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spi: fsl-espi: eliminate need for linearization when reading from hardware 

Eliminate need for linearization when reading from the hardware and
write to the transfer buffers directly.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Heiner Kallweit 2016-11-25 23:59:57 +01:00 committed by Mark Brown
parent 0582343284
commit dcb425f3ba
1 changed files with 63 additions and 14 deletions
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77
drivers/spi/spi-fsl-espi.c
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@ -102,6 +102,9 @@ struct fsl_espi {
struct spi_transfer *tx_t;
unsigned int tx_pos;
bool tx_done;
struct spi_transfer *rx_t;
unsigned int rx_pos;
bool rx_done;
bool swab;
unsigned int rx_len;
@ -125,6 +128,11 @@ static inline u32 fsl_espi_read_reg(struct fsl_espi *espi, int offset)
return ioread32be(espi->reg_base + offset);
}
static inline u16 fsl_espi_read_reg16(struct fsl_espi *espi, int offset)
{
return ioread16(espi->reg_base + offset);
}
static inline u8 fsl_espi_read_reg8(struct fsl_espi *espi, int offset)
{
return ioread8(espi->reg_base + offset);
@ -328,21 +336,55 @@ start:
static void fsl_espi_read_rx_fifo(struct fsl_espi *espi, u32 events)
{
u32 rx_fifo_avail = SPIE_RXCNT(events);
unsigned int rx_left;
void *rx_buf;
while (rx_fifo_avail >= min(4U, espi->rx_len) && espi->rx_len)
if (espi->rx_len >= 4) {
*(u32 *)espi->rx = fsl_espi_read_reg(espi, ESPI_SPIRF);
espi->rx += 4;
espi->rx_len -= 4;
start:
rx_left = espi->rx_t->len - espi->rx_pos;
rx_buf = espi->rx_t->rx_buf;
while (rx_fifo_avail >= min(4U, rx_left) && rx_left) {
if (rx_left >= 4) {
u32 val = fsl_espi_read_reg(espi, ESPI_SPIRF);
if (rx_buf && espi->swab)
*(u32 *)(rx_buf + espi->rx_pos) = swahb32(val);
else if (rx_buf)
*(u32 *)(rx_buf + espi->rx_pos) = val;
espi->rx_pos += 4;
rx_left -= 4;
rx_fifo_avail -= 4;
} else if (rx_left >= 2 && rx_buf && espi->swab) {
u16 val = fsl_espi_read_reg16(espi, ESPI_SPIRF);
*(u16 *)(rx_buf + espi->rx_pos) = swab16(val);
espi->rx_pos += 2;
rx_left -= 2;
rx_fifo_avail -= 2;
} else {
*(u8 *)espi->rx = fsl_espi_read_reg8(espi, ESPI_SPIRF);
espi->rx += 1;
espi->rx_len -= 1;
u8 val = fsl_espi_read_reg8(espi, ESPI_SPIRF);
if (rx_buf)
*(u8 *)(rx_buf + espi->rx_pos) = val;
espi->rx_pos += 1;
rx_left -= 1;
rx_fifo_avail -= 1;
}
}
if (!rx_left) {
if (list_is_last(&espi->rx_t->transfer_list,
espi->m_transfers)) {
espi->rx_done = true;
return;
}
espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
espi->rx_pos = 0;
/* continue with next transfer if rx fifo is not empty */
if (rx_fifo_avail)
goto start;
}
}
static void fsl_espi_setup_transfer(struct spi_device *spi,
struct spi_transfer *t)
{
@ -375,6 +417,7 @@ static void fsl_espi_setup_transfer(struct spi_device *spi,
static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct fsl_espi *espi = spi_master_get_devdata(spi->master);
unsigned int rx_len = t->len;
u32 mask, spcom;
int ret;
@ -395,6 +438,7 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
spcom |= SPCOM_RXSKIP(espi->rxskip);
espi->tx_len = espi->rxskip;
espi->rx_len = t->len - espi->rxskip;
rx_len = t->len - espi->rxskip;
espi->rx = t->rx_buf + espi->rxskip;
if (t->rx_nbits == SPI_NBITS_DUAL)
spcom |= SPCOM_DO;
@ -404,7 +448,7 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
/* enable interrupts */
mask = SPIM_DON;
if (espi->rx_len > FSL_ESPI_FIFO_SIZE)
if (rx_len > FSL_ESPI_FIFO_SIZE)
mask |= SPIM_RXT;
fsl_espi_write_reg(espi, ESPI_SPIM, mask);
@ -438,6 +482,10 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
transfer_list);
espi->tx_pos = 0;
espi->tx_done = false;
espi->rx_t = list_first_entry(&m->transfers, struct spi_transfer,
transfer_list);
espi->rx_pos = 0;
espi->rx_done = false;
espi->rxskip = fsl_espi_check_rxskip_mode(m);
if (trans->rx_nbits == SPI_NBITS_DUAL && !espi->rxskip) {
@ -445,6 +493,10 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
return -EINVAL;
}
/* In RXSKIP mode skip first transfer for reads */
if (espi->rxskip)
espi->rx_t = list_next_entry(espi->rx_t, transfer_list);
fsl_espi_copy_to_buf(m, espi);
fsl_espi_setup_transfer(spi, trans);
@ -453,9 +505,6 @@ static int fsl_espi_trans(struct spi_message *m, struct spi_transfer *trans)
if (trans->delay_usecs)
udelay(trans->delay_usecs);
if (!ret)
fsl_espi_copy_from_buf(m, espi);
return ret;
}
@ -556,13 +605,13 @@ static void fsl_espi_cleanup(struct spi_device *spi)
static void fsl_espi_cpu_irq(struct fsl_espi *espi, u32 events)
{
if (espi->rx_len)
if (!espi->rx_done)
fsl_espi_read_rx_fifo(espi, events);
if (!espi->tx_done)
fsl_espi_fill_tx_fifo(espi, events);
if (!espi->tx_done || espi->rx_len)
if (!espi->tx_done || !espi->rx_done)
return;
/* we're done, but check for errors before returning */