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Commit dcb425f3 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Mark Brown
Browse files

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: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 05823432

drivers/spi/spi-fsl-espi.c

+63 −14
Original line number Diff line number Diff line
@@ -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 @@ static void fsl_espi_fill_tx_fifo(struct fsl_espi *espi, u32 events) 
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 */