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path: root/drivers/pci/controller/pci-aardvark.c
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Diffstat (limited to 'drivers/pci/controller/pci-aardvark.c')
-rw-r--r--drivers/pci/controller/pci-aardvark.c49
1 files changed, 40 insertions, 9 deletions
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 051b48bd7985..e3f5e7ab7606 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -514,7 +514,7 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie)
udelay(PIO_RETRY_DELAY);
}
- dev_err(dev, "config read/write timed out\n");
+ dev_err(dev, "PIO read/write transfer time out\n");
return -ETIMEDOUT;
}
@@ -657,6 +657,35 @@ static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
return true;
}
+static bool advk_pcie_pio_is_running(struct advk_pcie *pcie)
+{
+ struct device *dev = &pcie->pdev->dev;
+
+ /*
+ * Trying to start a new PIO transfer when previous has not completed
+ * cause External Abort on CPU which results in kernel panic:
+ *
+ * SError Interrupt on CPU0, code 0xbf000002 -- SError
+ * Kernel panic - not syncing: Asynchronous SError Interrupt
+ *
+ * Functions advk_pcie_rd_conf() and advk_pcie_wr_conf() are protected
+ * by raw_spin_lock_irqsave() at pci_lock_config() level to prevent
+ * concurrent calls at the same time. But because PIO transfer may take
+ * about 1.5s when link is down or card is disconnected, it means that
+ * advk_pcie_wait_pio() does not always have to wait for completion.
+ *
+ * Some versions of ARM Trusted Firmware handles this External Abort at
+ * EL3 level and mask it to prevent kernel panic. Relevant TF-A commit:
+ * https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?id=3c7dcdac5c50
+ */
+ if (advk_readl(pcie, PIO_START)) {
+ dev_err(dev, "Previous PIO read/write transfer is still running\n");
+ return true;
+ }
+
+ return false;
+}
+
static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
int where, int size, u32 *val)
{
@@ -673,9 +702,10 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
return pci_bridge_emul_conf_read(&pcie->bridge, where,
size, val);
- /* Start PIO */
- advk_writel(pcie, 0, PIO_START);
- advk_writel(pcie, 1, PIO_ISR);
+ if (advk_pcie_pio_is_running(pcie)) {
+ *val = 0xffffffff;
+ return PCIBIOS_SET_FAILED;
+ }
/* Program the control register */
reg = advk_readl(pcie, PIO_CTRL);
@@ -694,7 +724,8 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
/* Program the data strobe */
advk_writel(pcie, 0xf, PIO_WR_DATA_STRB);
- /* Start the transfer */
+ /* Clear PIO DONE ISR and start the transfer */
+ advk_writel(pcie, 1, PIO_ISR);
advk_writel(pcie, 1, PIO_START);
ret = advk_pcie_wait_pio(pcie);
@@ -734,9 +765,8 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
if (where % size)
return PCIBIOS_SET_FAILED;
- /* Start PIO */
- advk_writel(pcie, 0, PIO_START);
- advk_writel(pcie, 1, PIO_ISR);
+ if (advk_pcie_pio_is_running(pcie))
+ return PCIBIOS_SET_FAILED;
/* Program the control register */
reg = advk_readl(pcie, PIO_CTRL);
@@ -763,7 +793,8 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
/* Program the data strobe */
advk_writel(pcie, data_strobe, PIO_WR_DATA_STRB);
- /* Start the transfer */
+ /* Clear PIO DONE ISR and start the transfer */
+ advk_writel(pcie, 1, PIO_ISR);
advk_writel(pcie, 1, PIO_START);
ret = advk_pcie_wait_pio(pcie);