Commit ce3b9338 authored by David Mosberger-Tang's avatar David Mosberger-Tang Committed by Kalle Valo
Browse files

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: default avatarDavid Mosberger-Tang <davidm@egauge.net>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210227172818.1711071-3-davidm@egauge.net
parent 5ee2d9dd

drivers/net/wireless/microchip/wilc1000/spi.c

+61 −1
Original line number Diff line number Diff line
@@ -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);

}



/********************************************