[PATCH v3 3/3] spi: stm32-qspi: add automatic poll status feature

patrice.chotard
2021-05-18T09:42:37Z

From: Patrice Chotard <patrice.chotard@foss.st.com>

STM32 QSPI is able to automatically poll a specified register inside the
memory and relieve the CPU from this task.

As example, when erasing a large memory area, we got cpu load
equal to 50%. This patch allows to perform the same operation
with a cpu load around 2%.

Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
---
Changes in v3:
- Remove spi_mem_finalize_op() API added in v2.

Changes in v2:
- mask and match stm32_qspi_poll_status() parameters are 2-byte wide
- Make usage of new spi_mem_finalize_op() API in stm32_qspi_wait_poll_status()

drivers/spi/spi-stm32-qspi.c | 83 ++++++++++++++++++++++++++++++++----
1 file changed, 75 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 7e640ccc7e77..01168a859005 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -36,6 +36,7 @@
#define CR_FTIE BIT(18)
#define CR_SMIE BIT(19)
#define CR_TOIE BIT(20)
+#define CR_APMS BIT(22)
#define CR_PRESC_MASK GENMASK(31, 24)

#define QSPI_DCR 0x04
@@ -53,6 +54,7 @@
#define QSPI_FCR 0x0c
#define FCR_CTEF BIT(0)
#define FCR_CTCF BIT(1)
+#define FCR_CSMF BIT(3)

#define QSPI_DLR 0x10

@@ -107,6 +109,7 @@ struct stm32_qspi {
u32 clk_rate;
struct stm32_qspi_flash flash[STM32_QSPI_MAX_NORCHIP];
struct completion data_completion;
+ struct completion match_completion;
u32 fmode;

struct dma_chan *dma_chtx;
@@ -115,6 +118,7 @@ struct stm32_qspi {

u32 cr_reg;
u32 dcr_reg;
+ unsigned long status_timeout;

/*
* to protect device configuration, could be different between
@@ -128,11 +132,20 @@ static irqreturn_t stm32_qspi_irq(int irq, void *dev_id)
struct stm32_qspi *qspi = (struct stm32_qspi *)dev_id;
u32 cr, sr;

+ cr = readl_relaxed(qspi->io_base + QSPI_CR);
sr = readl_relaxed(qspi->io_base + QSPI_SR);

+ if (cr & CR_SMIE && sr & SR_SMF) {
+ /* disable irq */
+ cr &= ~CR_SMIE;
+ writel_relaxed(cr, qspi->io_base + QSPI_CR);
+ complete(&qspi->match_completion);
+
+ return IRQ_HANDLED;
+ }
+
if (sr & (SR_TEF | SR_TCF)) {
/* disable irq */
- cr = readl_relaxed(qspi->io_base + QSPI_CR);
cr &= ~CR_TCIE & ~CR_TEIE;
writel_relaxed(cr, qspi->io_base + QSPI_CR);
complete(&qspi->data_completion);
@@ -319,6 +332,24 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
return err;
}

+static int stm32_qspi_wait_poll_status(struct stm32_qspi *qspi,
+ const struct spi_mem_op *op)
+{
+ u32 cr;
+
+ reinit_completion(&qspi->match_completion);
+ cr = readl_relaxed(qspi->io_base + QSPI_CR);
+ writel_relaxed(cr | CR_SMIE, qspi->io_base + QSPI_CR);
+
+ if (!wait_for_completion_timeout(&qspi->match_completion,
+ msecs_to_jiffies(qspi->status_timeout)))
+ return -ETIMEDOUT;
+
+ writel_relaxed(FCR_CSMF, qspi->io_base + QSPI_FCR);
+
+ return 0;
+}
+
static int stm32_qspi_get_mode(struct stm32_qspi *qspi, u8 buswidth)
{
if (buswidth == 4)
@@ -332,7 +363,7 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
struct stm32_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
struct stm32_qspi_flash *flash = &qspi->flash[mem->spi->chip_select];
u32 ccr, cr;
- int timeout, err = 0;
+ int timeout, err = 0, err_poll_status = 0;

dev_dbg(qspi->dev, "cmd:%#x mode:%d.%d.%d.%d addr:%#llx len:%#x\n",
op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
@@ -378,6 +409,9 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
if (op->addr.nbytes && qspi->fmode != CCR_FMODE_MM)
writel_relaxed(op->addr.val, qspi->io_base + QSPI_AR);

+ if (qspi->fmode == CCR_FMODE_APM)
+ err_poll_status = stm32_qspi_wait_poll_status(qspi, op);
+
err = stm32_qspi_tx(qspi, op);

/*
@@ -387,7 +421,7 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
* byte of device (device size - fifo size). like device size is not
* knows, the prefetching is always stop.
*/
- if (err || qspi->fmode == CCR_FMODE_MM)
+ if (err || err_poll_status || qspi->fmode == CCR_FMODE_MM)
goto abort;

/* wait end of tx in indirect mode */
@@ -406,15 +440,46 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
cr, !(cr & CR_ABORT), 1,
STM32_ABT_TIMEOUT_US);

- writel_relaxed(FCR_CTCF, qspi->io_base + QSPI_FCR);
+ writel_relaxed(FCR_CTCF | FCR_CSMF, qspi->io_base + QSPI_FCR);

- if (err || timeout)
- dev_err(qspi->dev, "%s err:%d abort timeout:%d\n",
- __func__, err, timeout);
+ if (err || err_poll_status || timeout)
+ dev_err(qspi->dev, "%s err:%d err_poll_status:%d abort timeout:%d\n",
+ __func__, err, err_poll_status, timeout);

return err;
}

+static int stm32_qspi_poll_status(struct spi_mem *mem, const struct spi_mem_op *op,
+ u16 mask, u16 match,
+ unsigned long initial_delay_us,
+ unsigned long polling_rate_us,
+ unsigned long timeout_ms)
+{
+ struct stm32_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
+ int ret;
+
+ ret = pm_runtime_get_sync(qspi->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(qspi->dev);
+ return ret;
+ }
+
+ mutex_lock(&qspi->lock);
+
+ writel_relaxed(mask, qspi->io_base + QSPI_PSMKR);
+ writel_relaxed(match, qspi->io_base + QSPI_PSMAR);
+ qspi->fmode = CCR_FMODE_APM;
+ qspi->status_timeout = timeout_ms;
+
+ ret = stm32_qspi_send(mem, op);
+ mutex_unlock(&qspi->lock);
+
+ pm_runtime_mark_last_busy(qspi->dev);
+ pm_runtime_put_autosuspend(qspi->dev);
+
+ return ret;
+}
+
static int stm32_qspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct stm32_qspi *qspi = spi_controller_get_devdata(mem->spi->master);
@@ -527,7 +592,7 @@ static int stm32_qspi_setup(struct spi_device *spi)
flash->presc = presc;

mutex_lock(&qspi->lock);
- qspi->cr_reg = 3 << CR_FTHRES_SHIFT | CR_SSHIFT | CR_EN;
+ qspi->cr_reg = CR_APMS | 3 << CR_FTHRES_SHIFT | CR_SSHIFT | CR_EN;
writel_relaxed(qspi->cr_reg, qspi->io_base + QSPI_CR);

/* set dcr fsize to max address */
@@ -607,6 +672,7 @@ static const struct spi_controller_mem_ops stm32_qspi_mem_ops = {
.exec_op = stm32_qspi_exec_op,
.dirmap_create = stm32_qspi_dirmap_create,
.dirmap_read = stm32_qspi_dirmap_read,
+ .poll_status = stm32_qspi_poll_status,
};

static int stm32_qspi_probe(struct platform_device *pdev)
@@ -661,6 +727,7 @@ static int stm32_qspi_probe(struct platform_device *pdev)
}

init_completion(&qspi->data_completion);
+ init_completion(&qspi->match_completion);

qspi->clk = devm_clk_get(dev, NULL);
if (IS_ERR(qspi->clk)) {
--
2.17.1