After a DMA write to the WILC chip, check for and report any errors.
This is based on code from the wilc driver in the linux-at91
repository.
Signed-off-by: David Mosberger-Tang <davidm@xxxxxxxxxx>
---
drivers/net/wireless/microchip/wilc1000/spi.c | 50 ++++++++++++++++++-
1 file changed, 49 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index fca34d1999ec..b0e096a03a28 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -750,6 +750,51 @@ static int wilc_spi_write_reg(struct wilc *wilc, u32 addr, u32 data)
return 0;
}
+static int spi_data_rsp(struct wilc *wilc, u8 cmd)
+{
+ struct spi_device *spi = to_spi_device(wilc->dev);
+ int result, i;
+ u8 rsp[4];
+
+ /*
+ * The response to data packets is two bytes long. For
+ * efficiency's sake, wilc_spi_write() wisely ignores the
+ * responses for all packets but the final one. The downside
+ * of that optimization is that when the final data packet is
+ * short, we may receive (part of) the response to the
+ * second-to-last packet before the one for the final packet.
+ * To handle this, we always read 4 bytes and then search for
+ * the last byte that contains the "Response Start" code (0xc
+ * in the top 4 bits). We then know that this byte is the
+ * first response byte of the final data packet.
+ */
+ result = wilc_spi_rx(wilc, rsp, sizeof(rsp));
+ if (result) {
+ dev_err(&spi->dev, "Failed bus error...\n");
+ return result;
+ }
+
+ for (i = sizeof(rsp) - 2; i >= 0; --i)
+ if ((rsp[i] & 0xf0) == 0xc0)
+ break;
+
+ if (i < 0) {
+ dev_err(&spi->dev,
+ "Data packet response missing (%02x %02x %02x %02x)\n",
+ rsp[0], rsp[1], rsp[2], rsp[3]);
+ return -1;
+ }
+
+ /* rsp[i] is the last response start byte */
+
+ if (rsp[i] != 0xc3 || rsp[i + 1] != 0x00) {
+ dev_err(&spi->dev, "Data response error (%02x %02x)\n",
+ rsp[i], rsp[i + 1]);
+ return -1;
+ }
+ return 0;
+}
+
static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
{
struct spi_device *spi = to_spi_device(wilc->dev);
@@ -777,7 +822,10 @@ static int wilc_spi_write(struct wilc *wilc, u32 addr, u8 *buf, u32 size)
return result;
}
- return 0;
+ /*
+ * Data response
+ */
+ return spi_data_rsp(wilc, CMD_DMA_EXT_WRITE);
}
/********************************************
--
2.25.1
