[PATCH 2/6] ata: sata_mv: clear SERROR and en/disable EDMA

[Steffen Trumtrar]

SControl registers shouldn't be accessed when EDMA is enabled.
Also clear SError before any accesses. This register will show if
anything went wrong with the phy accesses.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
---
 drivers/ata/sata_mv.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 3f77e8f2e8..c94ad2ca36 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -37,10 +37,13 @@ static void ata_ioports_init(struct ata_ioports *io,
 #define REG_WINDOW_BASE(n)		((n) * 0x10 + 0x34)
 
 #define REG_EDMA_COMMAND(n)		((n) * 0x2000 + 0x2028)
+#define EDMA_EN				(1 << 0)	/* enable EDMA */
+#define EDMA_DS				(1 << 1)	/* disable EDMA; self-negated */
 #define REG_EDMA_COMMAND__EATARST	0x00000004
 
 #define REG_ATA_BASE			0x2100
 #define REG_SSTATUS(n)			((n) * 0x2000 + 0x2300)
+#define REG_SERROR(n)			((n) * 0x2000 + 0x2304)
 #define REG_SCONTROL(n)			((n) * 0x2000 + 0x2308)
 #define REG_SCONTROL__DET		0x0000000f
 #define REG_SCONTROL__DET__INIT		0x00000001
@@ -74,6 +77,19 @@ static int mv_sata_probe(struct device_d *dev)
 	writel(0x7fff0e01, base + REG_WINDOW_CONTROL(0));
 	writel(0, base + REG_WINDOW_BASE(0));
 
+	/* Clear SError */
+	writel(0x0, base + REG_SERROR(0));
+	/* disable EDMA */
+	writel(EDMA_DS, base + REG_EDMA_COMMAND(0));
+	/* Wait for the chip to confirm eDMA is off. */
+	ret = wait_on_timeout(10 * MSECOND,
+				(readl(base + REG_EDMA_COMMAND(0)) & EDMA_EN) == 0);
+	if (ret) {
+		dev_err(dev, "Failed to wait for eDMA off (sstatus=0x%08x)\n",
+			readl(base + REG_SSTATUS(0)));
+		return ret;
+	}
+
 	writel(REG_EDMA_COMMAND__EATARST, base + REG_EDMA_COMMAND(0));
 	udelay(25);
 	writel(0x0, base + REG_EDMA_COMMAND(0));
@@ -104,6 +120,9 @@ static int mv_sata_probe(struct device_d *dev)
 
 	dev->priv = ide;
 
+	/* enable EDMA */
+	writel(EDMA_EN, base + REG_EDMA_COMMAND(0));
+
 	ret = ide_port_register(ide);
 	if (ret)
 		free(ide);
-- 
2.30.2