From: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>

ARM GICv2m specification extends GICv2 to support MSI(-X) with
a new set of register frame. This patch introduces support for
the non-secure GICv2m register frame. Currently, GICV2m is available
in certain version of GIC-400.

The patch introduces a new property in ARM gic binding, the v2m subnode.
It is optional.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Marc Zyngier <marc.zyng...@arm.com>
Cc: Jason Cooper <ja...@lakedaemon.net>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
---
 Documentation/devicetree/bindings/arm/gic.txt |  39 ++++
 drivers/irqchip/Kconfig                       |   7 +
 drivers/irqchip/Makefile                      |   1 +
 drivers/irqchip/irq-gic-v2m.c                 | 261 ++++++++++++++++++++++++++
 drivers/irqchip/irq-gic.c                     |  88 ++++++---
 drivers/irqchip/irq-gic.h                     |  51 +++++
 6 files changed, 419 insertions(+), 28 deletions(-)
 create mode 100644 drivers/irqchip/irq-gic-v2m.c
 create mode 100644 drivers/irqchip/irq-gic.h

diff --git a/Documentation/devicetree/bindings/arm/gic.txt 
b/Documentation/devicetree/bindings/arm/gic.txt
index c7d2fa1..a461591 100644
--- a/Documentation/devicetree/bindings/arm/gic.txt
+++ b/Documentation/devicetree/bindings/arm/gic.txt
@@ -96,3 +96,42 @@ Example:
                      <0x2c006000 0x2000>;
                interrupts = <1 9 0xf04>;
        };
+
+
+* GICv2m extension for MSI/MSI-x support (Optional)
+
+Certain revision of GIC-400 supports MSI/MSI-x via V2M register frame.
+This is enabled by specifying v2m sub-node.
+
+Required properties:
+
+- msi-controller : Identifies the node as an MSI controller.
+
+- reg : GICv2m MSI interface register base and size
+
+Example:
+
+       interrupt-controller@e1101000 {
+               compatible = "arm,gic-400";
+               #interrupt-cells = <3>;
+               #address-cells = <2>;
+               #size-cells = <2>;
+               interrupt-controller;
+               interrupts = <1 8 0xf04>;
+               ranges = <0 0 0 0xe1100000 0 0x100000>;
+               reg = <0x0 0xe1110000 0 0x01000>,
+                     <0x0 0xe112f000 0 0x02000>,
+                     <0x0 0xe1140000 0 0x10000>,
+                     <0x0 0xe1160000 0 0x10000>;
+               v2m0 {
+                       msi-controller;
+                       reg = <0x0 0x80000 0 0x1000>;
+               };
+
+               ....
+
+               v2mN {
+                       msi-controller;
+                       reg = <0x0 0x90000 0 0x1000>;
+               };
+       };
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index b8632bf..ddb31ee 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -7,6 +7,13 @@ config ARM_GIC
        select IRQ_DOMAIN
        select MULTI_IRQ_HANDLER
 
+config ARM_GIC_V2M
+       bool
+       select IRQ_DOMAIN
+       select MULTI_IRQ_HANDLER
+       depends on ARM_GIC
+       depends on PCI && PCI_MSI
+
 config GIC_NON_BANKED
        bool
 
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 73052ba..3bda951 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_ARCH_SUNXI)              += irq-sun4i.o
 obj-$(CONFIG_ARCH_SUNXI)               += irq-sunxi-nmi.o
 obj-$(CONFIG_ARCH_SPEAR3XX)            += spear-shirq.o
 obj-$(CONFIG_ARM_GIC)                  += irq-gic.o irq-gic-common.o
+obj-$(CONFIG_ARM_GIC_V2M)              += irq-gic-v2m.o
 obj-$(CONFIG_ARM_GIC_V3)               += irq-gic-v3.o irq-gic-common.o
 obj-$(CONFIG_ARM_NVIC)                 += irq-nvic.o
 obj-$(CONFIG_ARM_VIC)                  += irq-vic.o
diff --git a/drivers/irqchip/irq-gic-v2m.c b/drivers/irqchip/irq-gic-v2m.c
new file mode 100644
index 0000000..499bfb9
--- /dev/null
+++ b/drivers/irqchip/irq-gic-v2m.c
@@ -0,0 +1,261 @@
+/*
+ * ARM GIC v2m MSI(-X) support
+ * Support for Message Signaled Interrupts for systems that
+ * implement ARM Generic Interrupt Controller: GICv2m.
+ *
+ * Copyright (C) 2014 Advanced Micro Devices, Inc.
+ * Authors: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com>
+ *          Harish Kasiviswanathan <harish.kasiviswanat...@amd.com>
+ *          Brandon Anderson <brandon.ander...@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#define pr_fmt(fmt) "GICv2m: " fmt
+
+#include <linux/bitmap.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "irqchip.h"
+#include "irq-gic.h"
+
+/*
+* MSI_TYPER:
+*     [31:26] Reserved
+*     [25:16] lowest SPI assigned to MSI
+*     [15:10] Reserved
+*     [9:0]   Numer of SPIs assigned to MSI
+*/
+#define V2M_MSI_TYPER                  0x008
+#define V2M_MSI_TYPER_BASE_SHIFT       16
+#define V2M_MSI_TYPER_BASE_MASK                0x3FF
+#define V2M_MSI_TYPER_NUM_MASK         0x3FF
+#define V2M_MSI_SETSPI_NS              0x040
+#define V2M_MIN_SPI                    32
+#define V2M_MAX_SPI                    1019
+
+/*
+ * alloc_msi_irq - Allocate MSIs from available MSI bitmap.
+ * @data: Pointer to v2m_data
+ * @nvec: Number of interrupts to allocate
+ * @irq: Pointer to the allocated irq
+ *
+ * Allocates interrupts only if the contiguous range of MSIs
+ * with specified nvec are available. Otherwise return the number
+ * of available interrupts. If none are available, then returns -ENOENT.
+ */
+static int alloc_msi_irq(struct v2m_data *data, int nvec, int *irq)
+{
+       int size = data->nr_spis;
+       int next = size, i = nvec, ret;
+
+       /* We should never allocate more than available nr_spis */
+       if (i >= size)
+               i = size;
+
+       spin_lock(&data->msi_cnt_lock);
+
+       for (; i > 0; i--) {
+               next = bitmap_find_next_zero_area(data->bm,
+                                       size, 0, i, 0);
+               if (next < size)
+                       break;
+       }
+
+       if (i != nvec) {
+               ret = i ? : -ENOENT;
+       } else {
+               bitmap_set(data->bm, next, nvec);
+               *irq = data->spi_start + next;
+               ret = 0;
+       }
+
+       spin_unlock(&data->msi_cnt_lock);
+
+       return ret;
+}
+
+static void gicv2m_teardown_msi_irq(struct msi_chip *chip, unsigned int irq)
+{
+       int pos;
+       struct v2m_data *data = container_of(chip, struct v2m_data, msi_chip);
+
+       spin_lock(&data->msi_cnt_lock);
+
+       pos = irq - data->spi_start;
+       if (pos >= 0 && pos < data->nr_spis)
+               bitmap_clear(data->bm, pos, 1);
+
+       spin_unlock(&data->msi_cnt_lock);
+}
+
+static int gicv2m_setup_msi_irq(struct msi_chip *chip,
+                               struct pci_dev *pdev,
+                               struct msi_desc *desc)
+{
+       int irq, avail;
+       struct msi_msg msg;
+       phys_addr_t addr;
+       struct v2m_data *data = container_of(chip, struct v2m_data, msi_chip);
+
+       if (!desc) {
+               dev_err(&pdev->dev,
+                       "GICv2m: MSI setup failed. Invalid msi descriptor\n");
+               return -EINVAL;
+       }
+
+       avail = alloc_msi_irq(data, 1, &irq);
+       if (avail != 0) {
+               dev_err(&pdev->dev,
+                       "GICv2m: MSI setup failed. Cannnot allocate IRQ\n");
+               return -ENOSPC;
+       }
+
+       irq_set_chip_data(irq, chip);
+       irq_set_msi_desc(irq, desc);
+       irq_set_irq_type(irq, IRQ_TYPE_EDGE_RISING);
+
+       addr = data->res.start + V2M_MSI_SETSPI_NS;
+       msg.address_hi = (u32)(addr >> 32);
+       msg.address_lo = (u32)(addr);
+       msg.data = irq;
+       write_msi_msg(irq, &msg);
+
+       return 0;
+}
+
+static void gicv2m_mask_irq(struct irq_data *d)
+{
+       gic_mask_irq(d);
+       if (d->msi_desc)
+               mask_msi_irq(d);
+}
+
+static void gicv2m_unmask_irq(struct irq_data *d)
+{
+       gic_unmask_irq(d);
+       if (d->msi_desc)
+               unmask_msi_irq(d);
+}
+
+#ifdef CONFIG_OF
+
+static int __init
+v2m_init(struct device_node *node, struct v2m_data *v2m,
+                 struct resource *res)
+{
+       int ret;
+       unsigned int typer;
+
+       v2m->msi_chip.owner = THIS_MODULE;
+       v2m->msi_chip.of_node = node;
+       v2m->msi_chip.setup_irq = gicv2m_setup_msi_irq;
+       v2m->msi_chip.teardown_irq = gicv2m_teardown_msi_irq;
+       ret = of_pci_msi_chip_add(&v2m->msi_chip);
+       if (ret) {
+               pr_info("Failed to add msi_chip.\n");
+               return ret;
+       }
+
+       v2m->base = ioremap(res->start, resource_size(res));
+       if (!v2m->base) {
+               pr_err("Failed to map GICv2m resource\n");
+               return -EINVAL;
+       }
+
+       memcpy(&v2m->res, res, sizeof(struct resource));
+
+       typer = readl_relaxed(v2m->base + V2M_MSI_TYPER);
+       if (!typer) {
+               pr_warn("Failed to read V2M_MSI_TYPER register\n");
+               return -EINVAL;
+       }
+
+       v2m->spi_start = (typer >> V2M_MSI_TYPER_BASE_SHIFT) &
+                               V2M_MSI_TYPER_BASE_MASK;
+       v2m->nr_spis = typer & V2M_MSI_TYPER_NUM_MASK;
+       if ((v2m->spi_start < V2M_MIN_SPI) || (v2m->nr_spis >= V2M_MAX_SPI)) {
+                       pr_err("Invalid MSI_TYPER (%#x)\n", typer);
+                       return -EINVAL;
+       }
+
+       v2m->bm = kzalloc(sizeof(long) * BITS_TO_LONGS(v2m->nr_spis),
+                         GFP_KERNEL);
+       if (!v2m->bm) {
+               pr_err("Failed to allocate MSI bitmap\n");
+               return -ENOMEM;
+       }
+
+       spin_lock_init(&v2m->msi_cnt_lock);
+
+       pr_info("SPI range [%d:%d]\n",
+               v2m->spi_start, (v2m->spi_start + v2m->nr_spis));
+
+       return 0;
+}
+
+int __init gicv2m_of_init(struct device_node *node,
+                         struct gic_chip_data *gic,
+                         struct irq_chip *v2m_chip)
+{
+       int ret = 0;
+       struct v2m_data *v2m;
+       struct resource res;
+       struct device_node *child = NULL;
+
+       INIT_LIST_HEAD(&gic->v2m_list);
+
+       for (;;) {
+               child = of_get_next_child(node, child);
+               if (!child)
+                       break;
+
+               if (!of_find_property(child, "msi-controller", NULL))
+                       continue;
+
+               ret = of_address_to_resource(child, 0, &res);
+               if (ret) {
+                       pr_err("Failed to allocate v2m resource.\n");
+                       break;
+               }
+
+               v2m = kzalloc(sizeof(struct v2m_data), GFP_KERNEL);
+               if (!v2m) {
+                       pr_err("Failed to allocate struct v2m_data.\n");
+                       return -ENOMEM;
+               }
+
+               ret = v2m_init(child, v2m, &res);
+               if (ret)
+                       break;
+
+               v2m->gic = gic;
+
+               pr_info(" %s: [%lx : %lx]\n", child->name,
+                       (unsigned long)res.start, (unsigned long)res.end);
+
+               list_add_tail(&v2m->list, &gic->v2m_list);
+       }
+
+       if (ret && list_empty(&gic->v2m_list)) {
+               pr_err("MSI resource not found\n");
+               return -EINVAL;
+       }
+
+       v2m_chip->irq_mask = gicv2m_mask_irq;
+       v2m_chip->irq_unmask = gicv2m_unmask_irq;
+
+       return ret;
+}
+
+#endif /* CONFIG_OF */
diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 4b959e6..f490599 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -46,30 +46,9 @@
 #include <asm/smp_plat.h>
 
 #include "irq-gic-common.h"
+#include "irq-gic.h"
 #include "irqchip.h"
 
-union gic_base {
-       void __iomem *common_base;
-       void __percpu * __iomem *percpu_base;
-};
-
-struct gic_chip_data {
-       union gic_base dist_base;
-       union gic_base cpu_base;
-#ifdef CONFIG_CPU_PM
-       u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
-       u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
-       u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
-       u32 __percpu *saved_ppi_enable;
-       u32 __percpu *saved_ppi_conf;
-#endif
-       struct irq_domain *domain;
-       unsigned int gic_irqs;
-#ifdef CONFIG_GIC_NON_BANKED
-       void __iomem *(*get_base)(union gic_base *);
-#endif
-};
-
 static DEFINE_RAW_SPINLOCK(irq_controller_lock);
 
 /*
@@ -131,15 +110,36 @@ static inline void gic_set_base_accessor(struct 
gic_chip_data *data,
 #define gic_set_base_accessor(d, f)
 #endif
 
+static inline
+struct gic_chip_data *irq_data_get_gic_chip_data(struct irq_data *d)
+{
+       struct gic_chip_data *gic_data;
+       struct msi_chip *mchip;
+       struct v2m_data *v2mdat;
+
+       /*
+        * For MSI, irq_data.chip_data points to struct msi_chip.
+        * For non-MSI, irq_data.chip_data points to struct gic_chip_data.
+        */
+       if (d->msi_desc) {
+               mchip = irq_data_get_irq_chip_data(d);
+               v2mdat = container_of(mchip, struct v2m_data, msi_chip);
+               gic_data = v2mdat->gic;
+       } else {
+               gic_data = irq_data_get_irq_chip_data(d);
+       }
+       return gic_data;
+}
+
 static inline void __iomem *gic_dist_base(struct irq_data *d)
 {
-       struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
+       struct gic_chip_data *gic_data = irq_data_get_gic_chip_data(d);
        return gic_data_dist_base(gic_data);
 }
 
 static inline void __iomem *gic_cpu_base(struct irq_data *d)
 {
-       struct gic_chip_data *gic_data = irq_data_get_irq_chip_data(d);
+       struct gic_chip_data *gic_data = irq_data_get_gic_chip_data(d);
        return gic_data_cpu_base(gic_data);
 }
 
@@ -151,7 +151,7 @@ static inline unsigned int gic_irq(struct irq_data *d)
 /*
  * Routines to acknowledge, disable and enable interrupts
  */
-static void gic_mask_irq(struct irq_data *d)
+void gic_mask_irq(struct irq_data *d)
 {
        u32 mask = 1 << (gic_irq(d) % 32);
 
@@ -162,7 +162,7 @@ static void gic_mask_irq(struct irq_data *d)
        raw_spin_unlock(&irq_controller_lock);
 }
 
-static void gic_unmask_irq(struct irq_data *d)
+void gic_unmask_irq(struct irq_data *d)
 {
        u32 mask = 1 << (gic_irq(d) % 32);
 
@@ -325,6 +325,15 @@ static struct irq_chip gic_chip = {
        .irq_set_wake           = gic_set_wake,
 };
 
+static struct irq_chip v2m_chip = {
+       .name                   = "GICv2m",
+       .irq_eoi                = gic_eoi_irq,
+       .irq_set_type           = gic_set_type,
+#ifdef CONFIG_SMP
+       .irq_set_affinity       = gic_set_affinity,
+#endif
+};
+
 void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
 {
        if (gic_nr >= MAX_GIC_NR)
@@ -767,6 +776,24 @@ void __init gic_init_physaddr(struct device_node *node)
 static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
                                irq_hw_number_t hw)
 {
+       struct gic_chip_data *gic = d->host_data;
+       struct v2m_data *v2m;
+
+       irq_set_chip_data(irq, gic);
+
+#ifdef CONFIG_ARM_GIC_V2M
+       list_for_each_entry(v2m, &gic->v2m_list, list) {
+               if (hw >= v2m->spi_start &&
+                   hw <  v2m->spi_start + v2m->nr_spis) {
+
+                       irq_set_chip_and_handler(irq, &v2m_chip,
+                                        handle_fasteoi_irq);
+                       set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+                       return 0;
+               }
+       }
+#endif
+
        if (hw < 32) {
                irq_set_percpu_devid(irq);
                irq_set_chip_and_handler(irq, &gic_chip,
@@ -779,7 +806,6 @@ static int gic_irq_domain_map(struct irq_domain *d, 
unsigned int irq,
 
                gic_routable_irq_domain_ops->map(d, irq, hw);
        }
-       irq_set_chip_data(irq, d->host_data);
        return 0;
 }
 
@@ -996,7 +1022,7 @@ gic_of_init(struct device_node *node, struct device_node 
*parent)
        void __iomem *cpu_base;
        void __iomem *dist_base;
        u32 percpu_offset;
-       int irq;
+       int irq, ret;
 
        if (WARN_ON(!node))
                return -ENODEV;
@@ -1010,6 +1036,12 @@ gic_of_init(struct device_node *node, struct device_node 
*parent)
        if (of_property_read_u32(node, "cpu-offset", &percpu_offset))
                percpu_offset = 0;
 
+       if (IS_ENABLED(CONFIG_ARM_GIC_V2M)) {
+               ret = gicv2m_of_init(node, &gic_data[gic_cnt], &v2m_chip);
+               if (ret)
+                       pr_warn("Warning: Failed to enable GICv2m support.\n");
+       }
+
        gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset, node);
        if (!gic_cnt)
                gic_init_physaddr(node);
diff --git a/drivers/irqchip/irq-gic.h b/drivers/irqchip/irq-gic.h
new file mode 100644
index 0000000..1f4a2b0
--- /dev/null
+++ b/drivers/irqchip/irq-gic.h
@@ -0,0 +1,51 @@
+#ifndef _IRQ_GIC_H_
+#define _IRQ_GIC_H_
+
+#include <linux/msi.h>
+#include <linux/pci.h>
+
+union gic_base {
+       void __iomem *common_base;
+       void __percpu * __iomem *percpu_base;
+};
+
+struct gic_chip_data;
+
+struct v2m_data {
+#ifdef CONFIG_ARM_GIC_V2M
+       struct list_head list;
+       spinlock_t msi_cnt_lock;
+       struct msi_chip msi_chip;
+       struct resource res;      /* GICv2m resource */
+       void __iomem *base;       /* GICv2m virt address */
+       unsigned int spi_start;   /* The SPI number that MSIs start */
+       unsigned int nr_spis;     /* The number of SPIs for MSIs */
+       unsigned long *bm;        /* MSI vector bitmap */
+       struct gic_chip_data *gic;
+#endif
+};
+
+struct gic_chip_data {
+       union gic_base dist_base;
+       union gic_base cpu_base;
+#ifdef CONFIG_CPU_PM
+       u32 saved_spi_enable[DIV_ROUND_UP(1020, 32)];
+       u32 saved_spi_conf[DIV_ROUND_UP(1020, 16)];
+       u32 saved_spi_target[DIV_ROUND_UP(1020, 4)];
+       u32 __percpu *saved_ppi_enable;
+       u32 __percpu *saved_ppi_conf;
+#endif
+       struct irq_domain *domain;
+       unsigned int gic_irqs;
+#ifdef CONFIG_GIC_NON_BANKED
+       void __iomem *(*get_base)(union gic_base *);
+#endif
+       struct list_head v2m_list;
+};
+
+void gic_mask_irq(struct irq_data *d);
+void gic_unmask_irq(struct irq_data *d);
+int gicv2m_of_init(struct device_node *node, struct gic_chip_data *gic,
+                  struct irq_chip *v2m_chip) __init;
+
+#endif /* _IRQ_GIC_H_ */
-- 
1.9.3

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