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spi: atmel: Use core SPI_MASTER_MUST_[RT]X handling
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We need both RX and TX data for each transfer in any case (PIO, PDC, DMA).
So convert the driver to the core dummy buffer handling with the
SPI_MASTER_MUST_RX/SPI_MASTER_MUST_TX infrastructure.

This move changes the maximum PDC/DMA buffer handling to 65535 bytes
instead of a single page and sets master->max_dma_len to this value.

All dummy buffer management is removed from the driver.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
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Nicolas Ferre authored and Mark Brown committed Nov 25, 2016
1 parent ce24a51 commit 7910d9a
Showing 1 changed file with 35 additions and 96 deletions.
131 changes: 35 additions & 96 deletions drivers/spi/spi-atmel.c
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Original file line number Diff line number Diff line change
Expand Up @@ -303,10 +303,6 @@ struct atmel_spi {

struct completion xfer_completion;

/* scratch buffer */
void *buffer;
dma_addr_t buffer_dma;

struct atmel_spi_caps caps;

bool use_dma;
Expand All @@ -327,7 +323,7 @@ struct atmel_spi_device {
u32 csr;
};

#define BUFFER_SIZE PAGE_SIZE
#define SPI_MAX_DMA_XFER 65535 /* true for both PDC and DMA */
#define INVALID_DMA_ADDRESS 0xffffffff

/*
Expand Down Expand Up @@ -612,14 +608,10 @@ static void atmel_spi_next_xfer_single(struct spi_master *master,
cpu_relax();
}

if (xfer->tx_buf) {
if (xfer->bits_per_word > 8)
spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
else
spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
} else {
spi_writel(as, TDR, 0);
}
if (xfer->bits_per_word > 8)
spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
else
spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));

dev_dbg(master->dev.parent,
" start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
Expand Down Expand Up @@ -666,32 +658,23 @@ static void atmel_spi_next_xfer_fifo(struct spi_master *master,

/* Fill TX FIFO */
while (num_data >= 2) {
if (xfer->tx_buf) {
if (xfer->bits_per_word > 8) {
td0 = *words++;
td1 = *words++;
} else {
td0 = *bytes++;
td1 = *bytes++;
}
if (xfer->bits_per_word > 8) {
td0 = *words++;
td1 = *words++;
} else {
td0 = 0;
td1 = 0;
td0 = *bytes++;
td1 = *bytes++;
}

spi_writel(as, TDR, (td1 << 16) | td0);
num_data -= 2;
}

if (num_data) {
if (xfer->tx_buf) {
if (xfer->bits_per_word > 8)
td0 = *words++;
else
td0 = *bytes++;
} else {
td0 = 0;
}
if (xfer->bits_per_word > 8)
td0 = *words++;
else
td0 = *bytes++;

spi_writew(as, TDR, td0);
num_data--;
Expand Down Expand Up @@ -750,24 +733,14 @@ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,

/* prepare the RX dma transfer */
sg_init_table(&as->dma.sgrx, 1);
if (xfer->rx_buf) {
as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
} else {
as->dma.sgrx.dma_address = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
}
as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;

/* prepare the TX dma transfer */
sg_init_table(&as->dma.sgtx, 1);
if (xfer->tx_buf) {
as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
} else {
as->dma.sgtx.dma_address = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
memset(as->buffer, 0, len);
}
as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;

if (len > master->max_dma_len)
len = master->max_dma_len;

sg_dma_len(&as->dma.sgtx) = len;
sg_dma_len(&as->dma.sgrx) = len;
Expand Down Expand Up @@ -834,25 +807,10 @@ static void atmel_spi_next_xfer_data(struct spi_master *master,
struct atmel_spi *as = spi_master_get_devdata(master);
u32 len = *plen;

/* use scratch buffer only when rx or tx data is unspecified */
if (xfer->rx_buf)
*rx_dma = xfer->rx_dma + xfer->len - *plen;
else {
*rx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
}

if (xfer->tx_buf)
*tx_dma = xfer->tx_dma + xfer->len - *plen;
else {
*tx_dma = as->buffer_dma;
if (len > BUFFER_SIZE)
len = BUFFER_SIZE;
memset(as->buffer, 0, len);
dma_sync_single_for_device(&as->pdev->dev,
as->buffer_dma, len, DMA_TO_DEVICE);
}
*rx_dma = xfer->rx_dma + xfer->len - *plen;
*tx_dma = xfer->tx_dma + xfer->len - *plen;
if (len > master->max_dma_len)
len = master->max_dma_len;

*plen = len;
}
Expand Down Expand Up @@ -1026,16 +984,12 @@ atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer)
u16 *rxp16;
unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;

if (xfer->rx_buf) {
if (xfer->bits_per_word > 8) {
rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
*rxp16 = spi_readl(as, RDR);
} else {
rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
*rxp = spi_readl(as, RDR);
}
if (xfer->bits_per_word > 8) {
rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
*rxp16 = spi_readl(as, RDR);
} else {
spi_readl(as, RDR);
rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
*rxp = spi_readl(as, RDR);
}
if (xfer->bits_per_word > 8) {
if (as->current_remaining_bytes > 2)
Expand Down Expand Up @@ -1074,12 +1028,10 @@ atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer)
/* Read data */
while (num_data) {
rd = spi_readl(as, RDR);
if (xfer->rx_buf) {
if (xfer->bits_per_word > 8)
*words++ = rd;
else
*bytes++ = rd;
}
if (xfer->bits_per_word > 8)
*words++ = rd;
else
*bytes++ = rd;
num_data--;
}
}
Expand Down Expand Up @@ -1561,29 +1513,22 @@ static int atmel_spi_probe(struct platform_device *pdev)
master->bus_num = pdev->id;
master->num_chipselect = master->dev.of_node ? 0 : 4;
master->setup = atmel_spi_setup;
master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
master->transfer_one_message = atmel_spi_transfer_one_message;
master->cleanup = atmel_spi_cleanup;
master->auto_runtime_pm = true;
master->max_dma_len = SPI_MAX_DMA_XFER;
platform_set_drvdata(pdev, master);

as = spi_master_get_devdata(master);

/*
* Scratch buffer is used for throwaway rx and tx data.
* It's coherent to minimize dcache pollution.
*/
as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
&as->buffer_dma, GFP_KERNEL);
if (!as->buffer)
goto out_free;

spin_lock_init(&as->lock);

as->pdev = pdev;
as->regs = devm_ioremap_resource(&pdev->dev, regs);
if (IS_ERR(as->regs)) {
ret = PTR_ERR(as->regs);
goto out_free_buffer;
goto out_unmap_regs;
}
as->phybase = regs->start;
as->irq = irq;
Expand Down Expand Up @@ -1681,9 +1626,6 @@ static int atmel_spi_probe(struct platform_device *pdev)
clk_disable_unprepare(clk);
out_free_irq:
out_unmap_regs:
out_free_buffer:
dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
as->buffer_dma);
out_free:
spi_master_put(master);
return ret;
Expand All @@ -1708,9 +1650,6 @@ static int atmel_spi_remove(struct platform_device *pdev)
spi_readl(as, SR);
spin_unlock_irq(&as->lock);

dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
as->buffer_dma);

clk_disable_unprepare(as->clk);

pm_runtime_put_noidle(&pdev->dev);
Expand Down

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