[PATCH V8 3/3] irqchip: qcom: Add IRQ combiner driver

Agustin Vega-Frias
2016-11-29T22:58:03Z

Driver for interrupt combiners in the Top-level Control and Status
Registers (TCSR) hardware block in Qualcomm Technologies chips.

An interrupt combiner in this block combines a set of interrupts by
OR'ing the individual interrupt signals into a summary interrupt
signal routed to a parent interrupt controller, and provides read-
only, 32-bit registers to query the status of individual interrupts.
The status bit for IRQ n is bit (n % 32) within register (n / 32)
of the given combiner. Thus, each combiner can be described as a set
of register offsets and the number of IRQs managed.

Signed-off-by: Agustin Vega-Frias <agustinv@codeaurora.org>
---
drivers/irqchip/Kconfig | 8 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/qcom-irq-combiner.c | 337 ++++++++++++++++++++++++++++++++++++
3 files changed, 346 insertions(+)
create mode 100644 drivers/irqchip/qcom-irq-combiner.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index bc0af33..610f902 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -279,3 +279,11 @@ config EZNPS_GIC
config STM32_EXTI
bool
select IRQ_DOMAIN
+
+config QCOM_IRQ_COMBINER
+ bool "QCOM IRQ combiner support"
+ depends on ARCH_QCOM
+ select IRQ_DOMAIN
+ help
+ Say yes here to add support for the IRQ combiner devices embedded
+ in Qualcomm Technologies chips.
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e4dbfc8..1818a0b 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -74,3 +74,4 @@ obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o
obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o
obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o
obj-$(CONFIG_STM32_EXTI) += irq-stm32-exti.o
+obj-$(CONFIG_QCOM_IRQ_COMBINER) += qcom-irq-combiner.o
diff --git a/drivers/irqchip/qcom-irq-combiner.c b/drivers/irqchip/qcom-irq-combiner.c
new file mode 100644
index 0000000..fc25251
--- /dev/null
+++ b/drivers/irqchip/qcom-irq-combiner.c
@@ -0,0 +1,337 @@
+/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * Driver for interrupt combiners in the Top-level Control and Status
+ * Registers (TCSR) hardware block in Qualcomm Technologies chips.
+ * An interrupt combiner in this block combines a set of interrupts by
+ * OR'ing the individual interrupt signals into a summary interrupt
+ * signal routed to a parent interrupt controller, and provides read-
+ * only, 32-bit registers to query the status of individual interrupts.
+ * The status bit for IRQ n is bit (n % 32) within register (n / 32)
+ * of the given combiner. Thus, each combiner can be described as a set
+ * of register offsets and the number of IRQs managed.
+ */
+
+#include <linux/acpi.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/platform_device.h>
+
+#define REG_SIZE 32
+
+struct combiner_reg {
+ void __iomem *addr;
+ unsigned long mask;
+};
+
+struct combiner {
+ struct irq_chip irq_chip;
+ struct irq_domain *domain;
+ int parent_irq;
+ u32 nirqs;
+ u32 nregs;
+ struct combiner_reg regs[0];
+};
+
+static inline u32 irq_register(int irq)
+{
+ return irq / REG_SIZE;
+}
+
+static inline u32 irq_bit(int irq)
+{
+ return irq % REG_SIZE;
+
+}
+
+static inline int irq_nr(u32 reg, u32 bit)
+{
+ return reg * REG_SIZE + bit;
+}
+
+/*
+ * Handler for the cascaded IRQ.
+ */
+static void combiner_handle_irq(struct irq_desc *desc)
+{
+ struct combiner *combiner = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ u32 reg;
+
+ chained_irq_enter(chip, desc);
+
+ for (reg = 0; reg < combiner->nregs; reg++) {
+ int virq;
+ int hwirq;
+ u32 bit;
+ u32 status;
+
+ if (combiner->regs[reg].mask == 0)
+ continue;
+
+ status = readl_relaxed(combiner->regs[reg].addr);
+ status &= combiner->regs[reg].mask;
+
+ while (status) {
+ bit = __ffs(status);
+ status &= ~(1 << bit);
+ hwirq = irq_nr(reg, bit);
+ virq = irq_find_mapping(combiner->domain, hwirq);
+ if (virq >= 0)
+ generic_handle_irq(virq);
+
+ }
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+/*
+ * irqchip callbacks
+ */
+
+static void combiner_irq_chip_mask_irq(struct irq_data *data)
+{
+ struct combiner *combiner = irq_data_get_irq_chip_data(data);
+ struct combiner_reg *reg = combiner->regs + irq_register(data->hwirq);
+
+ clear_bit(irq_bit(data->hwirq), &reg->mask);
+}
+
+static void combiner_irq_chip_unmask_irq(struct irq_data *data)
+{
+ struct combiner *combiner = irq_data_get_irq_chip_data(data);
+ struct combiner_reg *reg = combiner->regs + irq_register(data->hwirq);
+
+ set_bit(irq_bit(data->hwirq), &reg->mask);
+}
+
+/*
+ * irq_domain_ops callbacks
+ */
+
+static int combiner_irq_map(struct irq_domain *domain, unsigned int irq,
+ irq_hw_number_t hwirq)
+{
+ struct combiner *combiner = domain->host_data;
+
+ if (hwirq >= combiner->nirqs)
+ return -EINVAL;
+
+ irq_set_chip_and_handler(irq, &combiner->irq_chip, handle_level_irq);
+ irq_set_chip_data(irq, combiner);
+ irq_set_parent(irq, combiner->parent_irq);
+ irq_set_noprobe(irq);
+ return 0;
+}
+
+static void combiner_irq_unmap(struct irq_domain *domain, unsigned int irq)
+{
+ irq_set_chip_and_handler(irq, NULL, NULL);
+ irq_set_chip_data(irq, NULL);
+ irq_set_parent(irq, -1);
+}
+
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+static int combiner_irq_translate(struct irq_domain *d, struct irq_fwspec *fws,
+ unsigned long *hwirq, unsigned int *type)
+{
+ if (is_acpi_node(fws->fwnode)) {
+ if (fws->param_count != 2)
+ return -EINVAL;
+
+ *hwirq = fws->param[0];
+ *type = fws->param[1];
+ return 0;
+ }
+
+ return -EINVAL;
+}
+#endif
+
+static const struct irq_domain_ops domain_ops = {
+ .map = combiner_irq_map,
+ .unmap = combiner_irq_unmap,
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+ .translate = combiner_irq_translate
+#endif
+};
+
+/*
+ * Device probing
+ */
+
+#ifdef CONFIG_ACPI
+
+static acpi_status count_registers_cb(struct acpi_resource *ares, void *context)
+{
+ int *count = context;
+
+ if (ares->type == ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
+ ++(*count);
+ return AE_OK;
+}
+
+static int count_registers(struct platform_device *pdev)
+{
+ struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+ acpi_status status;
+ int count = 0;
+
+ if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
+ return -EINVAL;
+
+ status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
+ count_registers_cb, &count);
+ if (ACPI_FAILURE(status))
+ return -EINVAL;
+ return count;
+}
+
+struct get_registers_context {
+ struct device *dev;
+ struct combiner *combiner;
+ int err;
+};
+
+static acpi_status get_registers_cb(struct acpi_resource *ares, void *context)
+{
+ struct get_registers_context *ctx = context;
+ struct acpi_resource_generic_register *reg;
+ phys_addr_t paddr;
+ void __iomem *vaddr;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_GENERIC_REGISTER)
+ return AE_OK;
+
+ reg = &ares->data.generic_reg;
+ paddr = reg->address;
+ if ((reg->space_id != ACPI_SPACE_MEM) ||
+ (reg->bit_offset != 0) ||
+ (reg->bit_width > REG_SIZE)) {
+ dev_err(ctx->dev, "Bad register resource @%pa\n", &paddr);
+ ctx->err = -EINVAL;
+ return AE_ERROR;
+ }
+
+ vaddr = devm_ioremap(ctx->dev, reg->address, REG_SIZE);
+ if (IS_ERR(vaddr)) {
+ dev_err(ctx->dev, "Can't map register @%pa\n", &paddr);
+ ctx->err = PTR_ERR(vaddr);
+ return AE_ERROR;
+ }
+
+ ctx->combiner->regs[ctx->combiner->nregs].addr = vaddr;
+ ctx->combiner->nirqs += reg->bit_width;
+ ctx->combiner->nregs++;
+ return AE_OK;
+}
+
+static int get_registers(struct platform_device *pdev, struct combiner *comb)
+{
+ struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+ acpi_status status;
+ struct get_registers_context ctx;
+
+ if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
+ return -EINVAL;
+
+ ctx.dev = &pdev->dev;
+ ctx.combiner = comb;
+ ctx.err = 0;
+
+ status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
+ get_registers_cb, &ctx);
+ if (ACPI_FAILURE(status))
+ return ctx.err;
+ return 0;
+}
+
+#else /* !CONFIG_ACPI */
+
+static int count_registers(struct platform_device *pdev)
+{
+ return -EINVAL;
+}
+
+static int get_registers(struct platform_device *pdev, struct combiner *comb)
+{
+ return -EINVAL;
+}
+
+#endif
+
+static int __init combiner_probe(struct platform_device *pdev)
+{
+ struct combiner *combiner;
+ size_t alloc_sz;
+ u32 nregs;
+ int err;
+
+ nregs = count_registers(pdev);
+ if (nregs <= 0) {
+ dev_err(&pdev->dev, "Error reading register resources\n");
+ return -EINVAL;
+ }
+
+ alloc_sz = sizeof(*combiner) + sizeof(struct combiner_reg) * nregs;
+ combiner = devm_kzalloc(&pdev->dev, alloc_sz, GFP_KERNEL);
+ if (!combiner)
+ return -ENOMEM;
+
+ err = get_registers(pdev, combiner);
+ if (err < 0)
+ return err;
+
+ combiner->parent_irq = platform_get_irq(pdev, 0);
+ if (combiner->parent_irq <= 0) {
+ dev_err(&pdev->dev, "Error getting IRQ resource\n");
+ return -EINVAL;
+ }
+
+ combiner->domain = irq_domain_create_linear(
+ pdev->dev.fwnode, combiner->nirqs, &domain_ops, combiner);
+ if (!combiner->domain)
+ /* Errors printed by irq_domain_create_linear */
+ return -ENODEV;
+
+ irq_set_chained_handler_and_data(combiner->parent_irq,
+ combiner_handle_irq, combiner);
+ combiner->irq_chip.irq_mask = combiner_irq_chip_mask_irq;
+ combiner->irq_chip.irq_unmask = combiner_irq_chip_unmask_irq;
+ combiner->irq_chip.name = pdev->name;
+
+ dev_info(&pdev->dev, "Initialized with [p=%d,n=%d,r=%p]\n",
+ combiner->parent_irq, combiner->nirqs, combiner->regs[0].addr);
+ return 0;
+}
+
+static const struct acpi_device_id qcom_irq_combiner_acpi_match[] = {
+ { "QCOM80B1", },
+ { }
+};
+
+static struct platform_driver qcom_irq_combiner_probe = {
+ .driver = {
+ .name = "qcom-irq-combiner",
+ .owner = THIS_MODULE,
+ .acpi_match_table = ACPI_PTR(qcom_irq_combiner_acpi_match),
+ },
+ .probe = combiner_probe,
+};
+
+static int __init register_qcom_irq_combiner(void)
+{
+ return platform_driver_register(&qcom_irq_combiner_probe);
+}
+device_initcall(register_qcom_irq_combiner);
--
Qualcomm Datacenter Technologies, Inc. on behalf of the Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.