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spi: rockchip: use irq rather than polling 

Register an interrupt handler to fill/empty the
tx and rx fifos rather than busy-looping.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Emil Renner Berthing 2018-10-31 11:57:09 +01:00 committed by Mark Brown
parent 74b7efa82b
commit 01b59ce5da
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 95 additions and 66 deletions
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161
drivers/spi/spi-rockchip.c
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@ -172,6 +172,11 @@ struct rockchip_spi {
dma_addr_t dma_addr_rx;
dma_addr_t dma_addr_tx;
const void *tx;
void *rx;
unsigned int tx_left;
unsigned int rx_left;
atomic_t state;
/*depth of the FIFO buffer */
@ -182,11 +187,6 @@ struct rockchip_spi {
u8 n_bytes;
u8 rsd;
const void *tx;
const void *tx_end;
void *rx;
void *rx_end;
bool cs_asserted[ROCKCHIP_SPI_MAX_CS_NUM];
};
@ -222,24 +222,6 @@ static u32 get_fifo_len(struct rockchip_spi *rs)
return (fifo == 31) ? 0 : fifo;
}
static inline u32 tx_max(struct rockchip_spi *rs)
{
u32 tx_left, tx_room;
tx_left = (rs->tx_end - rs->tx) / rs->n_bytes;
tx_room = rs->fifo_len - readl_relaxed(rs->regs + ROCKCHIP_SPI_TXFLR);
return min(tx_left, tx_room);
}
static inline u32 rx_max(struct rockchip_spi *rs)
{
u32 rx_left = (rs->rx_end - rs->rx) / rs->n_bytes;
u32 rx_room = (u32)readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);
return min(rx_left, rx_room);
}
static void rockchip_spi_set_cs(struct spi_device *spi, bool enable)
{
struct spi_master *master = spi->master;
@ -277,6 +259,9 @@ static void rockchip_spi_handle_err(struct spi_master *master,
*/
spi_enable_chip(rs, false);
/* make sure all interrupts are masked */
writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
if (atomic_read(&rs->state) & TXDMA)
dmaengine_terminate_async(master->dma_tx);
@ -286,14 +271,17 @@ static void rockchip_spi_handle_err(struct spi_master *master,
static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
{
u32 max = tx_max(rs);
u32 txw = 0;
u32 tx_free = rs->fifo_len - readl_relaxed(rs->regs + ROCKCHIP_SPI_TXFLR);
u32 words = min(rs->tx_left, tx_free);
rs->tx_left -= words;
for (; words; words--) {
u32 txw;
while (max--) {
if (rs->n_bytes == 1)
txw = *(u8 *)(rs->tx);
txw = *(u8 *)rs->tx;
else
txw = *(u16 *)(rs->tx);
txw = *(u16 *)rs->tx;
writel_relaxed(txw, rs->regs + ROCKCHIP_SPI_TXDR);
rs->tx += rs->n_bytes;
@ -302,46 +290,72 @@ static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
static void rockchip_spi_pio_reader(struct rockchip_spi *rs)
{
u32 max = rx_max(rs);
u32 rxw;
u32 words = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);
u32 rx_left = rs->rx_left - words;
/* the hardware doesn't allow us to change fifo threshold
* level while spi is enabled, so instead make sure to leave
* enough words in the rx fifo to get the last interrupt
* exactly when all words have been received
*/
if (rx_left) {
u32 ftl = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFTLR) + 1;
if (rx_left < ftl) {
rx_left = ftl;
words = rs->rx_left - rx_left;
}
}
rs->rx_left = rx_left;
for (; words; words--) {
u32 rxw = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXDR);
if (!rs->rx)
continue;
while (max--) {
rxw = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXDR);
if (rs->n_bytes == 1)
*(u8 *)(rs->rx) = (u8)rxw;
*(u8 *)rs->rx = (u8)rxw;
else
*(u16 *)(rs->rx) = (u16)rxw;
*(u16 *)rs->rx = (u16)rxw;
rs->rx += rs->n_bytes;
}
}
static int rockchip_spi_pio_transfer(struct rockchip_spi *rs)
static irqreturn_t rockchip_spi_isr(int irq, void *dev_id)
{
int remain = 0;
struct spi_master *master = dev_id;
struct rockchip_spi *rs = spi_master_get_devdata(master);
if (rs->tx_left)
rockchip_spi_pio_writer(rs);
rockchip_spi_pio_reader(rs);
if (!rs->rx_left) {
spi_enable_chip(rs, false);
writel_relaxed(0, rs->regs + ROCKCHIP_SPI_IMR);
spi_finalize_current_transfer(master);
}
return IRQ_HANDLED;
}
static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
struct spi_transfer *xfer)
{
rs->tx = xfer->tx_buf;
rs->rx = xfer->rx_buf;
rs->tx_left = rs->tx ? xfer->len / rs->n_bytes : 0;
rs->rx_left = xfer->len / rs->n_bytes;
writel_relaxed(INT_RF_FULL, rs->regs + ROCKCHIP_SPI_IMR);
spi_enable_chip(rs, true);
do {
if (rs->tx) {
remain = rs->tx_end - rs->tx;
rockchip_spi_pio_writer(rs);
}
if (rs->tx_left)
rockchip_spi_pio_writer(rs);
if (rs->rx) {
remain = rs->rx_end - rs->rx;
rockchip_spi_pio_reader(rs);
}
cpu_relax();
} while (remain);
/* If tx, wait until the FIFO data completely. */
if (rs->tx)
wait_for_idle(rs);
spi_enable_chip(rs, false);
return 0;
/* 1 means the transfer is in progress */
return 1;
}
static void rockchip_spi_dma_rxcb(void *data)
@ -465,7 +479,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs,
cr0 |= CR0_XFM_TR << CR0_XFM_OFFSET;
else if (xfer->rx_buf)
cr0 |= CR0_XFM_RO << CR0_XFM_OFFSET;
else
else if (use_dma)
cr0 |= CR0_XFM_TO << CR0_XFM_OFFSET;
if (use_dma) {
@ -484,8 +498,14 @@ static void rockchip_spi_config(struct rockchip_spi *rs,
else
writel_relaxed((xfer->len * 2) - 1, rs->regs + ROCKCHIP_SPI_CTRLR1);
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_TXFTLR);
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
/* unfortunately setting the fifo threshold level to generate an
* interrupt exactly when the fifo is full doesn't seem to work,
* so we need the strict inequality here
*/
if (xfer->len < rs->fifo_len)
writel_relaxed(xfer->len - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
else
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_DMATDLR);
writel_relaxed(0, rs->regs + ROCKCHIP_SPI_DMARDLR);
@ -527,11 +547,6 @@ static int rockchip_spi_transfer_one(
rs->n_bytes = xfer->bits_per_word >> 3;
rs->tx = xfer->tx_buf;
rs->tx_end = rs->tx + xfer->len;
rs->rx = xfer->rx_buf;
rs->rx_end = rs->rx + xfer->len;
use_dma = master->can_dma ? master->can_dma(master, spi, xfer) : false;
rockchip_spi_config(rs, spi, xfer, use_dma);
@ -539,7 +554,7 @@ static int rockchip_spi_transfer_one(
if (use_dma)
return rockchip_spi_prepare_dma(rs, master, xfer);
return rockchip_spi_pio_transfer(rs);
return rockchip_spi_prepare_irq(rs, xfer);
}
static bool rockchip_spi_can_dma(struct spi_master *master,
@ -547,8 +562,13 @@ static bool rockchip_spi_can_dma(struct spi_master *master,
struct spi_transfer *xfer)
{
struct rockchip_spi *rs = spi_master_get_devdata(master);
unsigned int bytes_per_word = xfer->bits_per_word <= 8 ? 1 : 2;
return (xfer->len > rs->fifo_len);
/* if the numbor of spi words to transfer is less than the fifo
* length we can just fill the fifo and wait for a single irq,
* so don't bother setting up dma
*/
return xfer->len / bytes_per_word >= rs->fifo_len;
}
static int rockchip_spi_probe(struct platform_device *pdev)
@ -603,6 +623,15 @@ static int rockchip_spi_probe(struct platform_device *pdev)
spi_enable_chip(rs, false);
ret = platform_get_irq(pdev, 0);
if (ret < 0)
goto err_disable_spiclk;
ret = devm_request_threaded_irq(&pdev->dev, ret, rockchip_spi_isr, NULL,
IRQF_ONESHOT, dev_name(&pdev->dev), master);
if (ret)
goto err_disable_spiclk;
rs->dev = &pdev->dev;
rs->freq = clk_get_rate(rs->spiclk);