Due an issue with PCIe wrapper around DWC PCIe IP on dra7xx, driver
needs to ensure that there are no pending MSI IRQ vector set (i.e
PCIE_MSI_INTR0_STATUS reads 0 at least once) before exiting IRQ handler.
Else, the dra7xx PCIe wrapper will not register new MSI IRQs even though
PCIE_MSI_INTR0_STATUS shows IRQs are pending.
Therefore its no longer possible to use default IRQ handler provided by
DWC library. So, add irqchip implementation inside pci-dra7xx.c and
install new MSI IRQ handler to handle above errata.
This fixes a bug, where PCIe wifi cards with 4 DMA queues like Intel
8260 used to throw following error and stall during ping/iperf3 tests.
[ 97.776310] iwlwifi 0000:01:00.0: Queue 9 stuck for 2500 ms.
Signed-off-by: Vignesh Raghavendra <vigneshr@xxxxxx>
Acked-by: Kishon Vijay Abraham I <kishon@xxxxxx>
Tested-by: Kishon Vijay Abraham I <kishon@xxxxxx>
---
v4:
Simplify dra7xx_pcie_handle_msi_irq() by spliting inner loop into
separte function as suggested by Lorenzo
v3:
- Move loop to service all MSI IRQs into dra7xx_pcie_handle_msi_irq()
- Add a warning msg when loop counter overflows
drivers/pci/controller/dwc/pci-dra7xx.c | 231 ++++++++++++++++++++----
1 file changed, 195 insertions(+), 36 deletions(-)
diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
index 9bf7fa99b103..3b0e58f2de58 100644
--- a/drivers/pci/controller/dwc/pci-dra7xx.c
+++ b/drivers/pci/controller/dwc/pci-dra7xx.c
@@ -215,10 +215,6 @@ static int dra7xx_pcie_host_init(struct pcie_port *pp)
return 0;
}
-static const struct dw_pcie_host_ops dra7xx_pcie_host_ops = {
- .host_init = dra7xx_pcie_host_init,
-};
-
static int dra7xx_pcie_intx_map(struct irq_domain *domain, unsigned int irq,
irq_hw_number_t hwirq)
{
@@ -233,43 +229,77 @@ static const struct irq_domain_ops intx_domain_ops = {
.xlate = pci_irqd_intx_xlate,
};
-static int dra7xx_pcie_init_irq_domain(struct pcie_port *pp)
+static int dra7xx_pcie_handle_msi(struct pcie_port *pp, int index)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
- struct device *dev = pci->dev;
- struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci);
- struct device_node *node = dev->of_node;
- struct device_node *pcie_intc_node = of_get_next_child(node, NULL);
+ unsigned long val;
+ int pos, irq;
- if (!pcie_intc_node) {
- dev_err(dev, "No PCIe Intc node found\n");
- return -ENODEV;
- }
+ val = dw_pcie_readl_dbi(pci, PCIE_MSI_INTR0_STATUS +
+ (index * MSI_REG_CTRL_BLOCK_SIZE));
+ if (!val)
+ return 0;
- dra7xx->irq_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX,
- &intx_domain_ops, pp);
- of_node_put(pcie_intc_node);
- if (!dra7xx->irq_domain) {
- dev_err(dev, "Failed to get a INTx IRQ domain\n");
- return -ENODEV;
+ pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL, 0);
+ while (pos != MAX_MSI_IRQS_PER_CTRL) {
+ irq = irq_find_mapping(pp->irq_domain,
+ (index * MAX_MSI_IRQS_PER_CTRL) + pos);
+ generic_handle_irq(irq);
+ pos++;
+ pos = find_next_bit(&val, MAX_MSI_IRQS_PER_CTRL, pos);
}
- return 0;
+ return 1;
}
-static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, void *arg)
+static void dra7xx_pcie_handle_msi_irq(struct pcie_port *pp)
{
- struct dra7xx_pcie *dra7xx = arg;
- struct dw_pcie *pci = dra7xx->pci;
- struct pcie_port *pp = &pci->pp;
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ int ret, i, count, num_ctrls;
+
+ num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+
+ /**
+ * Need to make sure all MSI status bits read 0 before exiting.
+ * Else, new MSI IRQs are not registered by the wrapper. Have an
+ * upperbound for the loop and exit the IRQ in case of IRQ flood
+ * to avoid locking up system in interrupt context.
+ */
+ count = 0;
+ do {
+ ret = 0;
+
+ for (i = 0; i < num_ctrls; i++)
+ ret |= dra7xx_pcie_handle_msi(pp, i);
+ count++;
+ } while (ret && count <= 1000);
+
+ if (count > 1000)
+ dev_warn_ratelimited(pci->dev,
+ "Too many MSI IRQs to handle\n");
+}
+
+static void dra7xx_pcie_msi_irq_handler(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct dra7xx_pcie *dra7xx;
+ struct dw_pcie *pci;
+ struct pcie_port *pp;
unsigned long reg;
u32 virq, bit;
+ chained_irq_enter(chip, desc);
+
+ pp = irq_desc_get_handler_data(desc);
+ pci = to_dw_pcie_from_pp(pp);
+ dra7xx = to_dra7xx_pcie(pci);
+
reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI);
+ dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg);
switch (reg) {
case MSI:
- dw_handle_msi_irq(pp);
+ dra7xx_pcie_handle_msi_irq(pp);
break;
case INTA:
case INTB:
@@ -283,9 +313,7 @@ static irqreturn_t dra7xx_pcie_msi_irq_handler(int irq, void *arg)
break;
}
- dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_IRQSTATUS_MSI, reg);
-
- return IRQ_HANDLED;
+ chained_irq_exit(chip, desc);
}
static irqreturn_t dra7xx_pcie_irq_handler(int irq, void *arg)
@@ -347,6 +375,145 @@ static irqreturn_t dra7xx_pcie_irq_handler(int irq, void *arg)
return IRQ_HANDLED;
}
+static int dra7xx_pcie_init_irq_domain(struct pcie_port *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ struct device *dev = pci->dev;
+ struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci);
+ struct device_node *node = dev->of_node;
+ struct device_node *pcie_intc_node = of_get_next_child(node, NULL);
+
+ if (!pcie_intc_node) {
+ dev_err(dev, "No PCIe Intc node found\n");
+ return -ENODEV;
+ }
+
+ irq_set_chained_handler_and_data(pp->irq, dra7xx_pcie_msi_irq_handler,
+ pp);
+ dra7xx->irq_domain = irq_domain_add_linear(pcie_intc_node, PCI_NUM_INTX,
+ &intx_domain_ops, pp);
+ of_node_put(pcie_intc_node);
+ if (!dra7xx->irq_domain) {
+ dev_err(dev, "Failed to get a INTx IRQ domain\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void dra7xx_pcie_setup_msi_msg(struct irq_data *d, struct msi_msg *msg)
+{
+ struct pcie_port *pp = irq_data_get_irq_chip_data(d);
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ u64 msi_target;
+
+ msi_target = (u64)pp->msi_data;
+
+ msg->address_lo = lower_32_bits(msi_target);
+ msg->address_hi = upper_32_bits(msi_target);
+
+ msg->data = d->hwirq;
+
+ dev_dbg(pci->dev, "msi#%d address_hi %#x address_lo %#x\n",
+ (int)d->hwirq, msg->address_hi, msg->address_lo);
+}
+
+static int dra7xx_pcie_msi_set_affinity(struct irq_data *d,
+ const struct cpumask *mask,
+ bool force)
+{
+ return -EINVAL;
+}
+
+static void dra7xx_pcie_bottom_mask(struct irq_data *d)
+{
+ struct pcie_port *pp = irq_data_get_irq_chip_data(d);
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ unsigned int res, bit, ctrl;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pp->lock, flags);
+
+ ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL;
+ res = ctrl * MSI_REG_CTRL_BLOCK_SIZE;
+ bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL;
+
+ pp->irq_mask[ctrl] |= BIT(bit);
+ dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK + res,
+ pp->irq_mask[ctrl]);
+
+ raw_spin_unlock_irqrestore(&pp->lock, flags);
+}
+
+static void dra7xx_pcie_bottom_unmask(struct irq_data *d)
+{
+ struct pcie_port *pp = irq_data_get_irq_chip_data(d);
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ unsigned int res, bit, ctrl;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&pp->lock, flags);
+
+ ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL;
+ res = ctrl * MSI_REG_CTRL_BLOCK_SIZE;
+ bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL;
+
+ pp->irq_mask[ctrl] &= ~BIT(bit);
+ dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK + res,
+ pp->irq_mask[ctrl]);
+
+ raw_spin_unlock_irqrestore(&pp->lock, flags);
+}
+
+static void dra7xx_pcie_bottom_ack(struct irq_data *d)
+{
+ struct pcie_port *pp = irq_data_get_irq_chip_data(d);
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ unsigned int res, bit, ctrl;
+
+ ctrl = d->hwirq / MAX_MSI_IRQS_PER_CTRL;
+ res = ctrl * MSI_REG_CTRL_BLOCK_SIZE;
+ bit = d->hwirq % MAX_MSI_IRQS_PER_CTRL;
+
+ dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_STATUS + res, BIT(bit));
+}
+
+static struct irq_chip dra7xx_pci_msi_bottom_irq_chip = {
+ .name = "DRA7XX-PCI-MSI",
+ .irq_ack = dra7xx_pcie_bottom_ack,
+ .irq_compose_msi_msg = dra7xx_pcie_setup_msi_msg,
+ .irq_set_affinity = dra7xx_pcie_msi_set_affinity,
+ .irq_mask = dra7xx_pcie_bottom_mask,
+ .irq_unmask = dra7xx_pcie_bottom_unmask,
+};
+
+static int dra7xx_pcie_msi_host_init(struct pcie_port *pp)
+{
+ struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+ u32 ctrl, num_ctrls;
+
+ pp->msi_irq_chip = &dra7xx_pci_msi_bottom_irq_chip;
+
+ num_ctrls = pp->num_vectors / MAX_MSI_IRQS_PER_CTRL;
+ /* Initialize IRQ Status array */
+ for (ctrl = 0; ctrl < num_ctrls; ctrl++) {
+ pp->irq_mask[ctrl] = ~0;
+ dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_MASK +
+ (ctrl * MSI_REG_CTRL_BLOCK_SIZE),
+ pp->irq_mask[ctrl]);
+ dw_pcie_writel_dbi(pci, PCIE_MSI_INTR0_ENABLE +
+ (ctrl * MSI_REG_CTRL_BLOCK_SIZE),
+ ~0);
+ }
+
+ return dw_pcie_allocate_domains(pp);
+}
+
+static const struct dw_pcie_host_ops dra7xx_pcie_host_ops = {
+ .host_init = dra7xx_pcie_host_init,
+ .msi_host_init = dra7xx_pcie_msi_host_init,
+};
+
static void dra7xx_pcie_ep_init(struct dw_pcie_ep *ep)
{
struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
@@ -467,14 +634,6 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
return pp->irq;
}
- ret = devm_request_irq(dev, pp->irq, dra7xx_pcie_msi_irq_handler,
- IRQF_SHARED | IRQF_NO_THREAD,
- "dra7-pcie-msi", dra7xx);
- if (ret) {
- dev_err(dev, "failed to request irq\n");
- return ret;
- }
-
ret = dra7xx_pcie_init_irq_domain(pp);
if (ret < 0)
return ret;
--
2.26.0
