From: Jeff Garzik <jeff@garzik.org>
Date: Tue, 7 Apr 2009 23:18:32 +0000 (-0400)
Subject: [libata] sata_sil: disable DMA engine in sil_freeze()
X-Git-Tag: v2.6.32-rc1~717^2~23
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2fc37adba0fb05760b8635c6706773af828ccf3c;p=pandora-kernel.git

[libata] sata_sil: disable DMA engine in sil_freeze()

We must disable the DMA engine before accessing taskfile registers.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---

diff --git a/drivers/ata/sata_sil.c b/drivers/ata/sata_sil.c
index 35bd5cc7f285..3cb69d5fb817 100644
--- a/drivers/ata/sata_sil.c
+++ b/drivers/ata/sata_sil.c
@@ -565,6 +565,19 @@ static void sil_freeze(struct ata_port *ap)
 	tmp |= SIL_MASK_IDE0_INT << ap->port_no;
 	writel(tmp, mmio_base + SIL_SYSCFG);
 	readl(mmio_base + SIL_SYSCFG);	/* flush */
+
+	/* Ensure DMA_ENABLE is off.
+	 *
+	 * This is because the controller will not give us access to the
+	 * taskfile registers while a DMA is in progress
+	 */
+	iowrite8(ioread8(ap->ioaddr.bmdma_addr) & ~SIL_DMA_ENABLE,
+		 ap->ioaddr.bmdma_addr);
+
+	/* According to ata_bmdma_stop, an HDMA transition requires
+	 * on PIO cycle. But we can't read a taskfile register.
+	 */
+	ioread8(ap->ioaddr.bmdma_addr);
 }
 
 static void sil_thaw(struct ata_port *ap)