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Subject[PATCH v3] spi: mediatek: Don't modify spi_transfer when transfer.
Date
Mediatek SPI driver modifies some fields (tx_buf, rx_buf, len, tx_dma,
rx_dma) of the spi_transfer* passed in when doing transfer_one and in
interrupt handler. This is somewhat unexpected, and there are some
caller (e.g. Cr50 spi driver) that reuse the spi_transfer for multiple
messages. Add a field to record how many bytes have been transferred,
and calculate the right len / buffer based on it instead.

Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
drivers/spi/spi-mt65xx.c | 37 +++++++++++++++++++++----------------
1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
index 86bf45667a040..3dc31627c6558 100644
--- a/drivers/spi/spi-mt65xx.c
+++ b/drivers/spi/spi-mt65xx.c
@@ -98,6 +98,7 @@ struct mtk_spi {
struct clk *parent_clk, *sel_clk, *spi_clk;
struct spi_transfer *cur_transfer;
u32 xfer_len;
+ u32 num_xfered;
struct scatterlist *tx_sgl, *rx_sgl;
u32 tx_sgl_len, rx_sgl_len;
const struct mtk_spi_compatible *dev_comp;
@@ -385,6 +386,7 @@ static int mtk_spi_fifo_transfer(struct spi_master *master,

mdata->cur_transfer = xfer;
mdata->xfer_len = min(MTK_SPI_MAX_FIFO_SIZE, xfer->len);
+ mdata->num_xfered = 0;
mtk_spi_prepare_transfer(master, xfer);
mtk_spi_setup_packet(master);

@@ -415,6 +417,7 @@ static int mtk_spi_dma_transfer(struct spi_master *master,
mdata->tx_sgl_len = 0;
mdata->rx_sgl_len = 0;
mdata->cur_transfer = xfer;
+ mdata->num_xfered = 0;

mtk_spi_prepare_transfer(master, xfer);

@@ -482,7 +485,7 @@ static int mtk_spi_setup(struct spi_device *spi)

static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
{
- u32 cmd, reg_val, cnt, remainder;
+ u32 cmd, reg_val, cnt, remainder, len;
struct spi_master *master = dev_id;
struct mtk_spi *mdata = spi_master_get_devdata(master);
struct spi_transfer *trans = mdata->cur_transfer;
@@ -497,36 +500,38 @@ static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
if (trans->rx_buf) {
cnt = mdata->xfer_len / 4;
ioread32_rep(mdata->base + SPI_RX_DATA_REG,
- trans->rx_buf, cnt);
+ trans->rx_buf + mdata->num_xfered, cnt);
remainder = mdata->xfer_len % 4;
if (remainder > 0) {
reg_val = readl(mdata->base + SPI_RX_DATA_REG);
- memcpy(trans->rx_buf + (cnt * 4),
- &reg_val, remainder);
+ memcpy(trans->rx_buf +
+ mdata->num_xfered +
+ (cnt * 4),
+ &reg_val,
+ remainder);
}
}

- trans->len -= mdata->xfer_len;
- if (!trans->len) {
+ mdata->num_xfered += mdata->xfer_len;
+ if (mdata->num_xfered == trans->len) {
spi_finalize_current_transfer(master);
return IRQ_HANDLED;
}

- if (trans->tx_buf)
- trans->tx_buf += mdata->xfer_len;
- if (trans->rx_buf)
- trans->rx_buf += mdata->xfer_len;
-
- mdata->xfer_len = min(MTK_SPI_MAX_FIFO_SIZE, trans->len);
+ len = trans->len - mdata->num_xfered;
+ mdata->xfer_len = min(MTK_SPI_MAX_FIFO_SIZE, len);
mtk_spi_setup_packet(master);

- cnt = trans->len / 4;
- iowrite32_rep(mdata->base + SPI_TX_DATA_REG, trans->tx_buf, cnt);
+ cnt = len / 4;
+ iowrite32_rep(mdata->base + SPI_TX_DATA_REG,
+ trans->tx_buf + mdata->num_xfered, cnt);

- remainder = trans->len % 4;
+ remainder = len % 4;
if (remainder > 0) {
reg_val = 0;
- memcpy(&reg_val, trans->tx_buf + (cnt * 4), remainder);
+ memcpy(&reg_val,
+ trans->tx_buf + (cnt * 4) + mdata->num_xfered,
+ remainder);
writel(reg_val, mdata->base + SPI_TX_DATA_REG);
}

--
2.19.0.rc2.392.g5ba43deb5a-goog
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