[U-Boot] [PATCH] spi: cadence_qspi_apb: Use 32 bit indirect write transaction when possible
Marek Vasut
marex at denx.de
Sat Nov 12 22:43:36 CET 2016
On 11/10/2016 06:18 AM, Vignesh R wrote:
> According to Section 11.15.4.9.2 Indirect Write Controller of K2G SoC
> TRM SPRUHY8D[1], the external master is only permitted to issue 32-bit
> data interface writes until the last word of an indirect transfer
> otherwise indirect writes is known to fails sometimes. So, make sure
> that QSPI indirect writes are 32 bit sized except for the last write.
>
> [1]www.ti.com/lit/ug/spruhy8d/spruhy8d.pdf
>
> Signed-off-by: Vignesh R <vigneshr at ti.com>
I would if it wouldn't be better to use bounce buffer for the txbuf .
See common/bouncebuf.c
> ---
> drivers/spi/cadence_qspi_apb.c | 41 +++++++++++++++++++++++++++++++----------
> 1 file changed, 31 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
> index e285d3c1e761..0115700ef6a7 100644
> --- a/drivers/spi/cadence_qspi_apb.c
> +++ b/drivers/spi/cadence_qspi_apb.c
> @@ -739,23 +739,44 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat,
> {
> unsigned int page_size = plat->page_size;
> unsigned int remaining = n_tx;
> - unsigned int write_bytes;
> + unsigned int write_bytes = 0;
> int ret;
>
> + /* Handle non-4-byte aligned access to avoid data abort. */
> + if ((uintptr_t) txbuf % 4) {
> + write_bytes = n_tx > 3 ? 4 - ((uintptr_t)txbuf % 4) : n_tx;
> + /* Configure the indirect read transfer bytes */
> + writel(write_bytes, plat->regbase + CQSPI_REG_INDIRECTWRBYTES);
> + /* Start the indirect write transfer */
> + writel(CQSPI_REG_INDIRECTWR_START_MASK,
> + plat->regbase + CQSPI_REG_INDIRECTWR);
> + writesb(plat->ahbbase, txbuf, write_bytes);
> + txbuf += write_bytes;
> + remaining -= write_bytes;
> + if (remaining > 0) {
> + u32 start_addr = readl(plat->regbase +
> + CQSPI_REG_INDIRECTWRSTARTADDR);
> + start_addr += write_bytes;
> + writel(start_addr, plat->regbase +
> + CQSPI_REG_INDIRECTWRSTARTADDR);
> + }
> + }
> +
> /* Configure the indirect read transfer bytes */
> - writel(n_tx, plat->regbase + CQSPI_REG_INDIRECTWRBYTES);
> + writel(n_tx - write_bytes, plat->regbase + CQSPI_REG_INDIRECTWRBYTES);
>
> - /* Start the indirect write transfer */
> - writel(CQSPI_REG_INDIRECTWR_START_MASK,
> - plat->regbase + CQSPI_REG_INDIRECTWR);
> + if (remaining > 0)
> + writel(CQSPI_REG_INDIRECTWR_START_MASK,
> + plat->regbase + CQSPI_REG_INDIRECTWR);
>
> while (remaining > 0) {
> write_bytes = remaining > page_size ? page_size : remaining;
> - /* Handle non-4-byte aligned access to avoid data abort. */
> - if (((uintptr_t)txbuf % 4) || (write_bytes % 4))
> - writesb(plat->ahbbase, txbuf, write_bytes);
> - else
> - writesl(plat->ahbbase, txbuf, write_bytes >> 2);
> +
> + writesl(plat->ahbbase, txbuf, write_bytes >> 2);
> + if (write_bytes % 4)
> + writesb(plat->ahbbase,
> + txbuf + rounddown(write_bytes, 4),
> + write_bytes % 4);
>
> ret = wait_for_bit("QSPI", plat->regbase + CQSPI_REG_SDRAMLEVEL,
> CQSPI_REG_SDRAMLEVEL_WR_MASK <<
>
--
Best regards,
Marek Vasut
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