spi/rockchip: fix bug that cause spi transfer timed out in DMA duplex mode

In rx mode, dma must be prepared before spi is enabled.
But in tx and tr mode, spi must be enabled first.

Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 3044c6c..153269b 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -328,6 +328,8 @@
 
 	spin_unlock_irqrestore(&rs->lock, flags);
 
+	spi_enable_chip(rs, 0);
+
 	return 0;
 }
 
@@ -384,6 +386,8 @@
 	if (rs->tx)
 		wait_for_idle(rs);
 
+	spi_enable_chip(rs, 0);
+
 	return 0;
 }
 
@@ -395,8 +399,10 @@
 	spin_lock_irqsave(&rs->lock, flags);
 
 	rs->state &= ~RXBUSY;
-	if (!(rs->state & TXBUSY))
+	if (!(rs->state & TXBUSY)) {
+		spi_enable_chip(rs, 0);
 		spi_finalize_current_transfer(rs->master);
+	}
 
 	spin_unlock_irqrestore(&rs->lock, flags);
 }
@@ -512,8 +518,6 @@
 	div = max_t(u32, rs->max_freq / rs->speed, 1);
 	div = (div + 1) & 0xfffe;
 
-	spi_enable_chip(rs, 0);
-
 	writel_relaxed(cr0, rs->regs + ROCKCHIP_SPI_CTRLR0);
 
 	writel_relaxed(rs->len - 1, rs->regs + ROCKCHIP_SPI_CTRLR1);
@@ -527,8 +531,6 @@
 	spi_set_clk(rs, div);
 
 	dev_dbg(rs->dev, "cr0 0x%x, div %d\n", cr0, div);
-
-	spi_enable_chip(rs, 1);
 }
 
 static int rockchip_spi_transfer_one(
@@ -536,7 +538,7 @@
 		struct spi_device *spi,
 		struct spi_transfer *xfer)
 {
-	int ret = 0;
+	int ret = 1;
 	struct rockchip_spi *rs = spi_master_get_devdata(master);
 
 	WARN_ON(readl_relaxed(rs->regs + ROCKCHIP_SPI_SSIENR) &&
@@ -568,17 +570,27 @@
 		rs->tmode = CR0_XFM_RO;
 
 	/* we need prepare dma before spi was enabled */
-	if (master->can_dma && master->can_dma(master, spi, xfer)) {
+	if (master->can_dma && master->can_dma(master, spi, xfer))
 		rs->use_dma = 1;
-		rockchip_spi_prepare_dma(rs);
-	} else {
+	else
 		rs->use_dma = 0;
-	}
 
 	rockchip_spi_config(rs);
 
-	if (!rs->use_dma)
+	if (rs->use_dma) {
+		if (rs->tmode == CR0_XFM_RO) {
+			/* rx: dma must be prepared first */
+			rockchip_spi_prepare_dma(rs);
+			spi_enable_chip(rs, 1);
+		} else {
+			/* tx or tr: spi must be enabled first */
+			spi_enable_chip(rs, 1);
+			rockchip_spi_prepare_dma(rs);
+		}
+	} else {
+		spi_enable_chip(rs, 1);
 		ret = rockchip_spi_pio_transfer(rs);
+	}
 
 	return ret;
 }