Add eDMA receive and send mode support.
Support to read and write data larger than 256 bytes in one frame.
Signed-off-by: Clark Wang <xiaoning.wang@xxxxxxx>
Reviewed-by: Li Jun <jun.li@xxxxxxx>
---
V2 changes:
- change marco I2C_USE_PIO to DMA_ERR_I2C_USE_PIO. It is a error code defined
in this driver to
---
drivers/i2c/busses/i2c-imx-lpi2c.c | 290 ++++++++++++++++++++++++++++-
1 file changed, 288 insertions(+), 2 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
index c2f8e49660ea..d1a56d52f19f 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -8,6 +8,8 @@
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/i2c.h>
@@ -31,6 +33,7 @@
#define LPI2C_MCR 0x10 /* i2c contrl register */
#define LPI2C_MSR 0x14 /* i2c status register */
#define LPI2C_MIER 0x18 /* i2c interrupt enable */
+#define LPI2C_MDER 0x1C /* i2c DMA enable */
#define LPI2C_MCFGR0 0x20 /* i2c master configuration */
#define LPI2C_MCFGR1 0x24 /* i2c master configuration */
#define LPI2C_MCFGR2 0x28 /* i2c master configuration */
@@ -72,11 +75,15 @@
#define MCFGR1_AUTOSTOP BIT(8)
#define MCFGR1_IGNACK BIT(9)
#define MRDR_RXEMPTY BIT(14)
+#define MDER_TDDE BIT(0)
+#define MDER_RDDE BIT(1)
#define I2C_CLK_RATIO 24 / 59
#define CHUNK_DATA 256
#define I2C_PM_TIMEOUT 1000 /* ms */
+#define I2C_DMA_THRESHOLD 16 /* bytes */
+#define DMA_ERR_I2C_USE_PIO (-150)
enum lpi2c_imx_mode {
STANDARD, /* <=100Kbps */
@@ -95,6 +102,7 @@ enum lpi2c_imx_pincfg {
struct lpi2c_imx_struct {
struct i2c_adapter adapter;
+ resource_size_t phy_addr;
int irq;
struct clk *clk_per;
struct clk *clk_ipg;
@@ -114,6 +122,17 @@ struct lpi2c_imx_struct {
struct pinctrl *pinctrl;
struct pinctrl_state *pinctrl_pins_default;
struct pinctrl_state *pinctrl_pins_gpio;
+
+ bool can_use_dma;
+ bool using_dma;
+ bool xferred;
+ struct i2c_msg *msg;
+ dma_addr_t dma_addr;
+ struct dma_chan *dma_tx;
+ struct dma_chan *dma_rx;
+ enum dma_data_direction dma_direction;
+ u8 *dma_buf;
+ unsigned int dma_len;
};
static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
@@ -289,6 +308,9 @@ static int lpi2c_imx_master_enable(struct lpi2c_imx_struct *lpi2c_imx)
if (ret)
goto rpm_put;
+ if (lpi2c_imx->can_use_dma)
+ writel(MDER_TDDE | MDER_RDDE, lpi2c_imx->base + LPI2C_MDER);
+
temp = readl(lpi2c_imx->base + LPI2C_MCR);
temp |= MCR_MEN;
writel(temp, lpi2c_imx->base + LPI2C_MCR);
@@ -462,6 +484,154 @@ static void lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx,
lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE);
}
+static void lpi2c_dma_unmap(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ struct dma_chan *chan = lpi2c_imx->dma_direction == DMA_FROM_DEVICE
+ ? lpi2c_imx->dma_rx : lpi2c_imx->dma_tx;
+
+ dma_unmap_single(chan->device->dev, lpi2c_imx->dma_addr,
+ lpi2c_imx->dma_len, lpi2c_imx->dma_direction);
+
+ lpi2c_imx->dma_direction = DMA_NONE;
+}
+
+static void lpi2c_cleanup_dma(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ if (lpi2c_imx->dma_direction == DMA_NONE)
+ return;
+ else if (lpi2c_imx->dma_direction == DMA_FROM_DEVICE)
+ dmaengine_terminate_all(lpi2c_imx->dma_rx);
+ else if (lpi2c_imx->dma_direction == DMA_TO_DEVICE)
+ dmaengine_terminate_all(lpi2c_imx->dma_tx);
+
+ lpi2c_dma_unmap(lpi2c_imx);
+}
+
+static void lpi2c_dma_callback(void *data)
+{
+ struct lpi2c_imx_struct *lpi2c_imx = (struct lpi2c_imx_struct *)data;
+
+ lpi2c_dma_unmap(lpi2c_imx);
+ writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
+ lpi2c_imx->xferred = true;
+
+ complete(&lpi2c_imx->complete);
+}
+
+static int lpi2c_dma_submit(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msg)
+{
+ bool read = msg->flags & I2C_M_RD;
+ enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+ struct dma_chan *chan = read ? lpi2c_imx->dma_rx : lpi2c_imx->dma_tx;
+ struct dma_async_tx_descriptor *txdesc;
+ dma_cookie_t cookie;
+
+ lpi2c_imx->dma_len = read ? msg->len - 1 : msg->len;
+ lpi2c_imx->msg = msg;
+ lpi2c_imx->dma_direction = dir;
+
+ if (IS_ERR(chan))
+ return PTR_ERR(chan);
+
+ lpi2c_imx->dma_addr = dma_map_single(chan->device->dev,
+ lpi2c_imx->dma_buf,
+ lpi2c_imx->dma_len, dir);
+ if (dma_mapping_error(chan->device->dev, lpi2c_imx->dma_addr)) {
+ dev_err(&lpi2c_imx->adapter.dev, "dma map failed, use pio\n");
+ return -EINVAL;
+ }
+
+ txdesc = dmaengine_prep_slave_single(chan, lpi2c_imx->dma_addr,
+ lpi2c_imx->dma_len, read ?
+ DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!txdesc) {
+ dev_err(&lpi2c_imx->adapter.dev, "dma prep slave sg failed, use pio\n");
+ lpi2c_cleanup_dma(lpi2c_imx);
+ return -EINVAL;
+ }
+
+ reinit_completion(&lpi2c_imx->complete);
+ txdesc->callback = lpi2c_dma_callback;
+ txdesc->callback_param = (void *)lpi2c_imx;
+
+ cookie = dmaengine_submit(txdesc);
+ if (dma_submit_error(cookie)) {
+ dev_err(&lpi2c_imx->adapter.dev, "submitting dma failed, use pio\n");
+ lpi2c_cleanup_dma(lpi2c_imx);
+ return -EINVAL;
+ }
+
+ lpi2c_imx_intctrl(lpi2c_imx, MIER_NDIE);
+
+ dma_async_issue_pending(chan);
+
+ return 0;
+}
+
+static bool is_use_dma(struct lpi2c_imx_struct *lpi2c_imx, struct i2c_msg *msg)
+{
+ if (!lpi2c_imx->can_use_dma)
+ return false;
+
+ if (msg->len < I2C_DMA_THRESHOLD)
+ return false;
+
+ return true;
+}
+
+static int lpi2c_imx_dma_push_rx_cmd(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msg)
+{
+ unsigned int temp, rx_remain;
+ unsigned long orig_jiffies = jiffies;
+
+ if ((msg->flags & I2C_M_RD)) {
+ rx_remain = msg->len;
+ do {
+ temp = rx_remain > CHUNK_DATA ?
+ CHUNK_DATA - 1 : rx_remain - 1;
+ temp |= (RECV_DATA << 8);
+ while ((readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff) > (lpi2c_imx->rxfifosize >> 1)) {
+ if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(1000))) {
+ dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
+ if (lpi2c_imx->adapter.bus_recovery_info)
+ i2c_recover_bus(&lpi2c_imx->adapter);
+ return -ETIMEDOUT;
+ }
+ schedule();
+ }
+ writel(temp, lpi2c_imx->base + LPI2C_MTDR);
+ rx_remain = rx_remain - (temp & 0xff) - 1;
+ } while (rx_remain > 0);
+ }
+
+ return 0;
+}
+
+static int lpi2c_dma_xfer(struct lpi2c_imx_struct *lpi2c_imx,
+ struct i2c_msg *msg)
+{
+ int result;
+
+ result = lpi2c_dma_submit(lpi2c_imx, msg);
+ if (!result) {
+ result = lpi2c_imx_dma_push_rx_cmd(lpi2c_imx, msg);
+ if (result)
+ return result;
+ result = lpi2c_imx_msg_complete(lpi2c_imx);
+ return result;
+ }
+
+ /* DMA xfer failed, try to use PIO, clean up dma things */
+ i2c_put_dma_safe_msg_buf(lpi2c_imx->dma_buf, lpi2c_imx->msg,
+ lpi2c_imx->xferred);
+ lpi2c_cleanup_dma(lpi2c_imx);
+
+ return DMA_ERR_I2C_USE_PIO;
+}
+
static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
struct i2c_msg *msgs, int num)
{
@@ -474,6 +644,9 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
return result;
for (i = 0; i < num; i++) {
+ lpi2c_imx->xferred = false;
+ lpi2c_imx->using_dma = false;
+
result = lpi2c_imx_start(lpi2c_imx, &msgs[i]);
if (result)
goto disable;
@@ -482,9 +655,24 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
if (num == 1 && msgs[0].len == 0)
goto stop;
+ if (is_use_dma(lpi2c_imx, &msgs[i])) {
+ lpi2c_imx->using_dma = true;
+
+ writel(0x1, lpi2c_imx->base + LPI2C_MFCR);
+
+ lpi2c_imx->dma_buf = i2c_get_dma_safe_msg_buf(&msgs[i],
+ I2C_DMA_THRESHOLD);
+ if (lpi2c_imx->dma_buf) {
+ result = lpi2c_dma_xfer(lpi2c_imx, &msgs[i]);
+ if (result != DMA_ERR_I2C_USE_PIO)
+ goto stop;
+ }
+ }
+
+ lpi2c_imx->using_dma = false;
lpi2c_imx->delivered = 0;
lpi2c_imx->msglen = msgs[i].len;
- init_completion(&lpi2c_imx->complete);
+ reinit_completion(&lpi2c_imx->complete);
if (msgs[i].flags & I2C_M_RD)
lpi2c_imx_read(lpi2c_imx, &msgs[i]);
@@ -503,7 +691,16 @@ static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
}
stop:
- lpi2c_imx_stop(lpi2c_imx);
+ if (!lpi2c_imx->using_dma)
+ lpi2c_imx_stop(lpi2c_imx);
+ else {
+ i2c_put_dma_safe_msg_buf(lpi2c_imx->dma_buf, lpi2c_imx->msg,
+ lpi2c_imx->xferred);
+ if (result) {
+ lpi2c_cleanup_dma(lpi2c_imx);
+ writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
+ }
+ }
temp = readl(lpi2c_imx->base + LPI2C_MSR);
if ((temp & MSR_NDF) && !result)
@@ -528,6 +725,10 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
temp = readl(lpi2c_imx->base + LPI2C_MSR);
if (temp & MSR_NDF) {
+ if (lpi2c_imx->using_dma) {
+ lpi2c_cleanup_dma(lpi2c_imx);
+ writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
+ }
complete(&lpi2c_imx->complete);
goto ret;
}
@@ -623,6 +824,77 @@ static const struct of_device_id lpi2c_imx_of_match[] = {
};
MODULE_DEVICE_TABLE(of, lpi2c_imx_of_match);
+static void lpi2c_dma_exit(struct lpi2c_imx_struct *lpi2c_imx)
+{
+ if (lpi2c_imx->dma_rx) {
+ dma_release_channel(lpi2c_imx->dma_rx);
+ lpi2c_imx->dma_rx = NULL;
+ }
+
+ if (lpi2c_imx->dma_tx) {
+ dma_release_channel(lpi2c_imx->dma_tx);
+ lpi2c_imx->dma_tx = NULL;
+ }
+}
+
+static int lpi2c_dma_init(struct device *dev,
+ struct lpi2c_imx_struct *lpi2c_imx)
+{
+ int ret;
+ struct dma_slave_config dma_sconfig;
+
+ /* Prepare for TX DMA: */
+ lpi2c_imx->dma_tx = dma_request_chan(dev, "tx");
+ if (IS_ERR(lpi2c_imx->dma_tx)) {
+ ret = PTR_ERR(lpi2c_imx->dma_tx);
+ dev_err(dev, "can't get the TX DMA channel, error %d!\n", ret);
+ lpi2c_imx->dma_tx = NULL;
+ goto err;
+ }
+
+ dma_sconfig.dst_addr = lpi2c_imx->phy_addr + LPI2C_MTDR;
+ dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_sconfig.dst_maxburst = 1;
+ dma_sconfig.direction = DMA_MEM_TO_DEV;
+ ret = dmaengine_slave_config(lpi2c_imx->dma_tx, &dma_sconfig);
+ if (ret < 0) {
+ dev_err(dev, "can't configure tx channel (%d)\n", ret);
+ goto fail_tx;
+ }
+
+ /* Prepare for RX DMA: */
+ lpi2c_imx->dma_rx = dma_request_chan(dev, "rx");
+ if (IS_ERR(lpi2c_imx->dma_rx)) {
+ ret = PTR_ERR(lpi2c_imx->dma_rx);
+ dev_err(dev, "can't get the RX DMA channel, error %d\n", ret);
+ lpi2c_imx->dma_rx = NULL;
+ goto fail_tx;
+ }
+
+ dma_sconfig.src_addr = lpi2c_imx->phy_addr + LPI2C_MRDR;
+ dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_sconfig.src_maxburst = 1;
+ dma_sconfig.direction = DMA_DEV_TO_MEM;
+ ret = dmaengine_slave_config(lpi2c_imx->dma_rx, &dma_sconfig);
+ if (ret < 0) {
+ dev_err(dev, "can't configure rx channel (%d)\n", ret);
+ goto fail_rx;
+ }
+
+ lpi2c_imx->can_use_dma = true;
+ lpi2c_imx->using_dma = false;
+
+ return 0;
+fail_rx:
+ dma_release_channel(lpi2c_imx->dma_rx);
+fail_tx:
+ dma_release_channel(lpi2c_imx->dma_tx);
+err:
+ lpi2c_dma_exit(lpi2c_imx);
+ lpi2c_imx->can_use_dma = false;
+ return ret;
+}
+
static int lpi2c_imx_clocks_prepare(struct lpi2c_imx_struct *lpi2c_imx)
{
int ret = 0;
@@ -656,15 +928,18 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
struct lpi2c_imx_struct *lpi2c_imx;
unsigned int temp;
int ret;
+ struct resource *res;
lpi2c_imx = devm_kzalloc(&pdev->dev, sizeof(*lpi2c_imx), GFP_KERNEL);
if (!lpi2c_imx)
return -ENOMEM;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lpi2c_imx->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(lpi2c_imx->base))
return PTR_ERR(lpi2c_imx->base);
+ lpi2c_imx->phy_addr = (dma_addr_t)res->start;
lpi2c_imx->irq = platform_get_irq(pdev, 0);
if (lpi2c_imx->irq < 0)
return lpi2c_imx->irq;
@@ -716,6 +991,17 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
if (ret == -EPROBE_DEFER)
goto rpm_disable;
+ /* Init DMA */
+ lpi2c_imx->dma_direction = DMA_NONE;
+ ret = lpi2c_dma_init(&pdev->dev, lpi2c_imx);
+ if (ret) {
+ dev_err_probe(&pdev->dev, ret, "dma setup error %d, use pio\n", ret);
+ if (ret == -EPROBE_DEFER)
+ goto rpm_disable;
+ }
+
+ init_completion(&lpi2c_imx->complete);
+
ret = i2c_add_adapter(&lpi2c_imx->adapter);
if (ret)
goto rpm_disable;
--
2.25.1
