[PATCH] sata_nv: fix ADMA ATAPI issues with memory over 4GB (v3)

[Robert Hancock <hancockr@shaw.ca>]

This fixes some problems with ATAPI devices on nForce4 controllers in ADMA mode
on systems with memory located above 4GB. We need to delay setting the 64-bit
DMA mask until the PRD table and padding buffer are allocated so that they don't
get allocated above 4GB and break legacy mode (which is needed for ATAPI
devices).

Signed-off-by: Robert Hancock <hancockr@shaw.ca>

--- linux-2.6.24-rc3-git1edit/drivers/ata/sata_nv.c.before2	2007-11-22 19:42:28.000000000 -0600
+++ linux-2.6.24-rc3-git1edit/drivers/ata/sata_nv.c	2007-11-22 19:48:25.000000000 -0600
@@ -247,6 +247,7 @@
 	void __iomem		*ctl_block;
 	void __iomem		*gen_block;
 	void __iomem		*notifier_clear_block;
+	u64			adma_dma_mask;
 	u8			flags;
 	int			last_issue_ncq;
 };
@@ -748,7 +749,7 @@
 		adma_enable = 0;
 		nv_adma_register_mode(ap);
 	} else {
-		bounce_limit = *ap->dev->dma_mask;
+		bounce_limit = pp->adma_dma_mask;
 		segment_boundary = NV_ADMA_DMA_BOUNDARY;
 		sg_tablesize = NV_ADMA_SGTBL_TOTAL_LEN;
 		adma_enable = 1;
@@ -1134,10 +1135,20 @@
 	void *mem;
 	dma_addr_t mem_dma;
 	void __iomem *mmio;
+	struct pci_dev *pdev = to_pci_dev(dev);
 	u16 tmp;
 
 	VPRINTK("ENTER\n");
 
+	/* Ensure DMA mask is set to 32-bit before allocating legacy PRD and
+	   pad buffers */
+	rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (rc)
+		return rc;
+	rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+	if (rc)
+		return rc;
+
 	rc = ata_port_start(ap);
 	if (rc)
 		return rc;
@@ -1153,6 +1164,15 @@
 	pp->notifier_clear_block = pp->gen_block +
 	       NV_ADMA_NOTIFIER_CLEAR + (4 * ap->port_no);
 
+	/* Now that the legacy PRD and padding buffer are allocated we can
+	   safely raise the DMA mask to allocate the CPB/APRD table.
+	   These are allowed to fail since we store the value that ends up
+	   being used to set as the bounce limit in slave_config later if
+	   needed. */
+	pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
+	pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+	pp->adma_dma_mask = *dev->dma_mask;
+
 	mem = dmam_alloc_coherent(dev, NV_ADMA_PORT_PRIV_DMA_SZ,
 				  &mem_dma, GFP_KERNEL);
 	if (!mem)
@@ -2414,12 +2434,6 @@
 	hpriv->type = type;
 	host->private_data = hpriv;
 
-	/* set 64bit dma masks, may fail */
-	if (type == ADMA) {
-		if (pci_set_dma_mask(pdev, DMA_64BIT_MASK) == 0)
-			pci_set_consistent_dma_mask(pdev, DMA_64BIT_MASK);
-	}
-
 	/* request and iomap NV_MMIO_BAR */
 	rc = pcim_iomap_regions(pdev, 1 << NV_MMIO_BAR, DRV_NAME);
 	if (rc)