
break;
default:
ioread8_rep(regs + S3C64XX_SPI_RX_DATA,
buf, cpy_len);
break;
}
buf = buf + cpy_len;
} while (loops--);
sdd->state &= ~RXBUSY;
return 0;
}
static int s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
{
void __iomem *regs = sdd->regs;
int ret;
u32 val;
int div = sdd->port_conf->clk_div;
/* Disable Clock */
if (!sdd->port_conf->clk_from_cmu) {
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;
}
if ((sdd->cur_mode & SPI_LOOP) && sdd->port_conf->has_loopback)
val |= S3C64XX_SPI_MODE_SELF_LOOPBACK;
else
val &= ~S3C64XX_SPI_MODE_SELF_LOOPBACK;
writel(val, regs + S3C64XX_SPI_MODE_CFG);
if (sdd->port_conf->clk_from_cmu) {
ret = clk_set_rate(sdd->src_clk, sdd->cur_speed * div);
if (ret)
return ret;
sdd->cur_speed = clk_get_rate(sdd->src_clk) / div;
} 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 / div - 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);
}
return 0;
}
#define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)
static int s3c64xx_spi_prepare_message(struct spi_controller *host,
struct spi_message *msg)
{
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
struct spi_device *spi = msg->spi;
struct s3c64xx_spi_csinfo *cs = spi->controller_data;
/* Configure feedback delay */
if (!cs)
/* No delay if not defined */
writel(0, sdd->regs + S3C64XX_SPI_FB_CLK);
else
writel(cs->fb_delay & 0x3, sdd->regs + S3C64XX_SPI_FB_CLK);
return 0;
}
static size_t s3c64xx_spi_max_transfer_size(struct spi_device *spi)
{
struct spi_controller *ctlr = spi->controller;
return ctlr->can_dma ? S3C64XX_SPI_PACKET_CNT_MASK : SIZE_MAX;
}
static int s3c64xx_spi_transfer_one(struct spi_controller *host,
struct spi_device *spi,
struct spi_transfer *xfer)
{
struct s3c64xx_spi_driver_data *sdd = spi_controller_get_devdata(host);
const unsigned int fifo_len = FIFO_DEPTH(sdd);
const void *tx_buf = NULL;
void *rx_buf = NULL;
int target_len = 0, origin_len = 0;
int use_dma = 0;
bool use_irq = false;
int status;
u32 speed;
u8 bpw;
unsigned long flags;
u32 rdy_lv;
u32 val;
reinit_completion(&sdd->xfer_completion);
/* Only BPW and Speed may change across transfers */
bpw = xfer->bits_per_word;
speed = xfer->speed_hz;
if (bpw != sdd->cur_bpw || speed != sdd->cur_speed) {
sdd->cur_bpw = bpw;
sdd->cur_speed = speed;
sdd->cur_mode = spi->mode;
status = s3c64xx_spi_config(sdd);
if (status)
return status;
}
if (!is_polling(sdd) && (xfer->len > fifo_len) &&
sdd->rx_dma.ch && sdd->tx_dma.ch) {
use_dma = 1;
} else if (xfer->len >= fifo_len) {
tx_buf = xfer->tx_buf;
rx_buf = xfer->rx_buf;
origin_len = xfer->len;
target_len = xfer->len;
xfer->len = fifo_len - 1;
}
do {
/* transfer size is greater than 32, change to IRQ mode */
if (!use_dma && xfer->len > S3C64XX_SPI_POLLING_SIZE)
use_irq = true;
if (use_irq) {
reinit_completion(&sdd->xfer_completion);
rdy_lv = xfer->len;
/* Setup RDY_FIFO trigger Level
* RDY_LVL =
* fifo_lvl up to 64 byte -> N bytes
* 128 byte -> RDY_LVL * 2 bytes
* 256 byte -> RDY_LVL * 4 bytes
*/
if (fifo_len == 128)
rdy_lv /= 2;
else if (fifo_len == 256)
rdy_lv /= 4;
val = readl(sdd->regs + S3C64XX_SPI_MODE_CFG);
val &= ~S3C64XX_SPI_MODE_RX_RDY_LVL;
val |= (rdy_lv << S3C64XX_SPI_MODE_RX_RDY_LVL_SHIFT);
writel(val, sdd->regs + S3C64XX_SPI_MODE_CFG);
/* Enable FIFO_RDY_EN IRQ */
val = readl(sdd->regs + S3C64XX_SPI_INT_EN);
writel((val | S3C64XX_SPI_INT_RX_FIFORDY_EN),
sdd->regs + S3C64XX_SPI_INT_EN);
}
spin_lock_irqsave(&sdd->lock, flags);
/* Pending only which is to be done */
sdd->state &= ~RXBUSY;
sdd->state &= ~TXBUSY;
/* Start the signals */
s3c64xx_spi_set_cs(spi, true);
status = s3c64xx_enable_datapath(sdd, xfer, use_dma);
spin_unlock_irqrestore(&sdd->lock, flags);
if (status) {
dev_err(&spi->dev, "failed to enable data path for transfer: %d\n", status);
break;
}
if (use_dma)
status = s3c64xx_wait_for_dma(sdd, xfer);
else
status = s3c64xx_wait_for_pio(sdd, xfer, use_irq);
if (status) {
dev_err(&spi->dev,
"I/O Error: rx-%d tx-%d rx-%c tx-%c len-%d dma-%d res-(%d)\n",
xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0,
(sdd->state & RXBUSY) ? 'f' : 'p',
(sdd->state & TXBUSY) ? 'f' : 'p',
xfer->len, use_dma ? 1 : 0, status);
if (use_dma) {
struct dma_tx_state s;
if (xfer->tx_buf && (sdd->state & TXBUSY)) {
dmaengine_pause(sdd->tx_dma.ch);
dmaengine_tx_status(sdd->tx_dma.ch, sdd->tx_dma.cookie, &s);
dmaengine_terminate_all(sdd->tx_dma.ch);
dev_err(&spi->dev, "TX residue: %d\n", s.residue);
}
if (xfer->rx_buf && (sdd->state & RXBUSY)) {
dmaengine_pause(sdd->rx_dma.ch);
dmaengine_tx_status(sdd->rx_dma.ch, sdd->rx_dma.cookie, &s);
dmaengine_terminate_all(sdd->rx_dma.ch);
dev_err(&spi->dev, "RX residue: %d\n", s.residue);
}
}
} else {
s3c64xx_flush_fifo(sdd);
}
if (target_len > 0) {
target_len -= xfer->len;
if (xfer->tx_buf)
xfer->tx_buf += xfer->len;
if (xfer->rx_buf)
xfer->rx_buf += xfer->len;
if (target_len >= fifo_len)
xfer->len = fifo_len - 1;
else
xfer->len = target_len;
}
} while (target_len > 0);
if (origin_len) {
/* Restore original xfer buffers and length */
xfer->tx_buf = tx_buf;
xfer->rx_buf = rx_buf;
xfer->len = origin_len;
}
return status;
}
static struct s3c64xx_spi_csinfo *s3c64xx_get_target_ctrldata(
struct spi_device *spi)
{
struct s3c64xx_spi_csinfo *cs;
struct device_node *target_np, *data_np = NULL;
u32 fb_delay = 0;
target_np = spi->dev.of_node;
if (!target_np) {
dev_err(&spi->dev, "device node not found\n");
return ERR_PTR(-EINVAL);
}
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return ERR_PTR(-ENOMEM);
data_np = of_get_child_by_name(target_np, "controller-data");
if (!data_np) {
dev_info(&spi->dev, "feedback delay set to default (0)\n");
return cs;
}
of_property_read_u32(data_np, "samsung,spi-feedback-delay", &fb_delay);
cs->fb_delay = fb_delay;
of_node_put(data_np);
return cs;
}
/*
* 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;
int err;
int div;
sdd = spi_controller_get_devdata(spi->controller);
if (spi->dev.of_node) {
cs = s3c64xx_get_target_ctrldata(spi);
spi->controller_data = cs;
}
/* NULL is fine, we just avoid using the FB delay (=0) */
if (IS_ERR(cs)) {
dev_err(&spi->dev, "No CS for SPI(%d)\n", spi_get_chipselect(spi, 0));
return -ENODEV;
}
if (!spi_get_ctldata(spi))
spi_set_ctldata(spi, cs);
pm_runtime_get_sync(&sdd->pdev->dev);
div = sdd->port_conf->clk_div;
/* Check if we can provide the requested rate */
if (!sdd->port_conf->clk_from_cmu) {
u32 psr, speed;
/* Max possible */
speed = clk_get_rate(sdd->src_clk) / div / (0 + 1);
if (spi->max_speed_hz > speed)
spi->max_speed_hz = speed;
psr = clk_get_rate(sdd->src_clk) / div / spi->max_speed_hz - 1;
psr &= S3C64XX_SPI_PSR_MASK;
if (psr == S3C64XX_SPI_PSR_MASK)
psr--;
speed = clk_get_rate(sdd->src_clk) / div / (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) / div / (psr + 1);
if (spi->max_speed_hz >= speed) {
spi->max_speed_hz = speed;
} else {
dev_err(&spi->dev, "Can't set %dHz transfer speed\n",
spi->max_speed_hz);
err = -EINVAL;
goto setup_exit;
}
}
pm_runtime_mark_last_busy(&sdd->pdev->dev);
pm_runtime_put_autosuspend(&sdd->pdev->dev);
s3c64xx_spi_set_cs(spi, false);
return 0;
setup_exit:
pm_runtime_mark_last_busy(&sdd->pdev->dev);
pm_runtime_put_autosuspend(&sdd->pdev->dev);
/* setup() returns with device de-selected */
s3c64xx_spi_set_cs(spi, false);