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path: root/drivers/pci/controller/pci-xgene-msi.c
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Diffstat (limited to 'drivers/pci/controller/pci-xgene-msi.c')
-rw-r--r--drivers/pci/controller/pci-xgene-msi.c543
1 files changed, 543 insertions, 0 deletions
diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
new file mode 100644
index 000000000000..f4c02da84e59
--- /dev/null
+++ b/drivers/pci/controller/pci-xgene-msi.c
@@ -0,0 +1,543 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * APM X-Gene MSI Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Tanmay Inamdar <tinamdar@apm.com>
+ * Duc Dang <dhdang@apm.com>
+ */
+#include <linux/cpu.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/of_pci.h>
+
+#define MSI_IR0 0x000000
+#define MSI_INT0 0x800000
+#define IDX_PER_GROUP 8
+#define IRQS_PER_IDX 16
+#define NR_HW_IRQS 16
+#define NR_MSI_VEC (IDX_PER_GROUP * IRQS_PER_IDX * NR_HW_IRQS)
+
+struct xgene_msi_group {
+ struct xgene_msi *msi;
+ int gic_irq;
+ u32 msi_grp;
+};
+
+struct xgene_msi {
+ struct device_node *node;
+ struct irq_domain *inner_domain;
+ struct irq_domain *msi_domain;
+ u64 msi_addr;
+ void __iomem *msi_regs;
+ unsigned long *bitmap;
+ struct mutex bitmap_lock;
+ struct xgene_msi_group *msi_groups;
+ int num_cpus;
+};
+
+/* Global data */
+static struct xgene_msi xgene_msi_ctrl;
+
+static struct irq_chip xgene_msi_top_irq_chip = {
+ .name = "X-Gene1 MSI",
+ .irq_enable = pci_msi_unmask_irq,
+ .irq_disable = pci_msi_mask_irq,
+ .irq_mask = pci_msi_mask_irq,
+ .irq_unmask = pci_msi_unmask_irq,
+};
+
+static struct msi_domain_info xgene_msi_domain_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_PCI_MSIX),
+ .chip = &xgene_msi_top_irq_chip,
+};
+
+/*
+ * X-Gene v1 has 16 groups of MSI termination registers MSInIRx, where
+ * n is group number (0..F), x is index of registers in each group (0..7)
+ * The register layout is as follows:
+ * MSI0IR0 base_addr
+ * MSI0IR1 base_addr + 0x10000
+ * ... ...
+ * MSI0IR6 base_addr + 0x60000
+ * MSI0IR7 base_addr + 0x70000
+ * MSI1IR0 base_addr + 0x80000
+ * MSI1IR1 base_addr + 0x90000
+ * ... ...
+ * MSI1IR7 base_addr + 0xF0000
+ * MSI2IR0 base_addr + 0x100000
+ * ... ...
+ * MSIFIR0 base_addr + 0x780000
+ * MSIFIR1 base_addr + 0x790000
+ * ... ...
+ * MSIFIR7 base_addr + 0x7F0000
+ * MSIINT0 base_addr + 0x800000
+ * MSIINT1 base_addr + 0x810000
+ * ... ...
+ * MSIINTF base_addr + 0x8F0000
+ *
+ * Each index register supports 16 MSI vectors (0..15) to generate interrupt.
+ * There are total 16 GIC IRQs assigned for these 16 groups of MSI termination
+ * registers.
+ *
+ * Each MSI termination group has 1 MSIINTn register (n is 0..15) to indicate
+ * the MSI pending status caused by 1 of its 8 index registers.
+ */
+
+/* MSInIRx read helper */
+static u32 xgene_msi_ir_read(struct xgene_msi *msi,
+ u32 msi_grp, u32 msir_idx)
+{
+ return readl_relaxed(msi->msi_regs + MSI_IR0 +
+ (msi_grp << 19) + (msir_idx << 16));
+}
+
+/* MSIINTn read helper */
+static u32 xgene_msi_int_read(struct xgene_msi *msi, u32 msi_grp)
+{
+ return readl_relaxed(msi->msi_regs + MSI_INT0 + (msi_grp << 16));
+}
+
+/*
+ * With 2048 MSI vectors supported, the MSI message can be constructed using
+ * following scheme:
+ * - Divide into 8 256-vector groups
+ * Group 0: 0-255
+ * Group 1: 256-511
+ * Group 2: 512-767
+ * ...
+ * Group 7: 1792-2047
+ * - Each 256-vector group is divided into 16 16-vector groups
+ * As an example: 16 16-vector groups for 256-vector group 0-255 is
+ * Group 0: 0-15
+ * Group 1: 16-32
+ * ...
+ * Group 15: 240-255
+ * - The termination address of MSI vector in 256-vector group n and 16-vector
+ * group x is the address of MSIxIRn
+ * - The data for MSI vector in 16-vector group x is x
+ */
+static u32 hwirq_to_reg_set(unsigned long hwirq)
+{
+ return (hwirq / (NR_HW_IRQS * IRQS_PER_IDX));
+}
+
+static u32 hwirq_to_group(unsigned long hwirq)
+{
+ return (hwirq % NR_HW_IRQS);
+}
+
+static u32 hwirq_to_msi_data(unsigned long hwirq)
+{
+ return ((hwirq / NR_HW_IRQS) % IRQS_PER_IDX);
+}
+
+static void xgene_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ struct xgene_msi *msi = irq_data_get_irq_chip_data(data);
+ u32 reg_set = hwirq_to_reg_set(data->hwirq);
+ u32 group = hwirq_to_group(data->hwirq);
+ u64 target_addr = msi->msi_addr + (((8 * group) + reg_set) << 16);
+
+ msg->address_hi = upper_32_bits(target_addr);
+ msg->address_lo = lower_32_bits(target_addr);
+ msg->data = hwirq_to_msi_data(data->hwirq);
+}
+
+/*
+ * X-Gene v1 only has 16 MSI GIC IRQs for 2048 MSI vectors. To maintain
+ * the expected behaviour of .set_affinity for each MSI interrupt, the 16
+ * MSI GIC IRQs are statically allocated to 8 X-Gene v1 cores (2 GIC IRQs
+ * for each core). The MSI vector is moved fom 1 MSI GIC IRQ to another
+ * MSI GIC IRQ to steer its MSI interrupt to correct X-Gene v1 core. As a
+ * consequence, the total MSI vectors that X-Gene v1 supports will be
+ * reduced to 256 (2048/8) vectors.
+ */
+static int hwirq_to_cpu(unsigned long hwirq)
+{
+ return (hwirq % xgene_msi_ctrl.num_cpus);
+}
+
+static unsigned long hwirq_to_canonical_hwirq(unsigned long hwirq)
+{
+ return (hwirq - hwirq_to_cpu(hwirq));
+}
+
+static int xgene_msi_set_affinity(struct irq_data *irqdata,
+ const struct cpumask *mask, bool force)
+{
+ int target_cpu = cpumask_first(mask);
+ int curr_cpu;
+
+ curr_cpu = hwirq_to_cpu(irqdata->hwirq);
+ if (curr_cpu == target_cpu)
+ return IRQ_SET_MASK_OK_DONE;
+
+ /* Update MSI number to target the new CPU */
+ irqdata->hwirq = hwirq_to_canonical_hwirq(irqdata->hwirq) + target_cpu;
+
+ return IRQ_SET_MASK_OK;
+}
+
+static struct irq_chip xgene_msi_bottom_irq_chip = {
+ .name = "MSI",
+ .irq_set_affinity = xgene_msi_set_affinity,
+ .irq_compose_msi_msg = xgene_compose_msi_msg,
+};
+
+static int xgene_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct xgene_msi *msi = domain->host_data;
+ int msi_irq;
+
+ mutex_lock(&msi->bitmap_lock);
+
+ msi_irq = bitmap_find_next_zero_area(msi->bitmap, NR_MSI_VEC, 0,
+ msi->num_cpus, 0);
+ if (msi_irq < NR_MSI_VEC)
+ bitmap_set(msi->bitmap, msi_irq, msi->num_cpus);
+ else
+ msi_irq = -ENOSPC;
+
+ mutex_unlock(&msi->bitmap_lock);
+
+ if (msi_irq < 0)
+ return msi_irq;
+
+ irq_domain_set_info(domain, virq, msi_irq,
+ &xgene_msi_bottom_irq_chip, domain->host_data,
+ handle_simple_irq, NULL, NULL);
+
+ return 0;
+}
+
+static void xgene_irq_domain_free(struct irq_domain *domain,
+ unsigned int virq, unsigned int nr_irqs)
+{
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+ struct xgene_msi *msi = irq_data_get_irq_chip_data(d);
+ u32 hwirq;
+
+ mutex_lock(&msi->bitmap_lock);
+
+ hwirq = hwirq_to_canonical_hwirq(d->hwirq);
+ bitmap_clear(msi->bitmap, hwirq, msi->num_cpus);
+
+ mutex_unlock(&msi->bitmap_lock);
+
+ irq_domain_free_irqs_parent(domain, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops msi_domain_ops = {
+ .alloc = xgene_irq_domain_alloc,
+ .free = xgene_irq_domain_free,
+};
+
+static int xgene_allocate_domains(struct xgene_msi *msi)
+{
+ msi->inner_domain = irq_domain_add_linear(NULL, NR_MSI_VEC,
+ &msi_domain_ops, msi);
+ if (!msi->inner_domain)
+ return -ENOMEM;
+
+ msi->msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(msi->node),
+ &xgene_msi_domain_info,
+ msi->inner_domain);
+
+ if (!msi->msi_domain) {
+ irq_domain_remove(msi->inner_domain);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void xgene_free_domains(struct xgene_msi *msi)
+{
+ if (msi->msi_domain)
+ irq_domain_remove(msi->msi_domain);
+ if (msi->inner_domain)
+ irq_domain_remove(msi->inner_domain);
+}
+
+static int xgene_msi_init_allocator(struct xgene_msi *xgene_msi)
+{
+ int size = BITS_TO_LONGS(NR_MSI_VEC) * sizeof(long);
+
+ xgene_msi->bitmap = kzalloc(size, GFP_KERNEL);
+ if (!xgene_msi->bitmap)
+ return -ENOMEM;
+
+ mutex_init(&xgene_msi->bitmap_lock);
+
+ xgene_msi->msi_groups = kcalloc(NR_HW_IRQS,
+ sizeof(struct xgene_msi_group),
+ GFP_KERNEL);
+ if (!xgene_msi->msi_groups)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void xgene_msi_isr(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct xgene_msi_group *msi_groups;
+ struct xgene_msi *xgene_msi;
+ unsigned int virq;
+ int msir_index, msir_val, hw_irq;
+ u32 intr_index, grp_select, msi_grp;
+
+ chained_irq_enter(chip, desc);
+
+ msi_groups = irq_desc_get_handler_data(desc);
+ xgene_msi = msi_groups->msi;
+ msi_grp = msi_groups->msi_grp;
+
+ /*
+ * MSIINTn (n is 0..F) indicates if there is a pending MSI interrupt
+ * If bit x of this register is set (x is 0..7), one or more interupts
+ * corresponding to MSInIRx is set.
+ */
+ grp_select = xgene_msi_int_read(xgene_msi, msi_grp);
+ while (grp_select) {
+ msir_index = ffs(grp_select) - 1;
+ /*
+ * Calculate MSInIRx address to read to check for interrupts
+ * (refer to termination address and data assignment
+ * described in xgene_compose_msi_msg() )
+ */
+ msir_val = xgene_msi_ir_read(xgene_msi, msi_grp, msir_index);
+ while (msir_val) {
+ intr_index = ffs(msir_val) - 1;
+ /*
+ * Calculate MSI vector number (refer to the termination
+ * address and data assignment described in
+ * xgene_compose_msi_msg function)
+ */
+ hw_irq = (((msir_index * IRQS_PER_IDX) + intr_index) *
+ NR_HW_IRQS) + msi_grp;
+ /*
+ * As we have multiple hw_irq that maps to single MSI,
+ * always look up the virq using the hw_irq as seen from
+ * CPU0
+ */
+ hw_irq = hwirq_to_canonical_hwirq(hw_irq);
+ virq = irq_find_mapping(xgene_msi->inner_domain, hw_irq);
+ WARN_ON(!virq);
+ if (virq != 0)
+ generic_handle_irq(virq);
+ msir_val &= ~(1 << intr_index);
+ }
+ grp_select &= ~(1 << msir_index);
+
+ if (!grp_select) {
+ /*
+ * We handled all interrupts happened in this group,
+ * resample this group MSI_INTx register in case
+ * something else has been made pending in the meantime
+ */
+ grp_select = xgene_msi_int_read(xgene_msi, msi_grp);
+ }
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static enum cpuhp_state pci_xgene_online;
+
+static int xgene_msi_remove(struct platform_device *pdev)
+{
+ struct xgene_msi *msi = platform_get_drvdata(pdev);
+
+ if (pci_xgene_online)
+ cpuhp_remove_state(pci_xgene_online);
+ cpuhp_remove_state(CPUHP_PCI_XGENE_DEAD);
+
+ kfree(msi->msi_groups);
+
+ kfree(msi->bitmap);
+ msi->bitmap = NULL;
+
+ xgene_free_domains(msi);
+
+ return 0;
+}
+
+static int xgene_msi_hwirq_alloc(unsigned int cpu)
+{
+ struct xgene_msi *msi = &xgene_msi_ctrl;
+ struct xgene_msi_group *msi_group;
+ cpumask_var_t mask;
+ int i;
+ int err;
+
+ for (i = cpu; i < NR_HW_IRQS; i += msi->num_cpus) {
+ msi_group = &msi->msi_groups[i];
+ if (!msi_group->gic_irq)
+ continue;
+
+ irq_set_chained_handler(msi_group->gic_irq,
+ xgene_msi_isr);
+ err = irq_set_handler_data(msi_group->gic_irq, msi_group);
+ if (err) {
+ pr_err("failed to register GIC IRQ handler\n");
+ return -EINVAL;
+ }
+ /*
+ * Statically allocate MSI GIC IRQs to each CPU core.
+ * With 8-core X-Gene v1, 2 MSI GIC IRQs are allocated
+ * to each core.
+ */
+ if (alloc_cpumask_var(&mask, GFP_KERNEL)) {
+ cpumask_clear(mask);
+ cpumask_set_cpu(cpu, mask);
+ err = irq_set_affinity(msi_group->gic_irq, mask);
+ if (err)
+ pr_err("failed to set affinity for GIC IRQ");
+ free_cpumask_var(mask);
+ } else {
+ pr_err("failed to alloc CPU mask for affinity\n");
+ err = -EINVAL;
+ }
+
+ if (err) {
+ irq_set_chained_handler_and_data(msi_group->gic_irq,
+ NULL, NULL);
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+static int xgene_msi_hwirq_free(unsigned int cpu)
+{
+ struct xgene_msi *msi = &xgene_msi_ctrl;
+ struct xgene_msi_group *msi_group;
+ int i;
+
+ for (i = cpu; i < NR_HW_IRQS; i += msi->num_cpus) {
+ msi_group = &msi->msi_groups[i];
+ if (!msi_group->gic_irq)
+ continue;
+
+ irq_set_chained_handler_and_data(msi_group->gic_irq, NULL,
+ NULL);
+ }
+ return 0;
+}
+
+static const struct of_device_id xgene_msi_match_table[] = {
+ {.compatible = "apm,xgene1-msi"},
+ {},
+};
+
+static int xgene_msi_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+ int rc, irq_index;
+ struct xgene_msi *xgene_msi;
+ int virt_msir;
+ u32 msi_val, msi_idx;
+
+ xgene_msi = &xgene_msi_ctrl;
+
+ platform_set_drvdata(pdev, xgene_msi);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ xgene_msi->msi_regs = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(xgene_msi->msi_regs)) {
+ dev_err(&pdev->dev, "no reg space\n");
+ rc = PTR_ERR(xgene_msi->msi_regs);
+ goto error;
+ }
+ xgene_msi->msi_addr = res->start;
+ xgene_msi->node = pdev->dev.of_node;
+ xgene_msi->num_cpus = num_possible_cpus();
+
+ rc = xgene_msi_init_allocator(xgene_msi);
+ if (rc) {
+ dev_err(&pdev->dev, "Error allocating MSI bitmap\n");
+ goto error;
+ }
+
+ rc = xgene_allocate_domains(xgene_msi);
+ if (rc) {
+ dev_err(&pdev->dev, "Failed to allocate MSI domain\n");
+ goto error;
+ }
+
+ for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) {
+ virt_msir = platform_get_irq(pdev, irq_index);
+ if (virt_msir < 0) {
+ dev_err(&pdev->dev, "Cannot translate IRQ index %d\n",
+ irq_index);
+ rc = virt_msir;
+ goto error;
+ }
+ xgene_msi->msi_groups[irq_index].gic_irq = virt_msir;
+ xgene_msi->msi_groups[irq_index].msi_grp = irq_index;
+ xgene_msi->msi_groups[irq_index].msi = xgene_msi;
+ }
+
+ /*
+ * MSInIRx registers are read-to-clear; before registering
+ * interrupt handlers, read all of them to clear spurious
+ * interrupts that may occur before the driver is probed.
+ */
+ for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) {
+ for (msi_idx = 0; msi_idx < IDX_PER_GROUP; msi_idx++)
+ msi_val = xgene_msi_ir_read(xgene_msi, irq_index,
+ msi_idx);
+ /* Read MSIINTn to confirm */
+ msi_val = xgene_msi_int_read(xgene_msi, irq_index);
+ if (msi_val) {
+ dev_err(&pdev->dev, "Failed to clear spurious IRQ\n");
+ rc = -EINVAL;
+ goto error;
+ }
+ }
+
+ rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/xgene:online",
+ xgene_msi_hwirq_alloc, NULL);
+ if (rc < 0)
+ goto err_cpuhp;
+ pci_xgene_online = rc;
+ rc = cpuhp_setup_state(CPUHP_PCI_XGENE_DEAD, "pci/xgene:dead", NULL,
+ xgene_msi_hwirq_free);
+ if (rc)
+ goto err_cpuhp;
+
+ dev_info(&pdev->dev, "APM X-Gene PCIe MSI driver loaded\n");
+
+ return 0;
+
+err_cpuhp:
+ dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
+error:
+ xgene_msi_remove(pdev);
+ return rc;
+}
+
+static struct platform_driver xgene_msi_driver = {
+ .driver = {
+ .name = "xgene-msi",
+ .of_match_table = xgene_msi_match_table,
+ },
+ .probe = xgene_msi_probe,
+ .remove = xgene_msi_remove,
+};
+
+static int __init xgene_pcie_msi_init(void)
+{
+ return platform_driver_register(&xgene_msi_driver);
+}
+subsys_initcall(xgene_pcie_msi_init);
generated by cgit v1.2.3 (git 2.46.0) at 2025-11-04 01:52:00 +0000