pl022_spi: simplify receive of remaining data

If the expected number of packets are not received during the
transmit+receive cycle, just receive the remaining data after the
cycle if the Receive FIFO (SSPSR_RNE) is not empty, without depending
on the busy (SSPSR_BSY) flag, else we might miss reading some data as
indicated in [1].

LINK: [1] OP-TEE#1461 (comment)

Signed-off-by: Victor Chong <victor.chong@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>

core/drivers/pl022_spi.c

@@ -166,11 +166,10 @@ static enum spi_result pl022_txrx8(struct spi_chip *chip, uint8_t *wdat,
 	/* Capture remaining rdat not read above */
 	if (rdat) {
 		while ((j < num_pkts) &&
-			(io_read8(pd->base + SSPSR) & SSPSR_BSY))
-			if (io_read8(pd->base + SSPSR) & SSPSR_RNE) {
-				/* rx 1 packet */
-				rdat[j++] = io_read8(pd->base + SSPDR);
-			}
+		       (io_read8(pd->base + SSPSR) & SSPSR_RNE)) {
+			/* rx 1 packet */
+			rdat[j++] = io_read8(pd->base + SSPDR);
+		}
 
 		if (j < num_pkts) {
 			EMSG("Packets requested %zu, received %zu",
@@ -212,11 +211,10 @@ static enum spi_result pl022_txrx16(struct spi_chip *chip, uint16_t *wdat,
 	/* Capture remaining rdat not read above */
 	if (rdat) {
 		while ((j < num_pkts) &&
-			(io_read8(pd->base + SSPSR) & SSPSR_BSY))
-			if (io_read8(pd->base + SSPSR) & SSPSR_RNE) {
-				/* rx 1 packet */
-				rdat[j++] = io_read8(pd->base + SSPDR);
-			}
+		       (io_read8(pd->base + SSPSR) & SSPSR_RNE)) {
+			/* rx 1 packet */
+			rdat[j++] = io_read8(pd->base + SSPDR);
+		}
 
 		if (j < num_pkts) {
 			EMSG("Packets requested %zu, received %zu",