Unverified Commit 89b35e3f authored by Eddie James's avatar Eddie James Committed by Mark Brown
Browse files

spi: fsi: Implement a timeout for polling status 



The data transfer routines must poll the status register to
determine when more data can be shifted in or out. If the hardware
gets into a bad state, these polling loops may never exit. Prevent
this by returning an error if a timeout is exceeded.

Signed-off-by: default avatarEddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220317211426.38940-1-eajames@linux.ibm.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent ebc4cb43

drivers/spi/spi-fsi.c

+10 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#define SPI_FSI_BASE			0x70000

#define SPI_FSI_INIT_TIMEOUT_MS		1000

#define SPI_FSI_STATUS_TIMEOUT_MS	100

#define SPI_FSI_MAX_RX_SIZE		8

#define SPI_FSI_MAX_TX_SIZE		40
@@ -299,6 +300,7 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx, 
				 struct spi_transfer *transfer)

{

	int rc = 0;

	unsigned long end;

	u64 status = 0ULL;



	if (transfer->tx_buf) {
@@ -315,10 +317,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx, 
			if (rc)

				return rc;



			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);

			do {

				rc = fsi_spi_status(ctx, &status, "TX");

				if (rc)

					return rc;



				if (time_after(jiffies, end))

					return -ETIMEDOUT;

			} while (status & SPI_FSI_STATUS_TDR_FULL);



			sent += nb;
@@ -329,10 +335,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx, 
		u8 *rx = transfer->rx_buf;



		while (transfer->len > recv) {

			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);

			do {

				rc = fsi_spi_status(ctx, &status, "RX");

				if (rc)

					return rc;



				if (time_after(jiffies, end))

					return -ETIMEDOUT;

			} while (!(status & SPI_FSI_STATUS_RDR_FULL));



			rc = fsi_spi_read_reg(ctx, SPI_FSI_DATA_RX, &in);