1 files changed, 583 insertions, 0 deletions

diff --git a/kernel/drivers/pci/host/pci-xgene-msi.c b/kernel/drivers/pci/host/pci-xgene-msi.c
new file mode 100644
index 000000000..a6456b578
--- /dev/null
+++ b/kernel/drivers/pci/host/pci-xgene-msi.c
@@ -0,0 +1,583 @@
+/*
+ * APM X-Gene MSI Driver
+ *
+ * Copyright (c) 2014, Applied Micro Circuits Corporation
+ * Author: Tanmay Inamdar <tinamdar@apm.com>
+ *	   Duc Dang <dhdang@apm.com>
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * 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.
+ */
+#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 int xgene_msi_remove(struct platform_device *pdev)
+{
+	int virq, i;
+	struct xgene_msi *msi = platform_get_drvdata(pdev);
+
+	for (i = 0; i < NR_HW_IRQS; i++) {
+		virq = msi->msi_groups[i].gic_irq;
+		if (virq != 0)
+			irq_set_chained_handler_and_data(virq, NULL, NULL);
+	}
+	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 void 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);
+	}
+}
+
+static int xgene_msi_cpu_callback(struct notifier_block *nfb,
+				  unsigned long action, void *hcpu)
+{
+	unsigned cpu = (unsigned long)hcpu;
+
+	switch (action) {
+	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
+		xgene_msi_hwirq_alloc(cpu);
+		break;
+	case CPU_DEAD:
+	case CPU_DEAD_FROZEN:
+		xgene_msi_hwirq_free(cpu);
+		break;
+	default:
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block xgene_msi_cpu_notifier = {
+	.notifier_call = xgene_msi_cpu_callback,
+};
+
+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;
+	unsigned int cpu;
+	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 = -EINVAL;
+		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 = -EINVAL;
+			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;
+		}
+	}
+
+	cpu_notifier_register_begin();
+
+	for_each_online_cpu(cpu)
+		if (xgene_msi_hwirq_alloc(cpu)) {
+			dev_err(&pdev->dev, "failed to register MSI handlers\n");
+			cpu_notifier_register_done();
+			goto error;
+		}
+
+	rc = __register_hotcpu_notifier(&xgene_msi_cpu_notifier);
+	if (rc) {
+		dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
+		cpu_notifier_register_done();
+		goto error;
+	}
+
+	cpu_notifier_register_done();
+
+	dev_info(&pdev->dev, "APM X-Gene PCIe MSI driver loaded\n");
+
+	return 0;
+
+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);