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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: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20220317211426.38940-1-eajames@linux.ibm.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Eddie James 2022-03-17 16:14:26 -05:00 committed by Mark Brown
parent ebc4cb43ea
commit 89b35e3f28
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GPG Key ID: 24D68B725D5487D0
1 changed files with 10 additions and 0 deletions
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10
drivers/spi/spi-fsi.c
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@ -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);