Re: [PATCH v2 2/4] PCI: dwc: rockchip: add legacy interrupt support
From: Marc Zyngier
Date: Thu Apr 14 2022 - 16:36:49 EST
On 2022-04-13 14:37, Peter Geis wrote:
The legacy interrupts on the rk356x pcie controller are handled by a
single muxed interrupt. Add irq domain support to the pcie-dw-rockchip
driver to support the virtual domain.
Signed-off-by: Peter Geis <pgwipeout@xxxxxxxxx>
---
drivers/pci/controller/dwc/pcie-dw-rockchip.c | 123 +++++++++++++++++-
1 file changed, 121 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index c9b341e55cbb..a8b1dc03d3cc 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -10,9 +10,12 @@
#include <linux/clk.h>
#include <linux/gpio/consumer.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/of_irq.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
@@ -36,10 +39,13 @@
#define PCIE_LINKUP (PCIE_SMLH_LINKUP | PCIE_RDLH_LINKUP)
#define PCIE_L0S_ENTRY 0x11
#define PCIE_CLIENT_GENERAL_CONTROL 0x0
+#define PCIE_CLIENT_INTR_STATUS_LEGACY 0x8
+#define PCIE_CLIENT_INTR_MASK_LEGACY 0x1c
#define PCIE_CLIENT_GENERAL_DEBUG 0x104
-#define PCIE_CLIENT_HOT_RESET_CTRL 0x180
+#define PCIE_CLIENT_HOT_RESET_CTRL 0x180
#define PCIE_CLIENT_LTSSM_STATUS 0x300
-#define PCIE_LTSSM_ENABLE_ENHANCE BIT(4)
+#define PCIE_LEGACY_INT_ENABLE GENMASK(3, 0)
+#define PCIE_LTSSM_ENABLE_ENHANCE BIT(4)
#define PCIE_LTSSM_STATUS_MASK GENMASK(5, 0)
struct rockchip_pcie {
@@ -51,6 +57,8 @@ struct rockchip_pcie {
struct reset_control *rst;
struct gpio_desc *rst_gpio;
struct regulator *vpcie3v3;
+ struct irq_domain *irq_domain;
+ raw_spinlock_t irq_lock;
};
static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
@@ -65,6 +73,105 @@ static void rockchip_pcie_writel_apb(struct
rockchip_pcie *rockchip,
writel_relaxed(val, rockchip->apb_base + reg);
}
+static void rockchip_pcie_legacy_int_handler(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct rockchip_pcie *rockchip = irq_desc_get_handler_data(desc);
+ struct device *dev = rockchip->pci.dev;
+ u32 reg;
+ u32 hwirq;
+ u32 virq;
+
+ chained_irq_enter(chip, desc);
+
+ reg = rockchip_pcie_readl_apb(rockchip,
PCIE_CLIENT_INTR_STATUS_LEGACY);
+
+ while (reg) {
+ hwirq = ffs(reg) - 1;
+ reg &= ~BIT(hwirq);
The whole construct would be better served by for_each_set_bit().
+
+ virq = irq_find_mapping(rockchip->irq_domain, hwirq);
+ if (virq)
+ generic_handle_irq(virq);
Please replace this with generic_handle_domain_irq().
+ else
+ dev_err(dev, "unexpected IRQ, INT%d\n", hwirq);
This hardly serves any purpose. At best, this is a debug statement.
At worse, this is a DoS. In any case, please remove it.
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static void rockchip_intx_mask(struct irq_data *data)
+{
+ struct rockchip_pcie *rockchip = irq_data_get_irq_chip_data(data);
+ unsigned long flags;
+ u32 val;
+
+ /* disable legacy interrupts */
+ raw_spin_lock_irqsave(&rockchip->irq_lock, flags);
+ val = HIWORD_UPDATE_BIT(PCIE_LEGACY_INT_ENABLE);
+ val |= PCIE_LEGACY_INT_ENABLE;
+ rockchip_pcie_writel_apb(rockchip, val,
PCIE_CLIENT_INTR_MASK_LEGACY);
+ raw_spin_unlock_irqrestore(&rockchip->irq_lock, flags);
+};
+
+static void rockchip_intx_unmask(struct irq_data *data)
+{
+ struct rockchip_pcie *rockchip = irq_data_get_irq_chip_data(data);
+ unsigned long flags;
+ u32 val;
+
+ /* enable legacy interrupts */
+ raw_spin_lock_irqsave(&rockchip->irq_lock, flags);
+ val = HIWORD_UPDATE_BIT(PCIE_LEGACY_INT_ENABLE);
+ val &= ~PCIE_LEGACY_INT_ENABLE;
+ rockchip_pcie_writel_apb(rockchip, val,
PCIE_CLIENT_INTR_MASK_LEGACY);
+ raw_spin_unlock_irqrestore(&rockchip->irq_lock, flags);
+};
+
+static struct irq_chip rockchip_intx_irq_chip = {
+ .flags = IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MASK_ON_SUSPEND,
+ .irq_mask = rockchip_intx_mask,
+ .irq_unmask = rockchip_intx_unmask,
+ .name = "INTx",
For consistency, please place 'name' at the top, and 'flags' at the end.
+};
+
+static int rockchip_pcie_intx_map(struct irq_domain *domain, unsigned
int irq,
+ irq_hw_number_t hwirq)
+{
+ irq_set_chip_and_handler(irq, &rockchip_intx_irq_chip,
handle_simple_irq);
Why isn't this a *level* handler, as per the PCI spec?
+ irq_set_chip_data(irq, domain->host_data);
+
+ return 0;
+}
+
+static const struct irq_domain_ops intx_domain_ops = {
+ .map = rockchip_pcie_intx_map,
+};
+
+static int rockchip_pcie_init_irq_domain(struct rockchip_pcie
*rockchip)
+{
+ struct device *dev = rockchip->pci.dev;
+ struct device_node *intc;
+
+ raw_spin_lock_init(&rockchip->irq_lock);
+
+ intc = of_get_child_by_name(dev->of_node,
"legacy-interrupt-controller");
+ if (!intc) {
+ dev_err(dev, "missing child interrupt-controller node\n");
+ return -EINVAL;
+ }
+
+ rockchip->irq_domain = irq_domain_add_linear(intc, PCI_NUM_INTX,
+ &intx_domain_ops, rockchip);
+ of_node_put(intc);
+ if (!rockchip->irq_domain) {
+ dev_err(dev, "failed to get a INTx IRQ domain\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static void rockchip_pcie_enable_ltssm(struct rockchip_pcie *rockchip)
{
rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_ENABLE_LTSSM,
@@ -111,7 +218,19 @@ static int rockchip_pcie_host_init(struct
pcie_port *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+ struct device *dev = rockchip->pci.dev;
u32 val = HIWORD_UPDATE_BIT(PCIE_LTSSM_ENABLE_ENHANCE);
+ int irq, ret;
+
+ irq = of_irq_get_byname(dev->of_node, "legacy");
+ if (irq < 0)
+ return irq;
+
+ irq_set_chained_handler_and_data(irq,
rockchip_pcie_legacy_int_handler, rockchip);
+
Installing the handler before the domain is instantiated is
unlikely to end well if you have a pending interrupt...
+ ret = rockchip_pcie_init_irq_domain(rockchip);
+ if (ret < 0)
+ dev_err(dev, "failed to init irq domain\n");
/* LTSSM enable control mode */
rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_HOT_RESET_CTRL);
Thanks,
M.
--
Jazz is not dead. It just smells funny...