spi: rockchip: Wait for STB status in slave mode tx_xfer

After ROCKCHIP_SPI_VER2_TYPE2, SR->STB is a more accurate judgment
bit for spi slave transmition.
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Link: https://lore.kernel.org/r/20210621104800.19088-5-jon.lin@rock-chips.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-rockchip.c

@@ -116,13 +116,14 @@
 #define BAUDR_SCKDV_MIN				2
 #define BAUDR_SCKDV_MAX				65534
 
-/* Bit fields in SR, 5bit */
-#define SR_MASK						0x1f
+/* Bit fields in SR, 6bit */
+#define SR_MASK						0x3f
 #define SR_BUSY						(1 << 0)
 #define SR_TF_FULL					(1 << 1)
 #define SR_TF_EMPTY					(1 << 2)
 #define SR_RF_EMPTY					(1 << 3)
 #define SR_RF_FULL					(1 << 4)
+#define SR_SLAVE_TX_BUSY				(1 << 5)
 
 /* Bit fields in ISR, IMR, ISR, RISR, 5bit */
 #define INT_MASK					0x1f
@@ -197,13 +198,19 @@ static inline void spi_enable_chip(struct rockchip_spi *rs, bool enable)
 	writel_relaxed((enable ? 1U : 0U), rs->regs + ROCKCHIP_SPI_SSIENR);
 }
 
-static inline void wait_for_idle(struct rockchip_spi *rs)
+static inline void wait_for_tx_idle(struct rockchip_spi *rs, bool slave_mode)
 {
 	unsigned long timeout = jiffies + msecs_to_jiffies(5);
 
 	do {
+		if (slave_mode) {
+			if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_SLAVE_TX_BUSY) &&
+			    !((readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY)))
+				return;
+		} else {
 			if (!(readl_relaxed(rs->regs + ROCKCHIP_SPI_SR) & SR_BUSY))
 				return;
+		}
 	} while (!time_after(jiffies, timeout));
 
 	dev_warn(rs->dev, "spi controller is in busy state!\n");
@@ -383,7 +390,7 @@ static void rockchip_spi_dma_txcb(void *data)
 		return;
 
 	/* Wait until the FIFO data completely. */
-	wait_for_idle(rs);
+	wait_for_tx_idle(rs, ctlr->slave);
 
 	spi_enable_chip(rs, false);
 	spi_finalize_current_transfer(ctlr);
@@ -545,7 +552,7 @@ static int rockchip_spi_config(struct rockchip_spi *rs,
 	else
 		writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);
 
-	writel_relaxed(rs->fifo_len / 2, rs->regs + ROCKCHIP_SPI_DMATDLR);
+	writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_DMATDLR);
 	writel_relaxed(rockchip_spi_calc_burst_size(xfer->len / rs->n_bytes) - 1,
 		       rs->regs + ROCKCHIP_SPI_DMARDLR);
 	writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);