northbridge/amd/amdht: Add isochronous setup support

The coherent fabric on all Family 10h/15h devices supports
isochronous mode, which is required for IOMMU operation.

Add initial support for isochronous operation.

Change-Id: Idd7c9b94a65f856b0059e1d45f8719d9475771b6
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/12042
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

4 files changed, 68 insertions, 4 deletions

diff --git a/src/northbridge/amd/amdht/h3ffeat.h b/src/northbridge/amd/amdht/h3ffeat.h
index 628b86e660..bcd4c10cd2 100644
--- a/src/northbridge/amd/amdht/h3ffeat.h
+++ b/src/northbridge/amd/amdht/h3ffeat.h
@@ -75,6 +75,7 @@
 #define HTSLAVE_LINK01_OFFSET			4
 #define HTSLAVE_LINK_CONTROL_0_REG		4
 #define HTSLAVE_FREQ_REV_0_REG			0xC
+#define HTSLAVE_FEATURE_CAP_REG		0x10
 
 /* HT3 gen Capability */
 #define IS_HT_GEN3_CAPABILITY(reg) \
@@ -122,10 +123,12 @@ typedef struct
 	u8 SelWidthIn;
 	u8 SelWidthOut;
 	u8 SelFrequency;
+	uint8_t enable_isochronous_mode;
 
 	/* This section is for keeping track of capabilities and possible configurations */
 	BOOL RegangCap;
 	uint32_t PrvFrequencyCap;
+	uint32_t PrvFeatureCap;
 	u8 PrvWidthInCap;
 	u8 PrvWidthOutCap;
 	uint32_t CompositeFrequencyCap;
diff --git a/src/northbridge/amd/amdht/h3finit.c b/src/northbridge/amd/amdht/h3finit.c
index e4ce76803a..6a45f10306 100644
--- a/src/northbridge/amd/amdht/h3finit.c
+++ b/src/northbridge/amd/amdht/h3finit.c
@@ -1415,6 +1415,38 @@ static void regangLinks(sMainData *pDat)
 #endif /* HT_BUILD_NC_ONLY */
 }
 
+static void detectIoLinkIsochronousCapable(sMainData *pDat)
+{
+	uint8_t i;
+	unsigned char iommu;
+	uint8_t isochronous_capable = 0;
+
+	iommu = 1;
+	get_option(&iommu, "iommu");
+
+	for (i = 0; i < pDat->TotalLinks*2; i += 2) {
+		if ((pDat->PortList[i].Type == PORTLIST_TYPE_CPU) && (pDat->PortList[i+1].Type == PORTLIST_TYPE_IO)) {
+			if ((pDat->PortList[i].PrvFeatureCap & 0x1) && (pDat->PortList[i+1].PrvFeatureCap & 0x1)) {
+				pDat->PortList[i].enable_isochronous_mode = 1;
+				pDat->PortList[i+1].enable_isochronous_mode = 1;
+				isochronous_capable = 1;
+			} else {
+				pDat->PortList[i].enable_isochronous_mode = 0;
+				pDat->PortList[i+1].enable_isochronous_mode = 0;
+			}
+		}
+	}
+
+	if (isochronous_capable && iommu) {
+		printk(BIOS_DEBUG, "Forcing HT links to isochronous mode due to enabled IOMMU\n");
+		/* Isochronous mode must be set on all links if the IOMMU is enabled */
+		for (i = 0; i < pDat->TotalLinks*2; i += 2) {
+			pDat->PortList[i].enable_isochronous_mode = 1;
+			pDat->PortList[i+1].enable_isochronous_mode = 1;
+		}
+	}
+}
+
 /*----------------------------------------------------------------------------------------
  * void
  * selectOptimalWidthAndFrequency(sMainData *pDat)
@@ -1535,7 +1567,6 @@ static void selectOptimalWidthAndFrequency(sMainData *pDat)
 			temp = cbPCBBAUpstreamWidth;
 		pDat->PortList[i].SelWidthIn = (u8)temp;
 		pDat->PortList[i+1].SelWidthOut = (u8)temp;
-
 	}
 }
 
@@ -1697,6 +1728,8 @@ static void linkOptimization(sMainData *pDat)
 {
 	pDat->nb->gatherLinkData(pDat, pDat->nb);
 	regangLinks(pDat);
+	if (is_fam15h())
+		detectIoLinkIsochronousCapable(pDat);
 	selectOptimalWidthAndFrequency(pDat);
 	hammerSublinkFixup(pDat);
 	pDat->nb->setLinkData(pDat, pDat->nb);
diff --git a/src/northbridge/amd/amdht/h3finit.h b/src/northbridge/amd/amdht/h3finit.h
index 1bd8616ef2..ab2dace20c 100644
--- a/src/northbridge/amd/amdht/h3finit.h
+++ b/src/northbridge/amd/amdht/h3finit.h
@@ -227,6 +227,7 @@ typedef struct {
 	 *	@param[in,out] u8*  LinkWidthIn  = modify to change the Link Witdh In
 	 *	@param[in,out] u8*  LinkWidthOut  = modify to change the Link Witdh Out
 	 *	@param[in,out] u32* FreqCap = modify to change the link's frequency capability
+	 *	@param[in,out] u32* FeatureCap = modify to change the link's feature capability
 	 *
 	 * ---------------------------------------------------------------------------------------
 	 */
@@ -241,7 +242,8 @@ typedef struct {
 		u8 Link,
 		u8 *LinkWidthIn,
 		u8 *LinkWidthOut,
-		u32 *FreqCap
+		u32 *FreqCap,
+		u32 *FeatureCap
 	);
 
 	/**----------------------------------------------------------------------------------------
diff --git a/src/northbridge/amd/amdht/h3ncmn.c b/src/northbridge/amd/amdht/h3ncmn.c
index c97d59293f..7937c6ea1a 100644
--- a/src/northbridge/amd/amdht/h3ncmn.c
+++ b/src/northbridge/amd/amdht/h3ncmn.c
@@ -1429,12 +1429,15 @@ static void gatherLinkData(sMainData *pDat, cNorthBridge *nb)
 				temp &= 0x7;	/* Mask off reserved values */
 				pDat->PortList[i].PrvFrequencyCap |= (temp << 17);
 			}
+
+			AmdPCIReadBits(linkBase + HTHOST_FEATURE_CAP_REG, 9, 0, &temp);
+			pDat->PortList[i].PrvFeatureCap = (u16)temp;
 		}
 		else
 		{
 			linkBase = pDat->PortList[i].Pointer;
 			if (pDat->PortList[i].Link == 1)
-			 linkBase += HTSLAVE_LINK01_OFFSET;
+				linkBase += HTSLAVE_LINK01_OFFSET;
 
 			AmdPCIReadBits(linkBase + HTSLAVE_LINK_CONTROL_0_REG, 22, 20, &temp);
 			pDat->PortList[i].PrvWidthOutCap = convertBitsToWidth((u8)temp, pDat->nb);
@@ -1445,6 +1448,9 @@ static void gatherLinkData(sMainData *pDat, cNorthBridge *nb)
 			AmdPCIReadBits(linkBase + HTSLAVE_FREQ_REV_0_REG, 31, 16, &temp);
 			pDat->PortList[i].PrvFrequencyCap = (u16)temp;
 
+			AmdPCIReadBits(linkBase + HTSLAVE_FEATURE_CAP_REG, 7, 0, &temp);
+			pDat->PortList[i].PrvFeatureCap = (u16)temp;
+
 			if (pDat->HtBlock->AMD_CB_DeviceCapOverride)
 			{
 				linkBase &= 0xFFFFF000;
@@ -1461,7 +1467,8 @@ static void gatherLinkData(sMainData *pDat, cNorthBridge *nb)
 					pDat->PortList[i].Link,
 					&(pDat->PortList[i].PrvWidthInCap),
 					&(pDat->PortList[i].PrvWidthOutCap),
-					&(pDat->PortList[i].PrvFrequencyCap));
+					&(pDat->PortList[i].PrvFrequencyCap),
+					&(pDat->PortList[i].PrvFeatureCap));
 			}
 		}
 	}
@@ -1562,6 +1569,16 @@ static void setLinkData(sMainData *pDat, cNorthBridge *nb)
 			if (is_gt_rev_d())
 				AmdPCIWriteBits(linkBase + HTHOST_FREQ_REV_REG_2, 0, 0, &temp2);
 			AmdPCIWriteBits(linkBase + HTHOST_FREQ_REV_REG, 11, 8, &temp);
+
+			/* Enable isochronous flow control mode if supported by chipset */
+			if (is_fam15h()) {
+				if (pDat->PortList[i].enable_isochronous_mode)
+					temp = 1;
+				else
+					temp = 0;
+				setHtControlRegisterBits(linkBase + HTHOST_LINK_CONTROL_REG, 12, 12, &temp);
+			}
+
 			if (frequency_index > HT_FREQUENCY_1000M) /*  Gen1 = 200MHz -> 1000MHz, Gen3 = 1200MHz -> 3200MHz */
 			{
 				/* Enable  for Gen3 frequencies */
@@ -1579,6 +1596,7 @@ static void setLinkData(sMainData *pDat, cNorthBridge *nb)
 						CPU_HTNB_FUNC_00,
 						REG_HT_LINK_RETRY0_0X130 + 4*pDat->PortList[i].Link),
 						0, 0, &temp);
+
 			/* and Scrambling enable / disable */
 			AmdPCIWriteBits(MAKE_SBDFO(makePCISegmentFromNode(pDat->PortList[i].NodeID),
 					makePCIBusFromNode(pDat->PortList[i].NodeID),
@@ -1617,6 +1635,14 @@ static void setLinkData(sMainData *pDat, cNorthBridge *nb)
 				bits = 0;
 			}
 
+			/* Enable isochronous flow control mode if supported by chipset */
+			if (is_fam15h()) {
+				if (pDat->PortList[i].enable_isochronous_mode)
+					temp = 1;
+				else
+					temp = 0;
+			}
+
 			/* Retry Enable */
 			isFound = FALSE;
 			currentPtr = linkBase & (u32)0xFFFFF000; /* Set PCI Offset to 0 */