[PATCH 2/5] spi: atmel: Use core SPI_MASTER_MUST_[RT]X handling
From: Nicolas Ferre
Date: Thu Nov 24 2016 - 06:25:29 EST
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@xxxxxxxxx>
---
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