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From: "Pali Rohár" <pali@kernel.org>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Rob Herring <robh@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: "Russell King" <rmk+kernel@armlinux.org.uk>,
	"Marek Behún" <kabel@kernel.org>,
	"Remi Pommarel" <repk@triplefau.lt>, Xogium <contact@xogium.me>,
	"Tomasz Maciej Nowak" <tmn505@gmail.com>,
	"Marc Zyngier" <maz@kernel.org>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 03/42] PCI: aardvark: Fix checking for PIO status
Date: Thu,  6 May 2021 17:31:14 +0200	[thread overview]
Message-ID: <20210506153153.30454-4-pali@kernel.org> (raw)
In-Reply-To: <20210506153153.30454-1-pali@kernel.org>

From: Evan Wang <xswang@marvell.com>

There is an issue that when PCIe switch is connected to an Armada 3700
board, there will be lots of warnings about PIO errors when reading the
config space. According to Aardvark PIO read and write sequence in HW
specification, the current way to check PIO status has the following
issues:

1) For PIO read operation, it reports the error message, which should be
   avoided according to HW specification.

2) For PIO read and write operations, it only checks PIO operation complete
   status, which is not enough, and error status should also be checked.

This patch aligns the code with Aardvark PIO read and write sequence in HW
specification on PIO status check and fix the warnings when reading config
space.

This patch also returns Completion Retry Status value when the read request
timeout, to give the caller a chance to send the request again instead of
failing.

Signed-off-by: Evan Wang <xswang@marvell.com>
Reviewed-by: Victor Gu <xigu@marvell.com>
Tested-by: Victor Gu <xigu@marvell.com>
[pali: Return CRS also after timeout]
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Cc: stable@vger.kernel.org # b1bd5714472c ("PCI: aardvark: Indicate error in 'val' when config read fails")
---
 drivers/pci/controller/pci-aardvark.c | 93 +++++++++++++++++++++++----
 1 file changed, 80 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 2f8380a1f84f..a37ba86f1b2d 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -58,6 +58,7 @@
 #define   PIO_COMPLETION_STATUS_CRS		2
 #define   PIO_COMPLETION_STATUS_CA		4
 #define   PIO_NON_POSTED_REQ			BIT(10)
+#define   PIO_ERR_STATUS			BIT(11)
 #define PIO_ADDR_LS				(PIO_BASE_ADDR + 0x8)
 #define PIO_ADDR_MS				(PIO_BASE_ADDR + 0xc)
 #define PIO_WR_DATA				(PIO_BASE_ADDR + 0x10)
@@ -176,6 +177,9 @@
 
 #define MSI_IRQ_NUM			32
 
+#define CFG_RD_UR_VAL			0xffffffff
+#define CFG_RD_CRS_VAL			0xffff0001
+
 struct advk_pcie {
 	struct platform_device *pdev;
 	void __iomem *base;
@@ -461,7 +465,7 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
 	advk_writel(pcie, reg, PCIE_CORE_CMD_STATUS_REG);
 }
 
-static void advk_pcie_check_pio_status(struct advk_pcie *pcie)
+static int advk_pcie_check_pio_status(struct advk_pcie *pcie, u32 *val)
 {
 	struct device *dev = &pcie->pdev->dev;
 	u32 reg;
@@ -472,15 +476,50 @@ static void advk_pcie_check_pio_status(struct advk_pcie *pcie)
 	status = (reg & PIO_COMPLETION_STATUS_MASK) >>
 		PIO_COMPLETION_STATUS_SHIFT;
 
-	if (!status)
-		return;
-
+	/*
+	 * According to HW spec, the PIO status check sequence as below:
+	 * 1) even if COMPLETION_STATUS(bit9:7) indicates successful,
+	 *    it still needs to check Error Status(bit11), only when this bit
+	 *    indicates no error happen, the operation is successful.
+	 * 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)
+	 *    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
+	 *    error for both PIO read and PIO write operation.
+	 * 5) other errors are indicated as 'unknown'.
+	 */
 	switch (status) {
+	case PIO_COMPLETION_STATUS_OK:
+		if (reg & PIO_ERR_STATUS) {
+			strcomp_status = "COMP_ERR";
+			break;
+		}
+		/* Get the read result */
+		if (val)
+			*val = advk_readl(pcie, PIO_RD_DATA);
+		/* No error */
+		strcomp_status = NULL;
+		break;
 	case PIO_COMPLETION_STATUS_UR:
-		strcomp_status = "UR";
+		if (val) {
+			/* For reading, UR is not an error status */
+			*val = CFG_RD_UR_VAL;
+			strcomp_status = NULL;
+		} else {
+			strcomp_status = "UR";
+		}
 		break;
 	case PIO_COMPLETION_STATUS_CRS:
-		strcomp_status = "CRS";
+		if (val) {
+			/* For reading, CRS is not an error status */
+			*val = CFG_RD_CRS_VAL;
+			strcomp_status = NULL;
+		} else {
+			strcomp_status = "CRS";
+		}
 		break;
 	case PIO_COMPLETION_STATUS_CA:
 		strcomp_status = "CA";
@@ -490,6 +529,9 @@ static void advk_pcie_check_pio_status(struct advk_pcie *pcie)
 		break;
 	}
 
+	if (!strcomp_status)
+		return 0;
+
 	if (reg & PIO_NON_POSTED_REQ)
 		str_posted = "Non-posted";
 	else
@@ -497,6 +539,8 @@ static void advk_pcie_check_pio_status(struct advk_pcie *pcie)
 
 	dev_err(dev, "%s PIO Response Status: %s, %#x @ %#x\n",
 		str_posted, strcomp_status, reg, advk_readl(pcie, PIO_ADDR_LS));
+
+	return -EFAULT;
 }
 
 static int advk_pcie_wait_pio(struct advk_pcie *pcie)
@@ -703,8 +747,17 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 						 size, val);
 
 	if (advk_pcie_pio_is_running(pcie)) {
-		*val = 0xffffffff;
-		return PCIBIOS_SET_FAILED;
+		/*
+		 * For PCI_VENDOR_ID register, return Completion Retry Status
+		 * so caller tries to issue the request again insted of failing
+		 */
+		if (where == PCI_VENDOR_ID) {
+			*val = CFG_RD_CRS_VAL;
+			return PCIBIOS_SUCCESSFUL;
+		} else {
+			*val = 0xffffffff;
+			return PCIBIOS_SET_FAILED;
+		}
 	}
 
 	/* Program the control register */
@@ -729,15 +782,27 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
 	advk_writel(pcie, 1, PIO_START);
 
 	ret = advk_pcie_wait_pio(pcie);
+	if (ret < 0) {
+		/*
+		 * For PCI_VENDOR_ID register, return Completion Retry Status
+		 * so caller tries to issue the request again instead of failing
+		 */
+		if (where == PCI_VENDOR_ID) {
+			*val = CFG_RD_CRS_VAL;
+			return PCIBIOS_SUCCESSFUL;
+		} else {
+			*val = 0xffffffff;
+			return PCIBIOS_SET_FAILED;
+		}
+	}
+
+	/* Check PIO status and get the read result */
+	ret = advk_pcie_check_pio_status(pcie, val);
 	if (ret < 0) {
 		*val = 0xffffffff;
 		return PCIBIOS_SET_FAILED;
 	}
 
-	advk_pcie_check_pio_status(pcie);
-
-	/* Get the read result */
-	*val = advk_readl(pcie, PIO_RD_DATA);
 	if (size == 1)
 		*val = (*val >> (8 * (where & 3))) & 0xff;
 	else if (size == 2)
@@ -801,7 +866,9 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
 	if (ret < 0)
 		return PCIBIOS_SET_FAILED;
 
-	advk_pcie_check_pio_status(pcie);
+	ret = advk_pcie_check_pio_status(pcie, NULL);
+	if (ret < 0)
+		return PCIBIOS_SET_FAILED;
 
 	return PCIBIOS_SUCCESSFUL;
 }
-- 
2.20.1


  parent reply	other threads:[~2021-05-06 15:33 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-06 15:31 [PATCH 00/42] PCI: aardvark: Various driver fixes Pali Rohár
2021-05-06 15:31 ` [PATCH 01/42] PCI: aardvark: Fix kernel panic during PIO transfer Pali Rohár
2021-05-19  8:06   ` Pali Rohár
2021-05-06 15:31 ` [PATCH 02/42] PCI: aardvark: Fix checking for PIO Non-posted Request Pali Rohár
2021-05-06 15:31 ` Pali Rohár [this message]
2021-05-06 15:31 ` [PATCH 04/42] PCI: aardvark: Increase polling delay to 1.5s while waiting for PIO response Pali Rohár
2021-05-06 15:31 ` [PATCH 05/42] PCI: pci-bridge-emul: Add PCIe Root Capabilities Register Pali Rohár
2021-05-06 23:10   ` Bjorn Helgaas
2021-05-07 14:40     ` Pali Rohár
2021-05-07 16:41       ` Bjorn Helgaas
2021-05-06 15:31 ` [PATCH 06/42] PCI: aardvark: Fix reporting CRS Software Visibility on emulated bridge Pali Rohár
2021-05-07 13:03   ` Bjorn Helgaas
2021-05-07 15:25     ` Pali Rohár
2021-05-07 15:33     ` Pali Rohár
2021-05-06 15:31 ` [PATCH 07/42] PCI: aardvark: Fix link training Pali Rohár
2021-05-06 15:31 ` [PATCH 08/42] PCI: Add PCI_EXP_DEVCTL_PAYLOAD_* macros Pali Rohár
2021-05-06 15:31 ` [PATCH 09/42] PCI: aardvark: Fix PCIe Max Payload Size setting Pali Rohár
2021-05-06 15:31 ` [PATCH 10/42] PCI: aardvark: Implement workaround for the readback value of VEND_ID Pali Rohár
2021-05-06 15:31 ` [PATCH 11/42] PCI: aardvark: Do not touch status bits of masked interrupts in interrupt handler Pali Rohár
2021-05-06 15:31 ` [PATCH 12/42] PCI: aardvark: Check for virq mapping when processing INTx IRQ Pali Rohár
2021-05-07  9:15   ` Marc Zyngier
2021-06-04 16:24     ` Pali Rohár
2021-06-04 16:29       ` Marc Zyngier
2021-05-06 15:31 ` [PATCH 13/42] PCI: aardvark: Remove irq_mask_ack callback for INTx interrupts Pali Rohár
2021-05-07  9:16   ` Marc Zyngier
2021-05-06 15:31 ` [PATCH 14/42] PCI: aardvark: Don't mask irq when mapping Pali Rohár
2021-05-07  9:20   ` Marc Zyngier
2021-05-07  9:27     ` Pali Rohár
2021-05-06 15:31 ` [PATCH 15/42] PCI: aardvark: Change name of INTx irq_chip to advk-INT Pali Rohár
2021-05-07  9:08   ` Marc Zyngier
2021-05-24 14:36     ` Marek Behún
2021-05-24 15:14       ` Marc Zyngier
2021-05-06 15:31 ` [PATCH 16/42] PCI: aardvark: Remove unneeded goto Pali Rohár
2021-05-06 15:31 ` [PATCH 17/42] PCI: aardvark: Fix support for MSI interrupts Pali Rohár
2021-05-07 10:16   ` Marc Zyngier
2021-05-07 14:44     ` Pali Rohár
2021-05-07 16:24       ` Marc Zyngier
2021-06-04 16:02         ` Pali Rohár
2021-06-04 16:22           ` Marc Zyngier
2021-05-06 15:31 ` [PATCH 18/42] PCI: aardvark: Correctly clear and unmask all " Pali Rohár
2021-05-07 10:19   ` Marc Zyngier
2021-05-07 10:21     ` Pali Rohár
2021-05-06 15:31 ` [PATCH 19/42] PCI: aardvark: Fix setting MSI address Pali Rohár
2021-05-07 10:25   ` Marc Zyngier
2021-05-06 15:31 ` [PATCH 20/42] PCI: aardvark: Add support for more than 32 MSI interrupts Pali Rohár
2021-07-02 21:35   ` Pali Rohár
2021-05-06 15:31 ` [PATCH 21/42] PCI: aardvark: Add support for masking " Pali Rohár
2021-05-06 15:31 ` [PATCH 22/42] PCI: aardvark: Enable MSI-X support Pali Rohár
2021-05-06 15:31 ` [PATCH 23/42] PCI: aardvark: Fix support for ERR interrupt on emulated bridge Pali Rohár
2021-05-06 15:31 ` [PATCH 24/42] PCI: aardvark: Fix support for PME " Pali Rohár
2021-05-06 15:31 ` [PATCH 25/42] PCI: aardvark: Fix support for PME requester " Pali Rohár
2021-05-06 15:31 ` [PATCH 26/42] PCI: aardvark: Fix support for bus mastering and PCI_COMMAND " Pali Rohár
2021-05-06 15:31 ` [PATCH 27/42] PCI: aardvark: Disable bus mastering and mask all interrupts when unbinding driver Pali Rohár
2021-05-06 15:31 ` [PATCH 28/42] PCI: aardvark: Free config space for emulated root bridge when unbinding driver to fix memory leak Pali Rohár
2021-05-06 15:31 ` [PATCH 29/42] PCI: aardvark: Reset PCIe card and disable PHY when unbinding driver Pali Rohár
2021-05-06 15:31 ` [PATCH 30/42] PCI: aardvark: Rewrite irq code to chained irq handler Pali Rohár
2021-05-06 15:31 ` [PATCH 31/42] PCI: aardvark: Use separate INTA interrupt for emulated root bridge Pali Rohár
2021-05-06 15:31 ` [PATCH 32/42] PCI: pci-bridge-emul: Add description for class_revision field Pali Rohár
2021-05-06 15:31 ` [PATCH 33/42] PCI: pci-bridge-emul: Add definitions for missing capabilities registers Pali Rohár
2021-05-06 15:31 ` [PATCH 34/42] PCI: aardvark: Add support for DEVCAP2, DEVCTL2, LNKCAP2 and LNKCTL2 registers on emulated bridge Pali Rohár
2021-05-06 15:31 ` [PATCH 35/42] PCI: aardvark: Add support for PCI_BRIDGE_CTL_BUS_RESET " Pali Rohár
2021-05-06 15:31 ` [PATCH 36/42] PCI: aardvark: Replace custom PCIE_CORE_ERR_CAPCTL_* macros by linux/pci_regs.h macros Pali Rohár
2021-05-06 15:31 ` [PATCH 37/42] PCI: aardvark: Replace custom PCIE_CORE_INT_* macros by linux PCI_INTERRUPT_* values Pali Rohár
2021-05-06 15:31 ` [PATCH 38/42] PCI: aardvark: Cleanup some register macros Pali Rohár
2021-05-06 15:31 ` [PATCH 39/42] PCI: aardvark: Add comments for OB_WIN_ENABLE and ADDR_WIN_DISABLE Pali Rohár
2021-05-06 15:31 ` [PATCH 40/42] PCI: pci-bridge-emul: re-arrange register tests Pali Rohár
2021-05-06 15:31 ` [PATCH 41/42] PCI: pci-bridge-emul: add support for PCIe extended capabilities Pali Rohár
2021-05-06 15:31 ` [PATCH 42/42] PCI: aardvark: Add support for Advanced Error Reporting registers on emulated bridge Pali Rohár
2021-06-03 15:16 ` [PATCH 00/42] PCI: aardvark: Various driver fixes Lorenzo Pieralisi
2021-06-03 17:02   ` Pali Rohár
2021-06-03 18:02   ` Simon Glass
2021-06-03 18:18     ` Pali Rohár
2021-06-04 14:05     ` Lorenzo Pieralisi

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