Make flash writes 32 bit aligned by using bounce buffers to deal with non 32 bit aligned buffers. This is required because as per TI K2G TRM[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 fail sometimes.
[1] http://www.ti.com/lit/ug/spruhy8g/spruhy8g.pdf
Signed-off-by: Vignesh R vigneshr@ti.com Acked-by: Marek Vasut marex@denx.de Acked-by: Simon Goldschmidt sgoldschmidt@de.pepperl-fuchs.com Reviewed-by: Jason Rush jarush@gmail.com Acked-by: Jason Rush jarush@gmail.com --- drivers/spi/cadence_qspi_apb.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c index a57109865d29..6d9a7941b470 100644 --- a/drivers/spi/cadence_qspi_apb.c +++ b/drivers/spi/cadence_qspi_apb.c @@ -30,6 +30,7 @@ #include <linux/errno.h> #include <wait_bit.h> #include <spi.h> +#include <malloc.h> #include "cadence_qspi.h"
#define CQSPI_REG_POLL_US 1 /* 1us */ @@ -719,9 +720,23 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat, { unsigned int page_size = plat->page_size; unsigned int remaining = n_tx; + const u8 *bb_txbuf = txbuf; + void *bounce_buf = NULL; unsigned int write_bytes; int ret;
+ /* + * Use bounce buffer for non 32 bit aligned txbuf to avoid data + * aborts + */ + if ((uintptr_t)txbuf % 4) { + bounce_buf = malloc(n_tx); + if (!bounce_buf) + return -ENOMEM; + memcpy(bounce_buf, txbuf, n_tx); + bb_txbuf = bounce_buf; + } + /* Configure the indirect read transfer bytes */ writel(n_tx, plat->regbase + CQSPI_REG_INDIRECTWRBYTES);
@@ -731,11 +746,11 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat,
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, bb_txbuf, write_bytes >> 2); + if (write_bytes % 4) + writesb(plat->ahbbase, + bb_txbuf + rounddown(write_bytes, 4), + write_bytes % 4);
ret = wait_for_bit_le32(plat->regbase + CQSPI_REG_SDRAMLEVEL, CQSPI_REG_SDRAMLEVEL_WR_MASK << @@ -745,7 +760,7 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat, goto failwr; }
- txbuf += write_bytes; + bb_txbuf += write_bytes; remaining -= write_bytes; }
@@ -760,12 +775,16 @@ int cadence_qspi_apb_indirect_write_execute(struct cadence_spi_platdata *plat, /* Clear indirect completion status */ writel(CQSPI_REG_INDIRECTWR_DONE, plat->regbase + CQSPI_REG_INDIRECTWR); + if (bounce_buf) + free(bounce_buf); return 0;
failwr: /* Cancel the indirect write */ writel(CQSPI_REG_INDIRECTWR_CANCEL, plat->regbase + CQSPI_REG_INDIRECTWR); + if (bounce_buf) + free(bounce_buf); return ret; }