Unverified Commit cfe58ffc authored by Patrice Chotard's avatar Patrice Chotard Committed by Mark Brown
Browse files

spi: stm32-ospi: Optimize FIFO accesses using u16 or u32 



FIFO accesses uses u8 only for read/write.
In order to optimize throughput, add u16 or u32 read/write
accesses when possible.

Running mtd_speedtest on a 4MB sNOR partition using a
stm32mp257f-ev1 board gives the following results:

           before        after   gain
Read :  5693 KiB/s  21139 KiB/s   371%
Write:   765 KiB/s    910 KiB/s    19%

Signed-off-by: default avatarPatrice Chotard <patrice.chotard@foss.st.com>
Link: https://patch.msgid.link/20251208-upstream_qspi_ospi_updates-v2-2-62526c9467dc@foss.st.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent e35a7607

drivers/spi/spi-stm32-ospi.c

+38 −9
Original line number Diff line number Diff line
@@ -142,14 +142,32 @@ struct stm32_ospi { 
	struct mutex lock;

};



static void stm32_ospi_read_fifo(u8 *val, void __iomem *addr)

static void stm32_ospi_read_fifo(void *val, void __iomem *addr, u8 len)

{

	*val = readb_relaxed(addr);

	switch (len) {

	case sizeof(u32):

		*((u32 *)val) = readl_relaxed(addr);

		break;

	case sizeof(u16):

		*((u16 *)val) = readw_relaxed(addr);

		break;

	case sizeof(u8):

		*((u8 *)val) = readb_relaxed(addr);

	};

}



static void stm32_ospi_write_fifo(u8 *val, void __iomem *addr)

static void stm32_ospi_write_fifo(void *val, void __iomem *addr, u8 len)

{

	writeb_relaxed(*val, addr);

	switch (len) {

	case sizeof(u32):

		writel_relaxed(*((u32 *)val), addr);

		break;

	case sizeof(u16):

		writew_relaxed(*((u16 *)val), addr);

		break;

	case sizeof(u8):

		writeb_relaxed(*((u8 *)val), addr);

	};

}



static int stm32_ospi_abort(struct stm32_ospi *ospi)
@@ -172,19 +190,20 @@ static int stm32_ospi_abort(struct stm32_ospi *ospi) 
	return timeout;

}



static int stm32_ospi_poll(struct stm32_ospi *ospi, u8 *buf, u32 len, bool read)

static int stm32_ospi_poll(struct stm32_ospi *ospi, void *buf, u32 len, bool read)

{

	void __iomem *regs_base = ospi->regs_base;

	void (*fifo)(u8 *val, void __iomem *addr);

	void (*fifo)(void *val, void __iomem *addr, u8 len);

	u32 sr;

	int ret;

	u8 step;



	if (read)

		fifo = stm32_ospi_read_fifo;

	else

		fifo = stm32_ospi_write_fifo;



	while (len--) {

	while (len) {

		ret = readl_relaxed_poll_timeout_atomic(regs_base + OSPI_SR,

							sr, sr & SR_FTF, 1,

							STM32_FIFO_TIMEOUT_US);
@@ -193,7 +212,17 @@ static int stm32_ospi_poll(struct stm32_ospi *ospi, u8 *buf, u32 len, bool read) 
				len, sr);

			return ret;

		}

		fifo(buf++, regs_base + OSPI_DR);



		if (len >= sizeof(u32))

			step = sizeof(u32);

		else if (len >= sizeof(u16))

			step = sizeof(u16);

		else

			step = sizeof(u8);



		fifo(buf, regs_base + OSPI_DR, step);

		len -= step;

		buf += step;

	}



	return 0;
@@ -408,7 +437,7 @@ static int stm32_ospi_xfer(struct stm32_ospi *ospi, const struct spi_mem_op *op) 
	if (op->data.dir == SPI_MEM_DATA_IN)

		buf = op->data.buf.in;

	else

		buf = (u8 *)op->data.buf.out;

		buf = (void *)op->data.buf.out;



	return stm32_ospi_poll(ospi, buf, op->data.nbytes,

			       op->data.dir == SPI_MEM_DATA_IN);