[PATCH v2 3/3] PCI: j721e: Add PCI legacy interrupt support for J7200

Kishon Vijay Abraham I
2021-08-04T13:29:44Z

Add PCI legacy interrupt support for J7200. J7200 has a single HW
interrupt line for all the four legacy interrupts INTA/INTB/INTC/INTD.
The HW interrupt line connected to GIC is a pulse interrupt whereas
the legacy interrupts by definition is level interrupt. In order to
provide level interrupt functionality to edge interrupt line, PCIe
in J7200 has provided USER_EOI_REG register. When the SW writes to
USER_EOI_REG register after handling the interrupt, the IP checks the
state of legacy interrupt and re-triggers pulse interrupt invoking
the handler again. (Note that the errata in J721E where EOI is not
implemented is fixed in J7200).

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
drivers/pci/controller/cadence/pci-j721e.c | 77 ++++++++++++++++++++--
1 file changed, 71 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c
index c2e7a78dc31f..be8464232be0 100644
--- a/drivers/pci/controller/cadence/pci-j721e.c
+++ b/drivers/pci/controller/cadence/pci-j721e.c
@@ -36,12 +36,24 @@
#define STATUS_CLR_REG_SYS_0 0x700
#define INTx_EN(num) (1 << (num))

+#define ENABLE_REG_SYS_1 0x104
+#define STATUS_REG_SYS_1 0x504
+#define SYS1_INTx_EN(num) (1 << (22 + (num)))
+
#define J721E_PCIE_USER_CMD_STATUS 0x4
#define LINK_TRAINING_ENABLE BIT(0)

#define J721E_PCIE_USER_LINKSTATUS 0x14
#define LINK_STATUS GENMASK(1, 0)

+#define USER_EOI_REG 0xC8
+enum eoi_reg {
+ EOI_DOWNSTREAM_INTERRUPT,
+ EOI_FLR_INTERRUPT,
+ EOI_LEGACY_INTERRUPT,
+ EOI_POWER_STATE_INTERRUPT,
+};
+
enum link_status {
NO_RECEIVERS_DETECTED,
LINK_TRAINING_IN_PROGRESS,
@@ -67,6 +79,7 @@ struct j721e_pcie {
void __iomem *intd_cfg_base;
u32 linkdown_irq_regfield;
struct irq_domain *legacy_irq_domain;
+ unsigned int is_intc_v1:1;
};

enum j721e_pcie_mode {
@@ -76,6 +89,7 @@ enum j721e_pcie_mode {

struct j721e_pcie_data {
enum j721e_pcie_mode mode;
+ unsigned int is_intc_v1:1;
unsigned int quirk_retrain_flag:1;
unsigned int quirk_detect_quiet_flag:1;
u32 linkdown_irq_regfield;
@@ -129,6 +143,39 @@ static void j721e_pcie_config_link_irq(struct j721e_pcie *pcie)
j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_2, reg);
}

+static void j721e_pcie_legacy_irq_handler(struct irq_desc *desc)
+{
+ struct j721e_pcie *pcie = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ int i, virq;
+ u32 reg;
+
+ chained_irq_enter(chip, desc);
+
+ for (i = 0; i < PCI_NUM_INTX; i++) {
+ reg = j721e_pcie_intd_readl(pcie, STATUS_REG_SYS_1);
+ if (!(reg & SYS1_INTx_EN(i)))
+ continue;
+
+ virq = irq_find_mapping(pcie->legacy_irq_domain, i);
+ generic_handle_irq(virq);
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static void j721e_pcie_irq_eoi(struct irq_data *data)
+{
+ struct j721e_pcie *pcie = irq_data_get_irq_chip_data(data);
+
+ j721e_pcie_user_writel(pcie, USER_EOI_REG, EOI_LEGACY_INTERRUPT);
+}
+
+struct irq_chip j721e_pcie_irq_chip = {
+ .name = "J721E-PCIE-INTX",
+ .irq_eoi = j721e_pcie_irq_eoi,
+};
+
static void j721e_pcie_v1_legacy_irq_handler(struct irq_desc *desc)
{
struct j721e_pcie *pcie = irq_desc_get_handler_data(desc);
@@ -153,8 +200,14 @@ static void j721e_pcie_v1_legacy_irq_handler(struct irq_desc *desc)

static int j721e_pcie_intx_map(struct irq_domain *domain, unsigned int irq, irq_hw_number_t hwirq)
{
- irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
- irq_set_chip_data(irq, domain->host_data);
+ struct j721e_pcie *pcie = domain->host_data;
+
+ if (pcie->is_intc_v1)
+ irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_simple_irq);
+ else
+ irq_set_chip_and_handler(irq, &j721e_pcie_irq_chip, handle_fasteoi_irq);
+
+ irq_set_chip_data(irq, pcie);

return 0;
}
@@ -183,7 +236,11 @@ static int j721e_pcie_config_legacy_irq(struct j721e_pcie *pcie)
dev_err(dev, "Failed to parse and map legacy irq\n");
return -EINVAL;
}
- irq_set_chained_handler_and_data(irq, j721e_pcie_v1_legacy_irq_handler, pcie);
+
+ if (pcie->is_intc_v1)
+ irq_set_chained_handler_and_data(irq, j721e_pcie_v1_legacy_irq_handler, pcie);
+ else
+ irq_set_chained_handler_and_data(irq, j721e_pcie_legacy_irq_handler, pcie);

legacy_irq_domain = irq_domain_add_linear(intc_node, PCI_NUM_INTX,
&j721e_pcie_intx_domain_ops, pcie);
@@ -194,9 +251,15 @@ static int j721e_pcie_config_legacy_irq(struct j721e_pcie *pcie)
pcie->legacy_irq_domain = legacy_irq_domain;

for (i = 0; i < PCI_NUM_INTX; i++) {
- reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_0);
- reg |= INTx_EN(i);
- j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_0, reg);
+ if (pcie->is_intc_v1) {
+ reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_0);
+ reg |= INTx_EN(i);
+ j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_0, reg);
+ } else {
+ reg = j721e_pcie_intd_readl(pcie, ENABLE_REG_SYS_1);
+ reg |= SYS1_INTx_EN(i);
+ j721e_pcie_intd_writel(pcie, ENABLE_REG_SYS_1, reg);
+ }
}

return 0;
@@ -372,6 +435,7 @@ static const struct j721e_pcie_data j721e_pcie_rc_data = {
.quirk_retrain_flag = true,
.byte_access_allowed = false,
.linkdown_irq_regfield = LINK_DOWN,
+ .is_intc_v1 = true,
};

static const struct j721e_pcie_data j721e_pcie_ep_data = {
@@ -514,6 +578,7 @@ static int j721e_pcie_probe(struct platform_device *pdev)
goto err_get_sync;
}

+ pcie->is_intc_v1 = data->is_intc_v1;
ret = j721e_pcie_config_legacy_irq(pcie);
if (ret < 0)
goto err_get_sync;
--
2.17.1