Merge branch 'pci/crs'

- Wait for device readiness after reset by polling Vendor ID and looking
  for Configuration RRS instead of polling the Command register and looking
  for non-error completions (Bjorn Helgaas)

- Fix an aardvark issue with emulating Configuration RRS for two-byte reads
  of Vendor ID; previously it only worked for four-byte reads (Bjorn
  Helgaas)

- Rename CRS Completion Status to RRS to match spec usage (Bjorn Helgaas)

* pci/crs:
  PCI: Rename CRS Completion Status to RRS
  PCI: aardvark: Correct Configuration RRS checking
  PCI: Wait for device readiness with Configuration RRS

Author: bjorn-helgaas

drivers/bcma/driver_pci_host.c

@@ -334,7 +334,7 @@ static u8 bcma_find_pci_capability(struct bcma_drv_pci *pc, unsigned int dev,
 }
 
 /* If the root port is capable of returning Config Request
- * Retry Status (CRS) Completion Status to software then
+ * Retry Status (RRS) Completion Status to software then
  * enable the feature.
  */
 static void bcma_core_pci_enable_crs(struct bcma_drv_pci *pc)
@@ -348,10 +348,10 @@ static void bcma_core_pci_enable_crs(struct bcma_drv_pci *pc)
 					   NULL);
 	root_cap = cap_ptr + PCI_EXP_RTCAP;
 	bcma_extpci_read_config(pc, 0, 0, root_cap, &val16, sizeof(u16));
-	if (val16 & BCMA_CORE_PCI_RC_CRS_VISIBILITY) {
-		/* Enable CRS software visibility */
+	if (val16 & BCMA_CORE_PCI_RC_RRS_VISIBILITY) {
+		/* Enable Configuration RRS Software Visibility */
 		root_ctrl = cap_ptr + PCI_EXP_RTCTL;
-		val16 = PCI_EXP_RTCTL_CRSSVE;
+		val16 = PCI_EXP_RTCTL_RRS_SVE;
 		bcma_extpci_read_config(pc, 0, 0, root_ctrl, &val16,
 					sizeof(u16));
 
@@ -360,7 +360,7 @@ static void bcma_core_pci_enable_crs(struct bcma_drv_pci *pc)
 		 * 100 ms wait time from the end of Reset. If the device is
 		 * not done with its internal initialization, it must at
 		 * least return a completion TLP, with a completion status
-		 * of "Configuration Request Retry Status (CRS)". The root
+		 * of "Configuration Request Retry Status (RRS)". The root
 		 * complex must complete the request to the host by returning
 		 * a read-data value of 0001h for the Vendor ID field and
 		 * all 1s for any additional bytes included in the request.

drivers/pci/controller/dwc/pcie-tegra194.c

@@ -183,11 +183,11 @@
 #define GEN3_EQ_CONTROL_OFF_FB_MODE_MASK	GENMASK(3, 0)
 
 #define PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT	0x8D0
-#define AMBA_ERROR_RESPONSE_CRS_SHIFT		3
-#define AMBA_ERROR_RESPONSE_CRS_MASK		GENMASK(1, 0)
-#define AMBA_ERROR_RESPONSE_CRS_OKAY		0
-#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFFFFFF	1
-#define AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001	2
+#define AMBA_ERROR_RESPONSE_RRS_SHIFT		3
+#define AMBA_ERROR_RESPONSE_RRS_MASK		GENMASK(1, 0)
+#define AMBA_ERROR_RESPONSE_RRS_OKAY		0
+#define AMBA_ERROR_RESPONSE_RRS_OKAY_FFFFFFFF	1
+#define AMBA_ERROR_RESPONSE_RRS_OKAY_FFFF0001	2
 
 #define MSIX_ADDR_MATCH_LOW_OFF			0x940
 #define MSIX_ADDR_MATCH_LOW_OFF_EN		BIT(0)
@@ -907,11 +907,11 @@ static int tegra_pcie_dw_host_init(struct dw_pcie_rp *pp)
 
 	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
 
-	/* Enable as 0xFFFF0001 response for CRS */
+	/* Enable as 0xFFFF0001 response for RRS */
 	val = dw_pcie_readl_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT);
-	val &= ~(AMBA_ERROR_RESPONSE_CRS_MASK << AMBA_ERROR_RESPONSE_CRS_SHIFT);
-	val |= (AMBA_ERROR_RESPONSE_CRS_OKAY_FFFF0001 <<
-		AMBA_ERROR_RESPONSE_CRS_SHIFT);
+	val &= ~(AMBA_ERROR_RESPONSE_RRS_MASK << AMBA_ERROR_RESPONSE_RRS_SHIFT);
+	val |= (AMBA_ERROR_RESPONSE_RRS_OKAY_FFFF0001 <<
+		AMBA_ERROR_RESPONSE_RRS_SHIFT);
 	dw_pcie_writel_dbi(pci, PORT_LOGIC_AMBA_ERROR_RESPONSE_DEFAULT, val);
 
 	/* Clear Slot Clock Configuration bit if SRNS configuration */

drivers/pci/controller/pci-aardvark.c

@@ -50,7 +50,7 @@
 #define   PIO_COMPLETION_STATUS_MASK		GENMASK(9, 7)
 #define   PIO_COMPLETION_STATUS_OK		0
 #define   PIO_COMPLETION_STATUS_UR		1
-#define   PIO_COMPLETION_STATUS_CRS		2
+#define   PIO_COMPLETION_STATUS_RRS		2
 #define   PIO_COMPLETION_STATUS_CA		4
 #define   PIO_NON_POSTED_REQ			BIT(10)
 #define   PIO_ERR_STATUS			BIT(11)
@@ -262,7 +262,7 @@ enum {
 
 #define MSI_IRQ_NUM			32
 
-#define CFG_RD_CRS_VAL			0xffff0001
+#define CFG_RD_RRS_VAL			0xffff0001
 
 struct advk_pcie {
 	struct platform_device *pdev;
@@ -649,7 +649,7 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
 	advk_pcie_train_link(pcie);
 }
 
-static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u32 *val)
+static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_rrs, u32 *val)
 {
 	struct device *dev = &pcie->pdev->dev;
 	u32 reg;
@@ -669,7 +669,7 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3
 	 * 2) value Unsupported Request(1) of COMPLETION_STATUS(bit9:7) only
 	 *    means a PIO write error, and for PIO read it is successful with
 	 *    a read value of 0xFFFFFFFF.
-	 * 3) value Completion Retry Status(CRS) of COMPLETION_STATUS(bit9:7)
+	 * 3) value Config Request Retry Status(RRS) of COMPLETION_STATUS(bit9:7)
 	 *    only means a PIO write error, and for PIO read it is successful
 	 *    with a read value of 0xFFFF0001.
 	 * 4) value Completer Abort (CA) of COMPLETION_STATUS(bit9:7) means
@@ -694,10 +694,10 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3
 		strcomp_status = "UR";
 		ret = -EOPNOTSUPP;
 		break;
-	case PIO_COMPLETION_STATUS_CRS:
-		if (allow_crs && val) {
-			/* PCIe r4.0, sec 2.3.2, says:
-			 * If CRS Software Visibility is enabled:
+	case PIO_COMPLETION_STATUS_RRS:
+		if (allow_rrs && val) {
+			/* PCIe r6.0, sec 2.3.2, says:
+			 * If Configuration RRS Software Visibility is enabled:
 			 * For a Configuration Read Request that includes both
 			 * bytes of the Vendor ID field of a device Function's
 			 * Configuration Space Header, the Root Complex must
@@ -706,30 +706,30 @@ static int advk_pcie_check_pio_status(struct advk_pcie *pcie, bool allow_crs, u3
 			 * all '1's for any additional bytes included in the
 			 * request.
 			 *
-			 * So CRS in this case is not an error status.
+			 * So RRS in this case is not an error status.
 			 */
-			*val = CFG_RD_CRS_VAL;
+			*val = CFG_RD_RRS_VAL;
 			strcomp_status = NULL;
 			ret = 0;
 			break;
 		}
-		/* PCIe r4.0, sec 2.3.2, says:
-		 * If CRS Software Visibility is not enabled, the Root Complex
+		/* PCIe r6.0, sec 2.3.2, says:
+		 * If RRS Software Visibility is not enabled, the Root Complex
 		 * must re-issue the Configuration Request as a new Request.
-		 * If CRS Software Visibility is enabled: For a Configuration
+		 * If RRS Software Visibility is enabled: For a Configuration
 		 * Write Request or for any other Configuration Read Request,
 		 * the Root Complex must re-issue the Configuration Request as
 		 * a new Request.
 		 * A Root Complex implementation may choose to limit the number
-		 * of Configuration Request/CRS Completion Status loops before
+		 * of Configuration Request/RRS Completion Status loops before
 		 * determining that something is wrong with the target of the
 		 * Request and taking appropriate action, e.g., complete the
 		 * Request to the host as a failed transaction.
 		 *
 		 * So return -EAGAIN and caller (pci-aardvark.c driver) will
 		 * re-issue request again up to the PIO_RETRY_CNT retries.
 		 */
-		strcomp_status = "CRS";
+		strcomp_status = "RRS";
 		ret = -EAGAIN;
 		break;
 	case PIO_COMPLETION_STATUS_CA:
@@ -920,8 +920,8 @@ advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
 
 	case PCI_EXP_RTCTL: {
 		u16 rootctl = le16_to_cpu(bridge->pcie_conf.rootctl);
-		/* Only emulation of PMEIE and CRSSVE bits is provided */
-		rootctl &= PCI_EXP_RTCTL_PMEIE | PCI_EXP_RTCTL_CRSSVE;
+		/* Only emulation of PMEIE and RRS_SVE bits is provided */
+		rootctl &= PCI_EXP_RTCTL_PMEIE | PCI_EXP_RTCTL_RRS_SVE;
 		bridge->pcie_conf.rootctl = cpu_to_le16(rootctl);
 		break;
 	}
@@ -1075,7 +1075,7 @@ static int advk_sw_pci_bridge_init(struct advk_pcie *pcie)
 	bridge->pcie_conf.slotsta = cpu_to_le16(PCI_EXP_SLTSTA_PDS);
 
 	/* Indicates supports for Completion Retry Status */
-	bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_CRSVIS);
+	bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_RRS_SV);
 
 	bridge->subsystem_vendor_id = advk_readl(pcie, PCIE_CORE_SSDEV_ID_REG) & 0xffff;
 	bridge->subsystem_id = advk_readl(pcie, PCIE_CORE_SSDEV_ID_REG) >> 16;
@@ -1141,7 +1141,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 {
 	struct advk_pcie *pcie = bus->sysdata;
 	int retry_count;
-	bool allow_crs;
+	bool allow_rrs;
 	u32 reg;
 	int ret;
 
@@ -1153,16 +1153,16 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 						 size, val);
 
 	/*
-	 * Completion Retry Status is possible to return only when reading all
-	 * 4 bytes from PCI_VENDOR_ID and PCI_DEVICE_ID registers at once and
-	 * CRSSVE flag on Root Bridge is enabled.
+	 * Configuration Request Retry Status (RRS) is possible to return
+	 * only when reading both bytes from PCI_VENDOR_ID at once and
+	 * RRS_SVE flag on Root Port is enabled.
 	 */
-	allow_crs = (where == PCI_VENDOR_ID) && (size == 4) &&
+	allow_rrs = (where == PCI_VENDOR_ID) && (size >= 2) &&
 		    (le16_to_cpu(pcie->bridge.pcie_conf.rootctl) &
-		     PCI_EXP_RTCTL_CRSSVE);
+		     PCI_EXP_RTCTL_RRS_SVE);
 
 	if (advk_pcie_pio_is_running(pcie))
-		goto try_crs;
+		goto try_rrs;
 
 	/* Program the control register */
 	reg = advk_readl(pcie, PIO_CTRL);
@@ -1189,12 +1189,12 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 
 		ret = advk_pcie_wait_pio(pcie);
 		if (ret < 0)
-			goto try_crs;
+			goto try_rrs;
 
 		retry_count += ret;
 
 		/* Check PIO status and get the read result */
-		ret = advk_pcie_check_pio_status(pcie, allow_crs, val);
+		ret = advk_pcie_check_pio_status(pcie, allow_rrs, val);
 	} while (ret == -EAGAIN && retry_count < PIO_RETRY_CNT);
 
 	if (ret < 0)
@@ -1207,13 +1207,13 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 
 	return PCIBIOS_SUCCESSFUL;
 
-try_crs:
+try_rrs:
 	/*
-	 * If it is possible, return Completion Retry Status so that caller
-	 * tries to issue the request again instead of failing.
+	 * If it is possible, return Configuration Request Retry Status so
+	 * that caller tries to issue the request again instead of failing.
 	 */
-	if (allow_crs) {
-		*val = CFG_RD_CRS_VAL;
+	if (allow_rrs) {
+		*val = CFG_RD_RRS_VAL;
 		return PCIBIOS_SUCCESSFUL;
 	}
 

drivers/pci/controller/pci-xgene.c

@@ -171,17 +171,17 @@ static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
 
 	/*
 	 * The v1 controller has a bug in its Configuration Request Retry
-	 * Status (CRS) logic: when CRS Software Visibility is enabled and
+	 * Status (RRS) logic: when RRS Software Visibility is enabled and
 	 * we read the Vendor and Device ID of a non-existent device, the
 	 * controller fabricates return data of 0xFFFF0001 ("device exists
 	 * but is not ready") instead of 0xFFFFFFFF (PCI_ERROR_RESPONSE)
 	 * ("device does not exist").  This causes the PCI core to retry
 	 * the read until it times out.  Avoid this by not claiming to
-	 * support CRS SV.
+	 * support RRS SV.
 	 */
 	if (pci_is_root_bus(bus) && (port->version == XGENE_PCIE_IP_VER_1) &&
 	    ((where & ~0x3) == XGENE_V1_PCI_EXP_CAP + PCI_EXP_RTCTL))
-		*val &= ~(PCI_EXP_RTCAP_CRSVIS << 16);
+		*val &= ~(PCI_EXP_RTCAP_RRS_SV << 16);
 
 	if (size <= 2)
 		*val = (*val >> (8 * (where & 3))) & ((1 << (size * 8)) - 1);

drivers/pci/controller/pcie-iproc.c

@@ -54,7 +54,7 @@
 
 #define CFG_RD_SUCCESS			0
 #define CFG_RD_UR			1
-#define CFG_RD_CRS			2
+#define CFG_RD_RRS			2
 #define CFG_RD_CA			3
 #define CFG_RETRY_STATUS		0xffff0001
 #define CFG_RETRY_STATUS_TIMEOUT_US	500000 /* 500 milliseconds */
@@ -485,31 +485,31 @@ static unsigned int iproc_pcie_cfg_retry(struct iproc_pcie *pcie,
 	u32 status;
 
 	/*
-	 * As per PCIe spec r3.1, sec 2.3.2, CRS Software Visibility only
+	 * As per PCIe r6.0, sec 2.3.2, Config RRS Software Visibility only
 	 * affects config reads of the Vendor ID.  For config writes or any
 	 * other config reads, the Root may automatically reissue the
 	 * configuration request again as a new request.
 	 *
 	 * For config reads, this hardware returns CFG_RETRY_STATUS data
-	 * when it receives a CRS completion, regardless of the address of
-	 * the read or the CRS Software Visibility Enable bit.  As a
+	 * when it receives a RRS completion, regardless of the address of
+	 * the read or the RRS Software Visibility Enable bit.  As a
 	 * partial workaround for this, we retry in software any read that
 	 * returns CFG_RETRY_STATUS.
 	 *
 	 * Note that a non-Vendor ID config register may have a value of
 	 * CFG_RETRY_STATUS.  If we read that, we can't distinguish it from
-	 * a CRS completion, so we will incorrectly retry the read and
+	 * a RRS completion, so we will incorrectly retry the read and
 	 * eventually return the wrong data (0xffffffff).
 	 */
 	data = readl(cfg_data_p);
 	while (data == CFG_RETRY_STATUS && timeout--) {
 		/*
-		 * CRS state is set in CFG_RD status register
+		 * RRS state is set in CFG_RD status register
 		 * This will handle the case where CFG_RETRY_STATUS is
 		 * valid config data.
 		 */
 		status = iproc_pcie_read_reg(pcie, IPROC_PCIE_CFG_RD_STATUS);
-		if (status != CFG_RD_CRS)
+		if (status != CFG_RD_RRS)
 			return data;
 
 		udelay(1);
@@ -556,8 +556,8 @@ static void iproc_pcie_fix_cap(struct iproc_pcie *pcie, int where, u32 *val)
 		break;
 
 	case IPROC_PCI_EXP_CAP + PCI_EXP_RTCTL:
-		/* Don't advertise CRS SV support */
-		*val &= ~(PCI_EXP_RTCAP_CRSVIS << 16);
+		/* Don't advertise RRS SV support */
+		*val &= ~(PCI_EXP_RTCAP_RRS_SV << 16);
 		break;
 
 	default:

drivers/pci/pci-bridge-emul.c

@@ -257,8 +257,8 @@ struct pci_bridge_reg_behavior pcie_cap_regs_behavior[PCI_CAP_PCIE_SIZEOF / 4] =
 		 */
 		.rw = (PCI_EXP_RTCTL_SECEE | PCI_EXP_RTCTL_SENFEE |
 		       PCI_EXP_RTCTL_SEFEE | PCI_EXP_RTCTL_PMEIE |
-		       PCI_EXP_RTCTL_CRSSVE),
-		.ro = PCI_EXP_RTCAP_CRSVIS << 16,
+		       PCI_EXP_RTCTL_RRS_SVE),
+		.ro = PCI_EXP_RTCAP_RRS_SV << 16,
 	},
 
 	[PCI_EXP_RTSTA / 4] = {

drivers/pci/pci.c

@@ -1283,7 +1283,9 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 {
 	int delay = 1;
 	bool retrain = false;
-	struct pci_dev *bridge;
+	struct pci_dev *root, *bridge;
+
+	root = pcie_find_root_port(dev);
 
 	if (pci_is_pcie(dev)) {
 		bridge = pci_upstream_bridge(dev);
@@ -1292,16 +1294,23 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 	}
 
 	/*
-	 * After reset, the device should not silently discard config
-	 * requests, but it may still indicate that it needs more time by
-	 * responding to them with CRS completions.  The Root Port will
-	 * generally synthesize ~0 (PCI_ERROR_RESPONSE) data to complete
-	 * the read (except when CRS SV is enabled and the read was for the
-	 * Vendor ID; in that case it synthesizes 0x0001 data).
+	 * The caller has already waited long enough after a reset that the
+	 * device should respond to config requests, but it may respond
+	 * with Request Retry Status (RRS) if it needs more time to
+	 * initialize.
+	 *
+	 * If the device is below a Root Port with Configuration RRS
+	 * Software Visibility enabled, reading the Vendor ID returns a
+	 * special data value if the device responded with RRS.  Read the
+	 * Vendor ID until we get non-RRS status.
 	 *
-	 * Wait for the device to return a non-CRS completion.  Read the
-	 * Command register instead of Vendor ID so we don't have to
-	 * contend with the CRS SV value.
+	 * If there's no Root Port or Configuration RRS Software Visibility
+	 * is not enabled, the device may still respond with RRS, but
+	 * hardware may retry the config request.  If no retries receive
+	 * Successful Completion, hardware generally synthesizes ~0
+	 * (PCI_ERROR_RESPONSE) data to complete the read.  Reading Vendor
+	 * ID for VFs and non-existent devices also returns ~0, so read the
+	 * Command register until it returns something other than ~0.
 	 */
 	for (;;) {
 		u32 id;
@@ -1311,9 +1320,15 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout)
 			return -ENOTTY;
 		}
 
-		pci_read_config_dword(dev, PCI_COMMAND, &id);
-		if (!PCI_POSSIBLE_ERROR(id))
-			break;
+		if (root && root->config_rrs_sv) {
+			pci_read_config_dword(dev, PCI_VENDOR_ID, &id);
+			if (!pci_bus_rrs_vendor_id(id))
+				break;
+		} else {
+			pci_read_config_dword(dev, PCI_COMMAND, &id);
+			if (!PCI_POSSIBLE_ERROR(id))
+				break;
+		}
 
 		if (delay > timeout) {
 			pci_warn(dev, "not ready %dms after %s; giving up\n",