spi: cadence-quadspi: Fix random issues with Xilinx

Merge series from Sai Krishna Potthuri <[email protected]>:

Update Xilinx Versal external DMA read logic to fix random issues
- Instead of having the fixed timeout, update the read timeout based on
the length of the transfer to avoid timeout for larger data size.
- While switching between external DMA read and indirect read, disable the
SPI before configuration and enable it after configuration as recommended
by Octal-SPI Flash Controller specification.

Sai Krishna Potthuri (2):
  spi: cadence-quadspi: Update the read timeout based on the length
  spi: cadence-quadspi: Disable the SPI before reconfiguring

 drivers/spi/spi-cadence-quadspi.c | 40 ++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 16 deletions(-)

--
2.25.1

Author: broonie

drivers/spi/spi-cadence-quadspi.c

@@ -791,6 +791,21 @@ static int cqspi_indirect_read_execute(struct cqspi_flash_pdata *f_pdata,
 	return ret;
 }
 
+static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
+{
+	void __iomem *reg_base = cqspi->iobase;
+	unsigned int reg;
+
+	reg = readl(reg_base + CQSPI_REG_CONFIG);
+
+	if (enable)
+		reg |= CQSPI_REG_CONFIG_ENABLE_MASK;
+	else
+		reg &= ~CQSPI_REG_CONFIG_ENABLE_MASK;
+
+	writel(reg, reg_base + CQSPI_REG_CONFIG);
+}
+
 static int cqspi_versal_indirect_read_dma(struct cqspi_flash_pdata *f_pdata,
 					  u_char *rxbuf, loff_t from_addr,
 					  size_t n_rx)
@@ -815,10 +830,14 @@ static int cqspi_versal_indirect_read_dma(struct cqspi_flash_pdata *f_pdata,
 	if (ret)
 		return ret;
 
+	cqspi_controller_enable(cqspi, 0);
+
 	reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
 	reg |= CQSPI_REG_CONFIG_DMA_MASK;
 	writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
 
+	cqspi_controller_enable(cqspi, 1);
+
 	dma_addr = dma_map_single(dev, rxbuf, bytes_to_dma, DMA_FROM_DEVICE);
 	if (dma_mapping_error(dev, dma_addr)) {
 		dev_err(dev, "dma mapping failed\n");
@@ -863,7 +882,7 @@ static int cqspi_versal_indirect_read_dma(struct cqspi_flash_pdata *f_pdata,
 	reinit_completion(&cqspi->transfer_complete);
 
 	if (!wait_for_completion_timeout(&cqspi->transfer_complete,
-					 msecs_to_jiffies(CQSPI_READ_TIMEOUT_MS))) {
+					 msecs_to_jiffies(max_t(size_t, bytes_to_dma, 500)))) {
 		ret = -ETIMEDOUT;
 		goto failrd;
 	}
@@ -876,10 +895,14 @@ static int cqspi_versal_indirect_read_dma(struct cqspi_flash_pdata *f_pdata,
 	       cqspi->iobase + CQSPI_REG_INDIRECTRD);
 	dma_unmap_single(dev, dma_addr, bytes_to_dma, DMA_FROM_DEVICE);
 
+	cqspi_controller_enable(cqspi, 0);
+
 	reg = readl(cqspi->iobase + CQSPI_REG_CONFIG);
 	reg &= ~CQSPI_REG_CONFIG_DMA_MASK;
 	writel(reg, cqspi->iobase + CQSPI_REG_CONFIG);
 
+	cqspi_controller_enable(cqspi, 1);
+
 	ret = zynqmp_pm_ospi_mux_select(cqspi->pd_dev_id,
 					PM_OSPI_MUX_SEL_LINEAR);
 	if (ret)
@@ -1182,21 +1205,6 @@ static void cqspi_readdata_capture(struct cqspi_st *cqspi,
 	writel(reg, reg_base + CQSPI_REG_READCAPTURE);
 }
 
-static void cqspi_controller_enable(struct cqspi_st *cqspi, bool enable)
-{
-	void __iomem *reg_base = cqspi->iobase;
-	unsigned int reg;
-
-	reg = readl(reg_base + CQSPI_REG_CONFIG);
-
-	if (enable)
-		reg |= CQSPI_REG_CONFIG_ENABLE_MASK;
-	else
-		reg &= ~CQSPI_REG_CONFIG_ENABLE_MASK;
-
-	writel(reg, reg_base + CQSPI_REG_CONFIG);
-}
-
 static void cqspi_configure(struct cqspi_flash_pdata *f_pdata,
 			    unsigned long sclk)
 {