[PATCH 2/5] spi: atmel: Use core SPI_MASTER_MUST_[RT]X handling
Nicolas Ferre
nicolas.ferre at atmel.com
Thu Nov 24 03:24:58 PST 2016
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 at atmel.com>
---
drivers/spi/spi-atmel.c | 131 +++++++++++++-----------------------------------
1 file changed, 35 insertions(+), 96 deletions(-)
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 68e22bf94647..d0a56e11e148 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -304,10 +304,6 @@ struct atmel_spi {
struct completion xfer_completion;
- /* scratch buffer */
- void *buffer;
- dma_addr_t buffer_dma;
-
struct atmel_spi_caps caps;
bool use_dma;
@@ -328,7 +324,7 @@ 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
/*
@@ -613,14 +609,10 @@ 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",
@@ -667,17 +659,12 @@ 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);
@@ -685,14 +672,10 @@ static void atmel_spi_next_xfer_fifo(struct spi_master *master,
}
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--;
@@ -751,24 +734,14 @@ 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;
@@ -835,25 +808,10 @@ 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;
}
@@ -1027,16 +985,12 @@ 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)
@@ -1075,12 +1029,10 @@ 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--;
}
}
@@ -1562,29 +1514,22 @@ 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;
@@ -1685,9 +1630,6 @@ 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;
@@ -1712,9 +1654,6 @@ 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);
--
2.9.0
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