From: Matthew Gerlach <[email protected]> This patch works around a bug in the SPI Slave to Avalon Master bridge. The SPI slave will send an unexpected extra SOP in the following case.
One in approximately one million read requests results in an apparant stall on the avalon bus where the SPI slave inserts IDLE characters. When the stall is over, the slave sends an extra SOP character instead of the 0x7c indicating channel. The other characters are correct. To eliminate the impact of the bug, this patch changes to look for the last SOP as the start point of the valid phy rx data. Signed-off-by: Matthew Gerlach <[email protected]> Signed-off-by: Xu Yilun <[email protected]> Signed-off-by: Luis Claudio R. Goncalves <[email protected]> Signed-off-by: Tom Rix <[email protected]> --- v2: no change. --- drivers/base/regmap/regmap-spi-avmm.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/base/regmap/regmap-spi-avmm.c b/drivers/base/regmap/regmap-spi-avmm.c index ab329d2..632e018 100644 --- a/drivers/base/regmap/regmap-spi-avmm.c +++ b/drivers/base/regmap/regmap-spi-avmm.c @@ -433,14 +433,14 @@ static int pkt_phy_rx_parse(struct device *dev, { char *b, *p; - b = phy_buf; p = trans_buf; - /* Find the SOP */ - while (b < phy_buf + phy_len && *b != PKT_SOP) - b++; + /* Find the last SOP */ + b = (phy_buf + phy_len) - 1; + while (b >= phy_buf && *b != PKT_SOP) + b--; - if (b >= phy_buf + phy_len) { + if (b < phy_buf) { dev_err(dev, "%s no SOP\n", __func__); return -EINVAL; } -- 2.7.4
