diff options
Diffstat (limited to 'target/linux/mvebu')
| -rw-r--r-- | target/linux/mvebu/patches-5.15/100-aardvark-workaround-PCIe.patch | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/target/linux/mvebu/patches-5.15/100-aardvark-workaround-PCIe.patch b/target/linux/mvebu/patches-5.15/100-aardvark-workaround-PCIe.patch new file mode 100644 index 0000000000..975eadb80e --- /dev/null +++ b/target/linux/mvebu/patches-5.15/100-aardvark-workaround-PCIe.patch @@ -0,0 +1,81 @@ +Subject: [PATCH v2] PCI: aardvark: Implement workaround for PCIe Completion Timeout +Date: Tue, 2 Aug 2022 14:38:16 +0200 +Message-Id: <20220802123816.21817-1-pali@kernel.org> +X-Mailer: git-send-email 2.20.1 +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit +Precedence: bulk +List-ID: <linux-pci.vger.kernel.org> +X-Mailing-List: linux-pci@vger.kernel.org + +Marvell Armada 3700 Functional Errata, Guidelines, and Restrictions +document describes in erratum 3.12 PCIe Completion Timeout (Ref #: 251), +that PCIe IP does not support a strong-ordered model for inbound posted vs. +outbound completion. + +As a workaround for this erratum, DIS_ORD_CHK flag in Debug Mux Control +register must be set. It disables the ordering check in the core between +Completions and Posted requests received from the link. + +Marvell also suggests to do full memory barrier at the beginning of +aardvark summary interrupt handler before calling interrupt handlers of +endpoint drivers in order to minimize the risk for the race condition +documented in the Erratum between the DMA done status reading and the +completion of writing to the host memory. + +More details about this issue and suggested workarounds are in discussion: +https://lore.kernel.org/linux-pci/BN9PR18MB425154FE5019DCAF2028A1D5DB8D9@BN9PR18MB4251.namprd18.prod.outlook.com/t/#u + +It was reported that enabling this workaround fixes instability issues and +"Unhandled fault" errors when using 60 GHz WiFi 802.11ad card with Qualcomm +QCA6335 chip under significant load which were caused by interrupt status +stuck in the outbound CMPLT queue traced back to this erratum. + +This workaround fixes also kernel panic triggered after some minutes of +usage 5 GHz WiFi 802.11ax card with Mediatek MT7915 chip: + + Internal error: synchronous external abort: 96000210 [#1] SMP + Kernel panic - not syncing: Fatal exception in interrupt + +Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> +Signed-off-by: Pali Rohár <pali@kernel.org> +Fixes: 8c39d710363c ("PCI: aardvark: Add Aardvark PCI host controller driver") +Cc: stable@vger.kernel.org +--- + drivers/pci/controller/pci-aardvark.c | 10 ++++++++++ + 1 file changed, 10 insertions(+) + +--- a/drivers/pci/controller/pci-aardvark.c ++++ b/drivers/pci/controller/pci-aardvark.c +@@ -210,6 +210,8 @@ enum { + }; + + #define VENDOR_ID_REG (LMI_BASE_ADDR + 0x44) ++#define DEBUG_MUX_CTRL_REG (LMI_BASE_ADDR + 0x208) ++#define DIS_ORD_CHK BIT(30) + + /* PCIe core controller registers */ + #define CTRL_CORE_BASE_ADDR 0x18000 +@@ -558,6 +560,11 @@ static void advk_pcie_setup_hw(struct ad + PCIE_CORE_CTRL2_TD_ENABLE; + advk_writel(pcie, reg, PCIE_CORE_CTRL2_REG); + ++ /* Disable ordering checks, workaround for erratum 3.12 "PCIe completion timeout" */ ++ reg = advk_readl(pcie, DEBUG_MUX_CTRL_REG); ++ reg |= DIS_ORD_CHK; ++ advk_writel(pcie, reg, DEBUG_MUX_CTRL_REG); ++ + /* Set lane X1 */ + reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); + reg &= ~LANE_CNT_MSK; +@@ -1580,6 +1587,9 @@ static irqreturn_t advk_pcie_irq_handler + struct advk_pcie *pcie = arg; + u32 status; + ++ /* Full memory barrier (ARM dsb sy), workaround for erratum 3.12 "PCIe completion timeout" */ ++ mb(); ++ + status = advk_readl(pcie, HOST_CTRL_INT_STATUS_REG); + if (!(status & PCIE_IRQ_CORE_INT)) + return IRQ_NONE; |