Revert "spi: cadence_qspi_apb: Use 32 bit indirect read transaction when possible"

This reverts commit b63b46313e.

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@de.pepperl-fuchs.com>
Signed-off-by: Vignesh R <vigneshr@ti.com>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Jason Rush <jarush@gmail.com>
Acked-by: Jason Rush <jarush@gmail.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

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 +648,16 @@ 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 +674,6 @@ 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 +681,6 @@ failrd:
 	/* Cancel the indirect read */
 	writel(CQSPI_REG_INDIRECTRD_CANCEL,
 	       plat->regbase + CQSPI_REG_INDIRECTRD);
-	bounce_buffer_stop(&bb);
 	return ret;
 }