Skip to content

Commit

Permalink
spi/sirf: fix the misunderstanding about len of spi_transfer
Browse files Browse the repository at this point in the history 
the unit of len of spi_transfer is in bytes, not in spi words. the
old codes misunderstood that and thought the len is the amount of
spi words. but it is actually how many bytes existing in the spi
buffer.

this patch fixes that and also rename left_tx_cnt and left_rx_cnt
to left_tx_word and left_rx_word to highlight they are in words.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
  • Loading branch information
Qipan Li authored and Mark Brown committed Aug 26, 2013
1 parent 6cca9e2 commit 692fb0f
Showing 1 changed file with 24 additions and 23 deletions.
47 changes: 24 additions & 23 deletions drivers/spi/spi-sirf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -130,8 +130,7 @@

#define ALIGNED(x) (!((u32)x & 0x3))
#define IS_DMA_VALID(x) (x && ALIGNED(x->tx_buf) && ALIGNED(x->rx_buf) && \
ALIGNED(x->len * sspi->word_width) && (x->len * sspi->word_width < \
2 * PAGE_SIZE))
ALIGNED(x->len) && (x->len < 2 * PAGE_SIZE))

struct sirfsoc_spi {
struct spi_bitbang bitbang;
Expand All @@ -152,8 +151,8 @@ struct sirfsoc_spi {
void (*tx_word) (struct sirfsoc_spi *);

/* number of words left to be tranmitted/received */
unsigned int left_tx_cnt;
unsigned int left_rx_cnt;
unsigned int left_tx_word;
unsigned int left_rx_word;

/* rx & tx DMA channels */
struct dma_chan *rx_chan;
Expand All @@ -178,7 +177,7 @@ static void spi_sirfsoc_rx_word_u8(struct sirfsoc_spi *sspi)
sspi->rx = rx;
}

sspi->left_rx_cnt--;
sspi->left_rx_word--;
}

static void spi_sirfsoc_tx_word_u8(struct sirfsoc_spi *sspi)
Expand All @@ -192,7 +191,7 @@ static void spi_sirfsoc_tx_word_u8(struct sirfsoc_spi *sspi)
}

writel(data, sspi->base + SIRFSOC_SPI_TXFIFO_DATA);
sspi->left_tx_cnt--;
sspi->left_tx_word--;
}

static void spi_sirfsoc_rx_word_u16(struct sirfsoc_spi *sspi)
Expand All @@ -207,7 +206,7 @@ static void spi_sirfsoc_rx_word_u16(struct sirfsoc_spi *sspi)
sspi->rx = rx;
}

sspi->left_rx_cnt--;
sspi->left_rx_word--;
}

static void spi_sirfsoc_tx_word_u16(struct sirfsoc_spi *sspi)
Expand All @@ -221,7 +220,7 @@ static void spi_sirfsoc_tx_word_u16(struct sirfsoc_spi *sspi)
}

writel(data, sspi->base + SIRFSOC_SPI_TXFIFO_DATA);
sspi->left_tx_cnt--;
sspi->left_tx_word--;
}

static void spi_sirfsoc_rx_word_u32(struct sirfsoc_spi *sspi)
Expand All @@ -236,7 +235,7 @@ static void spi_sirfsoc_rx_word_u32(struct sirfsoc_spi *sspi)
sspi->rx = rx;
}

sspi->left_rx_cnt--;
sspi->left_rx_word--;

}

Expand All @@ -251,7 +250,7 @@ static void spi_sirfsoc_tx_word_u32(struct sirfsoc_spi *sspi)
}

writel(data, sspi->base + SIRFSOC_SPI_TXFIFO_DATA);
sspi->left_tx_cnt--;
sspi->left_tx_word--;
}

static irqreturn_t spi_sirfsoc_irq(int irq, void *dev_id)
Expand All @@ -272,18 +271,18 @@ static irqreturn_t spi_sirfsoc_irq(int irq, void *dev_id)
| SIRFSOC_SPI_RXFIFO_THD_REACH))
while (!((readl(sspi->base + SIRFSOC_SPI_RXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_EMPTY)) &&
sspi->left_rx_cnt)
sspi->left_rx_word)
sspi->rx_word(sspi);

if (spi_stat & (SIRFSOC_SPI_FIFO_EMPTY
| SIRFSOC_SPI_TXFIFO_THD_REACH))
while (!((readl(sspi->base + SIRFSOC_SPI_TXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_FULL)) &&
sspi->left_tx_cnt)
sspi->left_tx_word)
sspi->tx_word(sspi);

/* Received all words */
if ((sspi->left_rx_cnt == 0) && (sspi->left_tx_cnt == 0)) {
if ((sspi->left_rx_word == 0) && (sspi->left_tx_word == 0)) {
complete(&sspi->rx_done);
writel(0x0, sspi->base + SIRFSOC_SPI_INT_EN);
}
Expand All @@ -305,25 +304,28 @@ static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)

sspi->tx = t->tx_buf ? t->tx_buf : sspi->dummypage;
sspi->rx = t->rx_buf ? t->rx_buf : sspi->dummypage;
sspi->left_tx_cnt = sspi->left_rx_cnt = t->len;
sspi->left_tx_word = sspi->left_rx_word = t->len / sspi->word_width;
INIT_COMPLETION(sspi->rx_done);
INIT_COMPLETION(sspi->tx_done);

writel(SIRFSOC_SPI_INT_MASK_ALL, sspi->base + SIRFSOC_SPI_INT_STATUS);

if (t->len == 1) {
if (sspi->left_tx_word == 1) {
writel(readl(sspi->base + SIRFSOC_SPI_CTRL) |
SIRFSOC_SPI_ENA_AUTO_CLR,
sspi->base + SIRFSOC_SPI_CTRL);
writel(0, sspi->base + SIRFSOC_SPI_TX_DMA_IO_LEN);
writel(0, sspi->base + SIRFSOC_SPI_RX_DMA_IO_LEN);
} else if ((t->len > 1) && (t->len < SIRFSOC_SPI_DAT_FRM_LEN_MAX)) {
} else if ((sspi->left_tx_word > 1) && (sspi->left_tx_word <
SIRFSOC_SPI_DAT_FRM_LEN_MAX)) {
writel(readl(sspi->base + SIRFSOC_SPI_CTRL) |
SIRFSOC_SPI_MUL_DAT_MODE |
SIRFSOC_SPI_ENA_AUTO_CLR,
sspi->base + SIRFSOC_SPI_CTRL);
writel(t->len - 1, sspi->base + SIRFSOC_SPI_TX_DMA_IO_LEN);
writel(t->len - 1, sspi->base + SIRFSOC_SPI_RX_DMA_IO_LEN);
writel(sspi->left_tx_word - 1,
sspi->base + SIRFSOC_SPI_TX_DMA_IO_LEN);
writel(sspi->left_tx_word - 1,
sspi->base + SIRFSOC_SPI_RX_DMA_IO_LEN);
} else {
writel(readl(sspi->base + SIRFSOC_SPI_CTRL),
sspi->base + SIRFSOC_SPI_CTRL);
Expand All @@ -338,18 +340,17 @@ static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)

if (IS_DMA_VALID(t)) {
struct dma_async_tx_descriptor *rx_desc, *tx_desc;
unsigned int size = t->len * sspi->word_width;

sspi->dst_start = dma_map_single(&spi->dev, sspi->rx, t->len, DMA_FROM_DEVICE);
rx_desc = dmaengine_prep_slave_single(sspi->rx_chan,
sspi->dst_start, size, DMA_DEV_TO_MEM,
sspi->dst_start, t->len, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
rx_desc->callback = spi_sirfsoc_dma_fini_callback;
rx_desc->callback_param = &sspi->rx_done;

sspi->src_start = dma_map_single(&spi->dev, (void *)sspi->tx, t->len, DMA_TO_DEVICE);
tx_desc = dmaengine_prep_slave_single(sspi->tx_chan,
sspi->src_start, size, DMA_MEM_TO_DEV,
sspi->src_start, t->len, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
tx_desc->callback = spi_sirfsoc_dma_fini_callback;
tx_desc->callback_param = &sspi->tx_done;
Expand Down Expand Up @@ -377,7 +378,7 @@ static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)
dev_err(&spi->dev, "transfer timeout\n");
dmaengine_terminate_all(sspi->rx_chan);
} else
sspi->left_rx_cnt = 0;
sspi->left_rx_word = 0;

/*
* we only wait tx-done event if transferring by DMA. for PIO,
Expand All @@ -402,7 +403,7 @@ static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)
writel(0, sspi->base + SIRFSOC_SPI_TX_RX_EN);
writel(0, sspi->base + SIRFSOC_SPI_INT_EN);

return t->len - sspi->left_rx_cnt;
return t->len - sspi->left_rx_word * sspi->word_width;
}

static void spi_sirfsoc_chipselect(struct spi_device *spi, int value)
Expand Down

0 comments on commit 692fb0f

Please sign in to comment.