From 6fd6fd68c9e2f3a206a098ef57b1d5548f9d00d1 Mon Sep 17 00:00:00 2001 From: Zachary Zhang Date: Wed, 13 Sep 2017 18:21:39 +0200 Subject: [PATCH] spi: armada-3700: Fix padding when sending not 4-byte aligned data In 4-byte transfer mode, extra padding/dummy bytes '0xff' would be sent in write operation if TX data is not 4-byte aligned since the SPI data register is always shifted out as whole 4 bytes. Fix this by using the header count feature that allows to transfer 0 to 4 bytes. Use it to actually send the first 1 to 3 bytes of data before the rest of the buffer that will hence be 4-byte aligned. Signed-off-by: Zachary Zhang Signed-off-by: Miquel Raynal Signed-off-by: Mark Brown --- drivers/spi/spi-armada-3700.c | 135 +++++++++++----------------------- 1 file changed, 41 insertions(+), 94 deletions(-) diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c index a28702b1fa05..9172cb2d2e7a 100644 --- a/drivers/spi/spi-armada-3700.c +++ b/drivers/spi/spi-armada-3700.c @@ -99,11 +99,6 @@ /* A3700_SPI_IF_TIME_REG */ #define A3700_SPI_CLK_CAPT_EDGE BIT(7) -/* Flags and macros for struct a3700_spi */ -#define A3700_INSTR_CNT 1 -#define A3700_ADDR_CNT 3 -#define A3700_DUMMY_CNT 1 - struct a3700_spi { struct spi_master *master; void __iomem *base; @@ -117,9 +112,6 @@ struct a3700_spi { u8 byte_len; u32 wait_mask; struct completion done; - u32 addr_cnt; - u32 instr_cnt; - size_t hdr_cnt; }; static u32 spireg_read(struct a3700_spi *a3700_spi, u32 offset) @@ -449,59 +441,43 @@ static void a3700_spi_set_cs(struct spi_device *spi, bool enable) static void a3700_spi_header_set(struct a3700_spi *a3700_spi) { - u32 instr_cnt = 0, addr_cnt = 0, dummy_cnt = 0; + unsigned int addr_cnt; u32 val = 0; /* Clear the header registers */ spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, 0); spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, 0); spireg_write(a3700_spi, A3700_SPI_IF_RMODE_REG, 0); + spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, 0); /* Set header counters */ if (a3700_spi->tx_buf) { - if (a3700_spi->buf_len <= a3700_spi->instr_cnt) { - instr_cnt = a3700_spi->buf_len; - } else if (a3700_spi->buf_len <= (a3700_spi->instr_cnt + - a3700_spi->addr_cnt)) { - instr_cnt = a3700_spi->instr_cnt; - addr_cnt = a3700_spi->buf_len - instr_cnt; - } else if (a3700_spi->buf_len <= a3700_spi->hdr_cnt) { - instr_cnt = a3700_spi->instr_cnt; - addr_cnt = a3700_spi->addr_cnt; - /* Need to handle the normal write case with 1 byte - * data - */ - if (!a3700_spi->tx_buf[instr_cnt + addr_cnt]) - dummy_cnt = a3700_spi->buf_len - instr_cnt - - addr_cnt; + /* + * when tx data is not 4 bytes aligned, there will be unexpected + * bytes out of SPI output register, since it always shifts out + * as whole 4 bytes. This might cause incorrect transaction with + * some devices. To avoid that, use SPI header count feature to + * transfer up to 3 bytes of data first, and then make the rest + * of data 4-byte aligned. + */ + addr_cnt = a3700_spi->buf_len % 4; + if (addr_cnt) { + val = (addr_cnt & A3700_SPI_ADDR_CNT_MASK) + << A3700_SPI_ADDR_CNT_BIT; + spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val); + + /* Update the buffer length to be transferred */ + a3700_spi->buf_len -= addr_cnt; + + /* transfer 1~3 bytes through address count */ + val = 0; + while (addr_cnt--) { + val = (val << 8) | a3700_spi->tx_buf[0]; + a3700_spi->tx_buf++; + } + spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val); } - val |= ((instr_cnt & A3700_SPI_INSTR_CNT_MASK) - << A3700_SPI_INSTR_CNT_BIT); - val |= ((addr_cnt & A3700_SPI_ADDR_CNT_MASK) - << A3700_SPI_ADDR_CNT_BIT); - val |= ((dummy_cnt & A3700_SPI_DUMMY_CNT_MASK) - << A3700_SPI_DUMMY_CNT_BIT); } - spireg_write(a3700_spi, A3700_SPI_IF_HDR_CNT_REG, val); - - /* Update the buffer length to be transferred */ - a3700_spi->buf_len -= (instr_cnt + addr_cnt + dummy_cnt); - - /* Set Instruction */ - val = 0; - while (instr_cnt--) { - val = (val << 8) | a3700_spi->tx_buf[0]; - a3700_spi->tx_buf++; - } - spireg_write(a3700_spi, A3700_SPI_IF_INST_REG, val); - - /* Set Address */ - val = 0; - while (addr_cnt--) { - val = (val << 8) | a3700_spi->tx_buf[0]; - a3700_spi->tx_buf++; - } - spireg_write(a3700_spi, A3700_SPI_IF_ADDR_REG, val); } static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi) @@ -515,35 +491,12 @@ static int a3700_is_wfifo_full(struct a3700_spi *a3700_spi) static int a3700_spi_fifo_write(struct a3700_spi *a3700_spi) { u32 val; - int i = 0; while (!a3700_is_wfifo_full(a3700_spi) && a3700_spi->buf_len) { - val = 0; - if (a3700_spi->buf_len >= 4) { - val = cpu_to_le32(*(u32 *)a3700_spi->tx_buf); - spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val); - - a3700_spi->buf_len -= 4; - a3700_spi->tx_buf += 4; - } else { - /* - * If the remained buffer length is less than 4-bytes, - * we should pad the write buffer with all ones. So that - * it avoids overwrite the unexpected bytes following - * the last one. - */ - val = GENMASK(31, 0); - while (a3700_spi->buf_len) { - val &= ~(0xff << (8 * i)); - val |= *a3700_spi->tx_buf++ << (8 * i); - i++; - a3700_spi->buf_len--; - - spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, - val); - } - break; - } + val = cpu_to_le32(*(u32 *)a3700_spi->tx_buf); + spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, val); + a3700_spi->buf_len -= 4; + a3700_spi->tx_buf += 4; } return 0; @@ -648,9 +601,6 @@ static int a3700_spi_transfer_one(struct spi_master *master, a3700_spi->rx_buf = xfer->rx_buf; a3700_spi->buf_len = xfer->len; - /* SPI transfer headers */ - a3700_spi_header_set(a3700_spi); - if (xfer->tx_buf) nbits = xfer->tx_nbits; else if (xfer->rx_buf) @@ -658,6 +608,12 @@ static int a3700_spi_transfer_one(struct spi_master *master, a3700_spi_pin_mode_set(a3700_spi, nbits, xfer->rx_buf ? true : false); + /* Flush the FIFOs */ + a3700_spi_fifo_flush(a3700_spi); + + /* Transfer first bytes of data when buffer is not 4-byte aligned */ + a3700_spi_header_set(a3700_spi); + if (xfer->rx_buf) { /* Set read data length */ spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, @@ -736,16 +692,11 @@ static int a3700_spi_transfer_one(struct spi_master *master, dev_err(&spi->dev, "wait wfifo empty timed out\n"); return -ETIMEDOUT; } - } else { - /* - * If the instruction in SPI_INSTR does not require data - * to be written to the SPI device, wait until SPI_RDY - * is 1 for the SPI interface to be in idle. - */ - if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) { - dev_err(&spi->dev, "wait xfer ready timed out\n"); - return -ETIMEDOUT; - } + } + + if (!a3700_spi_transfer_wait(spi, A3700_SPI_XFER_RDY)) { + dev_err(&spi->dev, "wait xfer ready timed out\n"); + return -ETIMEDOUT; } val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG); @@ -837,10 +788,6 @@ static int a3700_spi_probe(struct platform_device *pdev) memset(spi, 0, sizeof(struct a3700_spi)); spi->master = master; - spi->instr_cnt = A3700_INSTR_CNT; - spi->addr_cnt = A3700_ADDR_CNT; - spi->hdr_cnt = A3700_INSTR_CNT + A3700_ADDR_CNT + - A3700_DUMMY_CNT; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); spi->base = devm_ioremap_resource(dev, res);