[U-Boot] [PATCH v2] Revert "spi: cadence_qspi_apb: Use 32 bit indirect read transaction when possible"

[Goldschmidt Simon]

This reverts commit b63b46313ed29e9b0c36b3d6b9407f6eade40c8f.

This commit changed cadence_qspi_apb to use bouncebuf.c, which invalidates
the data cache after reading. This is meant for dma transfers only and
breaks the cadence_qspi driver which copies via cpu only: data that is
copied by the cpu is in cache only and the cache invalidation at the end
throws away this data.

Signed-off-by: Simon Goldschmidt <sgoldschmidt at de.pepperl-fuchs.com>
---

Changes for v2:
   - Rebased on top of Jason's patchset v4 "Sync DT bindings with Linux"

 drivers/spi/cadence_qspi_apb.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index 8309ab8794..c7cb33aa8f 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -627,8 +627,6 @@ int cadence_qspi_apb_indirect_read_execute(struct cadence_spi_platdata *plat,
 {
 	unsigned int remaining = n_rx;
 	unsigned int bytes_to_read = 0;
-	struct bounce_buffer bb;
-	u8 *bb_rxbuf;
 	int ret;
 
 	writel(n_rx, plat->regbase + CQSPI_REG_INDIRECTRDBYTES);
@@ -637,11 +635,6 @@ int cadence_qspi_apb_indirect_read_execute(struct cadence_spi_platdata *plat,
 	writel(CQSPI_REG_INDIRECTRD_START,
 	       plat->regbase + CQSPI_REG_INDIRECTRD);
 
-	ret = bounce_buffer_start(&bb, (void *)rxbuf, n_rx, GEN_BB_WRITE);
-	if (ret)
-		return ret;
-	bb_rxbuf = bb.bounce_buffer;
-
 	while (remaining > 0) {
 		ret = cadence_qspi_wait_for_data(plat);
 		if (ret < 0) {
@@ -655,13 +648,12 @@ int cadence_qspi_apb_indirect_read_execute(struct cadence_spi_platdata *plat,
 			bytes_to_read *= plat->fifo_width;
 			bytes_to_read = bytes_to_read > remaining ?
 					remaining : bytes_to_read;
-			readsl(plat->ahbbase, bb_rxbuf, bytes_to_read >> 2);
-			if (bytes_to_read % 4)
-				readsb(plat->ahbbase,
-				       bb_rxbuf + rounddown(bytes_to_read, 4),
-				       bytes_to_read % 4);
-
-			bb_rxbuf += bytes_to_read;
+			/* Handle non-4-byte aligned access to avoid data abort. */
+			if (((uintptr_t)rxbuf % 4) || (bytes_to_read % 4))
+				readsb(plat->ahbbase, rxbuf, bytes_to_read);
+			else
+				readsl(plat->ahbbase, rxbuf, bytes_to_read >> 2);
+			rxbuf += bytes_to_read;
 			remaining -= bytes_to_read;
 			bytes_to_read = cadence_qspi_get_rd_sram_level(plat);
 		}
@@ -678,7 +670,6 @@ int cadence_qspi_apb_indirect_read_execute(struct cadence_spi_platdata *plat,
 	/* Clear indirect completion status */
 	writel(CQSPI_REG_INDIRECTRD_DONE,
 	       plat->regbase + CQSPI_REG_INDIRECTRD);
-	bounce_buffer_stop(&bb);
 
 	return 0;
 
@@ -686,7 +677,6 @@ failrd:
 	/* Cancel the indirect read */
 	writel(CQSPI_REG_INDIRECTRD_CANCEL,
 	       plat->regbase + CQSPI_REG_INDIRECTRD);
-	bounce_buffer_stop(&bb);
 	return ret;
 }
 
-- 
2.12.2.windows.2