From ce3b933832b6286d181c30f646449d6ccc2a2c8c Mon Sep 17 00:00:00 2001 From: David Mosberger-Tang Date: Sat, 27 Feb 2021 17:29:46 +0000 Subject: wilc1000: Check for errors at end of DMA write 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 Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20210227172818.1711071-3-davidm@egauge.net --- drivers/net/wireless/microchip/wilc1000/spi.c | 62 ++++++++++++++++++++++++++- 1 file changed, 61 insertions(+), 1 deletion(-) (limited to 'drivers/net/wireless/microchip') diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c index fca34d1999ec..0be93eabad69 100644 --- a/drivers/net/wireless/microchip/wilc1000/spi.c +++ b/drivers/net/wireless/microchip/wilc1000/spi.c @@ -47,6 +47,17 @@ static const struct wilc_hif_func wilc_hif_spi; #define SPI_ENABLE_VMM_RETRY_LIMIT 2 +/* SPI response fields (section 11.1.2 in ATWILC1000 User Guide): */ +#define RSP_START_FIELD GENMASK(7, 4) +#define RSP_TYPE_FIELD GENMASK(3, 0) + +/* SPI response values for the response fields: */ +#define RSP_START_TAG 0xc +#define RSP_TYPE_FIRST_PACKET 0x1 +#define RSP_TYPE_INNER_PACKET 0x2 +#define RSP_TYPE_LAST_PACKET 0x3 +#define RSP_STATE_NO_ERROR 0x00 + #define PROTOCOL_REG_PKT_SZ_MASK GENMASK(6, 4) #define PROTOCOL_REG_CRC16_MASK GENMASK(3, 3) #define PROTOCOL_REG_CRC7_MASK GENMASK(2, 2) @@ -750,6 +761,52 @@ 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 (FIELD_GET(RSP_START_FIELD, rsp[i]) == RSP_START_TAG) + 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 (FIELD_GET(RSP_TYPE_FIELD, rsp[i]) != RSP_TYPE_LAST_PACKET + || rsp[i + 1] != RSP_STATE_NO_ERROR) { + 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 +834,10 @@ 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); } /******************************************** -- cgit