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authorArnd Bergmann <arnd@arndb.de>2016-11-08 14:46:12 +0100
committerMark Brown <broonie@kernel.org>2016-11-09 13:05:19 +0000
commitdb30083813b559e98e10ae26bd09d3dc69be7fb7 (patch)
treebeaa5957b74b8fd9ae82a4afe74dc9414c919394 /drivers/spi/spi-rspi.c
parent3be09bec42a800d4f8ead8119c462f3eb4fad435 (diff)
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spi: rspi: avoid uninitialized variable access
The newly introduced rspi_pio_transfer_in_or_our() function must take either a valid 'rx' or 'tx' pointer, and has undefined behavior if both are NULL, as found by 'gcc -Wmaybe-unintialized': drivers/spi/spi-rspi.c: In function 'rspi_pio_transfer_in_or_our': drivers/spi/spi-rspi.c:558:5: error: 'len' may be used uninitialized in this function [-Werror=maybe-uninitialized] The analysis of the function is correct in principle, but the code is currently safe because both callers always pass exactly one of the two pointers. Looking closer at this function shows that having a combined method for rx and tx here actually increases the complexity and the size of the file. This simplifies it again by keeping the two separate, which then ends up avoiding that warning. Fixes: 3be09bec42a8 ("spi: rspi: supports 32bytes buffer for DUAL and QUAD") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-rspi.c')
-rw-r--r--drivers/spi/spi-rspi.c94
1 files changed, 45 insertions, 49 deletions
diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 3bab75ab1b25..9daf50031737 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -515,51 +515,6 @@ static int rspi_pio_transfer(struct rspi_data *rspi, const u8 *tx, u8 *rx,
return 0;
}
-static int rspi_pio_transfer_in_or_our(struct rspi_data *rspi, const u8 *tx,
- u8 *rx, unsigned int n)
-{
- unsigned int i, len;
- int ret;
-
- while (n > 0) {
- if (tx) {
- len = qspi_set_send_trigger(rspi, n);
- if (len == QSPI_BUFFER_SIZE) {
- ret = rspi_wait_for_tx_empty(rspi);
- if (ret < 0) {
- dev_err(&rspi->master->dev, "transmit timeout\n");
- return ret;
- }
- for (i = 0; i < len; i++)
- rspi_write_data(rspi, *tx++);
- } else {
- ret = rspi_pio_transfer(rspi, tx, NULL, n);
- if (ret < 0)
- return ret;
- }
- }
- if (rx) {
- len = qspi_set_receive_trigger(rspi, n);
- if (len == QSPI_BUFFER_SIZE) {
- ret = rspi_wait_for_rx_full(rspi);
- if (ret < 0) {
- dev_err(&rspi->master->dev, "receive timeout\n");
- return ret;
- }
- for (i = 0; i < len; i++)
- *rx++ = rspi_read_data(rspi);
- } else {
- ret = rspi_pio_transfer(rspi, NULL, rx, n);
- if (ret < 0)
- return ret;
- *rx++ = ret;
- }
- }
- n -= len;
- }
- return 0;
-}
-
static void rspi_dma_complete(void *arg)
{
struct rspi_data *rspi = arg;
@@ -831,6 +786,9 @@ static int qspi_transfer_out_in(struct rspi_data *rspi,
static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
{
+ const u8 *tx = xfer->tx_buf;
+ unsigned int n = xfer->len;
+ unsigned int i, len;
int ret;
if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer)) {
@@ -839,9 +797,23 @@ static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
return ret;
}
- ret = rspi_pio_transfer_in_or_our(rspi, xfer->tx_buf, NULL, xfer->len);
- if (ret < 0)
- return ret;
+ while (n > 0) {
+ len = qspi_set_send_trigger(rspi, n);
+ if (len == QSPI_BUFFER_SIZE) {
+ ret = rspi_wait_for_tx_empty(rspi);
+ if (ret < 0) {
+ dev_err(&rspi->master->dev, "transmit timeout\n");
+ return ret;
+ }
+ for (i = 0; i < len; i++)
+ rspi_write_data(rspi, *tx++);
+ } else {
+ ret = rspi_pio_transfer(rspi, tx, NULL, n);
+ if (ret < 0)
+ return ret;
+ }
+ n -= len;
+ }
/* Wait for the last transmission */
rspi_wait_for_tx_empty(rspi);
@@ -851,13 +823,37 @@ static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
static int qspi_transfer_in(struct rspi_data *rspi, struct spi_transfer *xfer)
{
+ u8 *rx = xfer->rx_buf;
+ unsigned int n = xfer->len;
+ unsigned int i, len;
+ int ret;
+
if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer)) {
int ret = rspi_dma_transfer(rspi, NULL, &xfer->rx_sg);
if (ret != -EAGAIN)
return ret;
}
- return rspi_pio_transfer_in_or_our(rspi, NULL, xfer->rx_buf, xfer->len);
+ while (n > 0) {
+ len = qspi_set_receive_trigger(rspi, n);
+ if (len == QSPI_BUFFER_SIZE) {
+ ret = rspi_wait_for_rx_full(rspi);
+ if (ret < 0) {
+ dev_err(&rspi->master->dev, "receive timeout\n");
+ return ret;
+ }
+ for (i = 0; i < len; i++)
+ *rx++ = rspi_read_data(rspi);
+ } else {
+ ret = rspi_pio_transfer(rspi, NULL, rx, n);
+ if (ret < 0)
+ return ret;
+ *rx++ = ret;
+ }
+ n -= len;
+ }
+
+ return 0;
}
static int qspi_transfer_one(struct spi_master *master, struct spi_device *spi,