ntb: intel: add hw workaround for NTB BAR alignment

Add NTB_HWERR_BAR_ALIGN hw errata flag to work around issue where the
aligment for the XLAT base must be BAR size aligned rather than 4k page
aligned. On ICX platform, the XLAT base can be 4k page size aligned
rather than BAR size aligned unlike the previous gen Intel NTB. However,
a silicon errata prevented this from working as expected and a workaround
is introduced to resolve the issue.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/ntb/hw/intel/ntb_hw_gen1.h

@@ -140,6 +140,7 @@
 #define NTB_HWERR_SB01BASE_LOCKUP	BIT_ULL(1)
 #define NTB_HWERR_B2BDOORBELL_BIT14	BIT_ULL(2)
 #define NTB_HWERR_MSIX_VECTOR32_BAD	BIT_ULL(3)
+#define NTB_HWERR_BAR_ALIGN		BIT_ULL(4)
 
 extern struct intel_b2b_addr xeon_b2b_usd_addr;
 extern struct intel_b2b_addr xeon_b2b_dsd_addr;

drivers/ntb/hw/intel/ntb_hw_gen4.c

@@ -177,6 +177,9 @@ int gen4_init_dev(struct intel_ntb_dev *ndev)
 
 	ndev->reg = &gen4_reg;
 
+	if (pdev_is_ICX(pdev))
+		ndev->hwerr_flags |= NTB_HWERR_BAR_ALIGN;
+
 	ppd1 = ioread32(ndev->self_mmio + GEN4_PPD1_OFFSET);
 	ndev->ntb.topo = gen4_ppd_topo(ndev, ppd1);
 	dev_dbg(&pdev->dev, "ppd %#x topo %s\n", ppd1,
@@ -342,9 +345,14 @@ static int intel_ntb4_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
 	else
 		mw_size = bar_size;
 
-	/* hardware requires that addr is aligned to bar size */
-	if (addr & (bar_size - 1))
-		return -EINVAL;
+	if (ndev->hwerr_flags & NTB_HWERR_BAR_ALIGN) {
+		/* hardware requires that addr is aligned to bar size */
+		if (addr & (bar_size - 1))
+			return -EINVAL;
+	} else {
+		if (addr & (PAGE_SIZE - 1))
+			return -EINVAL;
+	}
 
 	/* make sure the range fits in the usable mw size */
 	if (size > mw_size)
@@ -353,7 +361,6 @@ static int intel_ntb4_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
 	mmio = ndev->self_mmio;
 	xlat_reg = ndev->xlat_reg->bar2_xlat + (idx * 0x10);
 	limit_reg = ndev->xlat_reg->bar2_limit + (idx * 0x10);
-	idx_reg = ndev->xlat_reg->bar2_idx + (idx * 0x2);
 	base = pci_resource_start(ndev->ntb.pdev, bar);
 
 	/* Set the limit if supported, if size is not mw_size */
@@ -387,16 +394,19 @@ static int intel_ntb4_mw_set_trans(struct ntb_dev *ntb, int pidx, int idx,
 
 	dev_dbg(&ntb->pdev->dev, "BAR %d IMXLMT: %#Lx\n", bar, reg_val);
 
-	iowrite16(base_idx, mmio + idx_reg);
-	reg_val16 = ioread16(mmio + idx_reg);
-	if (reg_val16 != base_idx) {
-		iowrite64(base, mmio + limit_reg);
-		iowrite64(0, mmio + xlat_reg);
-		iowrite16(0, mmio + idx_reg);
-		return -EIO;
+	if (ndev->hwerr_flags & NTB_HWERR_BAR_ALIGN) {
+		idx_reg = ndev->xlat_reg->bar2_idx + (idx * 0x2);
+		iowrite16(base_idx, mmio + idx_reg);
+		reg_val16 = ioread16(mmio + idx_reg);
+		if (reg_val16 != base_idx) {
+			iowrite64(base, mmio + limit_reg);
+			iowrite64(0, mmio + xlat_reg);
+			iowrite16(0, mmio + idx_reg);
+			return -EIO;
+		}
+		dev_dbg(&ntb->pdev->dev, "BAR %d IMBASEIDX: %#x\n", bar, reg_val16);
 	}
 
-	dev_dbg(&ntb->pdev->dev, "BAR %d IMBASEIDX: %#x\n", bar, reg_val16);
 
 	return 0;
 }
@@ -471,9 +481,51 @@ int intel_ntb4_link_disable(struct ntb_dev *ntb)
 	return 0;
 }
 
+static int intel_ntb4_mw_get_align(struct ntb_dev *ntb, int pidx, int idx,
+				   resource_size_t *addr_align,
+				   resource_size_t *size_align,
+				   resource_size_t *size_max)
+{
+	struct intel_ntb_dev *ndev = ntb_ndev(ntb);
+	resource_size_t bar_size, mw_size;
+	int bar;
+
+	if (pidx != NTB_DEF_PEER_IDX)
+		return -EINVAL;
+
+	if (idx >= ndev->b2b_idx && !ndev->b2b_off)
+		idx += 1;
+
+	bar = ndev_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	bar_size = pci_resource_len(ndev->ntb.pdev, bar);
+
+	if (idx == ndev->b2b_idx)
+		mw_size = bar_size - ndev->b2b_off;
+	else
+		mw_size = bar_size;
+
+	if (addr_align) {
+		if (ndev->hwerr_flags & NTB_HWERR_BAR_ALIGN)
+			*addr_align = pci_resource_len(ndev->ntb.pdev, bar);
+		else
+			*addr_align = PAGE_SIZE;
+	}
+
+	if (size_align)
+		*size_align = 1;
+
+	if (size_max)
+		*size_max = mw_size;
+
+	return 0;
+}
+
 const struct ntb_dev_ops intel_ntb4_ops = {
 	.mw_count		= intel_ntb_mw_count,
-	.mw_get_align		= intel_ntb_mw_get_align,
+	.mw_get_align		= intel_ntb4_mw_get_align,
 	.mw_set_trans		= intel_ntb4_mw_set_trans,
 	.peer_mw_count		= intel_ntb_peer_mw_count,
 	.peer_mw_get_addr	= intel_ntb_peer_mw_get_addr,

drivers/ntb/hw/intel/ntb_hw_gen4.h

@@ -5,6 +5,10 @@
 
 #include "ntb_hw_intel.h"
 
+/* Supported PCI device revision range for ICX */
+#define PCI_DEVICE_REVISION_ICX_MIN	0x2
+#define PCI_DEVICE_REVISION_ICX_MAX	0xF
+
 /* Intel Gen4 NTB hardware */
 /* PCIe config space */
 #define GEN4_IMBAR23SZ_OFFSET		0x00c4
@@ -84,4 +88,13 @@ ssize_t ndev_ntb4_debugfs_read(struct file *filp, char __user *ubuf,
 
 extern const struct ntb_dev_ops intel_ntb4_ops;
 
+static inline int pdev_is_ICX(struct pci_dev *pdev)
+{
+	if (pdev_is_gen4(pdev) &&
+	    pdev->revision >= PCI_DEVICE_REVISION_ICX_MIN &&
+	    pdev->revision <= PCI_DEVICE_REVISION_ICX_MAX)
+		return 1;
+	return 0;
+}
+
 #endif