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spi: dw: Convert the Tx done delay from SCK cycles to time

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Currently the delay in dw_spi_dma_wait_tx_done() is expressed in SCK
cycles, which requires passing a valid struct spi_transfer pointer.
This does not work for enhanced SPI memory operations, which are not
described by a spi_transfer. Compute the delay in ns or us based on an
explicit bus speed instead, so that the helper can also be used for
those transfers.

Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Link: https://patch.msgid.link/20260930071535.7947-2-changhuang.liang@starfivetech.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Changhuang Liang 2026-09-30 00:15:33 -07:00 committed by Mark Brown
parent 72d3fcf802
commit 5c99cb1516
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GPG Key ID: 24D68B725D5487D0
1 changed files with 14 additions and 6 deletions
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20
drivers/spi/spi-dw-dma.c
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@ -286,19 +286,27 @@ static inline bool dw_spi_dma_tx_busy(struct dw_spi *dws)
(DW_SPI_SR_BUSY | DW_SPI_SR_TF_EMPT)) != DW_SPI_SR_TF_EMPT;
}
static int dw_spi_dma_wait_tx_done(struct dw_spi *dws,
struct spi_transfer *xfer)
static int dw_spi_dma_wait_tx_done(struct dw_spi *dws, u32 speed_hz)
{
int retry = DW_SPI_WAIT_RETRIES;
struct spi_delay delay;
unsigned long ns, us;
u32 nents;
nents = dw_readl(dws, DW_SPI_TXFLR);
delay.unit = SPI_DELAY_UNIT_SCK;
delay.value = nents * dws->n_bytes * BITS_PER_BYTE;
ns = DIV_ROUND_UP(NSEC_PER_SEC, speed_hz) * nents *
dws->n_bytes * BITS_PER_BYTE;
if (ns <= NSEC_PER_USEC) {
delay.unit = SPI_DELAY_UNIT_NSECS;
delay.value = ns;
} else {
us = DIV_ROUND_UP(ns, NSEC_PER_USEC);
delay.unit = SPI_DELAY_UNIT_USECS;
delay.value = clamp_val(us, 0, USHRT_MAX);
}
while (dw_spi_dma_tx_busy(dws) && retry--)
spi_delay_exec(&delay, xfer);
spi_delay_exec(&delay, NULL);
if (retry < 0) {
dev_err(&dws->ctlr->dev, "Tx hanged up\n");
@ -659,7 +667,7 @@ static int dw_spi_dma_transfer(struct dw_spi *dws, struct spi_transfer *xfer)
return ret;
if (dws->ctlr->cur_msg->status == -EINPROGRESS) {
ret = dw_spi_dma_wait_tx_done(dws, xfer);
ret = dw_spi_dma_wait_tx_done(dws, xfer->effective_speed_hz);
if (ret)
return ret;
}