Re: [PATCH 1/2 V4] irqchip: gic: Add supports for ARM GICv2m MSI(-X)

[Marc Zyngier <marc.zyngier@arm.com>]

Hi Suravee,

On Wed, Aug 13 2014 at  4:00:40 pm BST, "suravee.suthikulpanit@amd.com" <suravee.suthikulpanit@amd.com> wrote:
> From: Suravee Suthikulpanit <Suravee.Suthikulpanit@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.

This is starting to look better. See below my comments.

> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
> Cc: Mark Rutland <Mark.Rutland@arm.com>
> Cc: Marc Zyngier <Marc.Zyngier@arm.com>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Catalin Marinas <Catalin.Marinas@arm.com>
> Cc: Will Deacon <Will.Deacon@arm.com>
> ---
>  Documentation/devicetree/bindings/arm/gic.txt |  32 ++++
>  drivers/irqchip/Kconfig                       |   7 +
>  drivers/irqchip/Makefile                      |   1 +
>  drivers/irqchip/irq-gic-v2m.c                 | 215 ++++++++++++++++++++++++++
>  drivers/irqchip/irq-gic.c                     |  75 +++++----
>  drivers/irqchip/irq-gic.h                     |  48 ++++++
>  6 files changed, 348 insertions(+), 30 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 5573c08..8a64179 100644
> --- a/Documentation/devicetree/bindings/arm/gic.txt
> +++ b/Documentation/devicetree/bindings/arm/gic.txt
> @@ -95,3 +95,35 @@ 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>;
> +               v2m {
> +                       msi-controller;
> +                       reg = <0x0 0x80000 0 0x1000>;
> +               };
> +       };
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 4e230e7..9aa5edc 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..1ac0ace
> --- /dev/null
> +++ b/drivers/irqchip/irq-gic-v2m.c
> @@ -0,0 +1,215 @@
> +/*
> + * ARM GIC v2m MSI(-X) support
> + * Support for Message Signalelled Interrupts for systems that
> + * implement ARM Generic Interrupt Controller: GICv2m.
> + *
> + * Copyright (C) 2014 Advanced Micro Devices, Inc.
> + * Authors: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> + *          Harish Kasiviswanathan <harish.kasiviswanathan@amd.com>
> + *          Brandon Anderson <brandon.anderson@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.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pci.h>
> +#include <linux/irq.h>
> +#include <linux/spinlock.h>
> +#include <linux/slab.h>
> +#include <linux/of_address.h>
> +#include <linux/of_pci.h>
> +#include <linux/bitmap.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 avaialbe 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 avail, irq = 0;
> +       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);
> +}
> +
> +static struct irq_chip gicv2m_chip;
> +
> +#ifdef CONFIG_OF

Is there any reason why this should be guarded by CONFIG_OF? Surely the
v2m capability should only be enabled if OF is.

> +int __init
> +gicv2m_of_init(struct device_node *node, struct gic_chip_data *gic)
> +{
> +       int ret;
> +       unsigned int val;
> +       struct v2m_data *v2m = &gic->v2m_data;
> +
> +       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("GICv2m: Failed to add msi_chip.\n");
> +               return ret;
> +       }
> +
> +       if (of_address_to_resource(node, 0, &v2m->res)) {
> +               pr_err("GICv2m: Failed locate GICv2m MSI register frame\n");
> +               return -EINVAL;
> +       }
> +
> +       v2m->base = of_iomap(node, 0);
> +       if (!v2m->base) {
> +               pr_err("GICv2m: Failed to map GIC MSI registers\n");
> +               return -EINVAL;
> +       }
> +
> +       val = readl_relaxed(v2m->base + V2M_MSI_TYPER);
> +       if (!val) {
> +               pr_warn("GICv2m: Failed to read V2M_MSI_TYPER register\n");
> +               return -EINVAL;
> +       }
> +
> +       v2m->spi_start = (val >> V2M_MSI_TYPER_BASE_SHIFT) &
> +                               V2M_MSI_TYPER_BASE_MASK;
> +       v2m->nr_spis = val & V2M_MSI_TYPER_NUM_MASK;
> +       if ((v2m->spi_start < V2M_MIN_SPI) || (v2m->nr_spis >= V2M_MAX_SPI)) {
> +                       pr_err("GICv2m: Invalid MSI_TYPER (%#x)\n", val);
> +                       return -EINVAL;
> +       }
> +
> +       v2m->bm = kzalloc(sizeof(long) * BITS_TO_LONGS(v2m->nr_spis),
> +                         GFP_KERNEL);
> +       if (!v2m->bm) {
> +               pr_err("GICv2m: Failed to allocate MSI bitmap\n");
> +               return -ENOMEM;
> +       }
> +
> +       spin_lock_init(&v2m->msi_cnt_lock);
> +
> +       pr_info("GICv2m: SPI range [%d:%d]\n",
> +               v2m->spi_start, (v2m->spi_start + v2m->nr_spis));
> +
> +       memcpy(&gicv2m_chip, gic->irq_chip, sizeof(struct irq_chip));
> +       gicv2m_chip.name = "GICv2m",
> +       gicv2m_chip.irq_mask = gicv2m_mask_irq;
> +       gicv2m_chip.irq_unmask = gicv2m_unmask_irq;
> +       gic->irq_chip = &gicv2m_chip;

I liked it until this last line. You're overriding the irq_chip for the
whole GIC. I was expecting you'd only use it for the MSI range
(basically return a range to the caller, together with your brand new
irq_chip).

> +
> +       return 0;
> +}
> +
> +#endif /* CONFIG_OF */
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 508b815..b175ccf 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -47,30 +47,9 @@
>  #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);
>
>  /*
> @@ -132,15 +111,36 @@ 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 = container_of(v2mdat, struct gic_chip_data, v2m_data);
> +       } 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);
>  }
>
> @@ -152,7 +152,7 @@ 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);
>
> @@ -163,7 +163,7 @@ 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);
>
> @@ -768,19 +768,21 @@ 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;
> +
>         if (hw < 32) {
>                 irq_set_percpu_devid(irq);
> -               irq_set_chip_and_handler(irq, &gic_chip,
> +               irq_set_chip_and_handler(irq, gic->irq_chip,
>                                          handle_percpu_devid_irq);
>                 set_irq_flags(irq, IRQF_VALID | IRQF_NOAUTOEN);
>         } else {
> -               irq_set_chip_and_handler(irq, &gic_chip,
> +               irq_set_chip_and_handler(irq, gic->irq_chip,
>                                          handle_fasteoi_irq);

And here you should discriminate on whether this is MSI or not, based on
the range you got from above.

>                 set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
>
>                 gic_routable_irq_domain_ops->map(d, irq, hw);
>         }
> -       irq_set_chip_data(irq, d->host_data);
> +       irq_set_chip_data(irq, gic);
>         return 0;
>  }
>
> @@ -992,10 +994,11 @@ static int gic_cnt __initdata;
>  static int __init
>  gic_of_init(struct device_node *node, struct device_node *parent)
>  {
> +       struct device_node *child;
>         void __iomem *cpu_base;
>         void __iomem *dist_base;
>         u32 percpu_offset;
> -       int irq;
> +       int irq, ret;
>
>         if (WARN_ON(!node))
>                 return -ENODEV;
> @@ -1009,6 +1012,16 @@ gic_of_init(struct device_node *node, struct device_node *parent)
>         if (of_property_read_u32(node, "cpu-offset", &percpu_offset))
>                 percpu_offset = 0;
>
> +       gic_data[gic_cnt].irq_chip = &gic_chip;
> +
> +       /* Currently, we only support one v2m subnode. */
> +       child = of_get_child_by_name(node, "v2m");

If you only support one v2m node, then you should also enforce it for
potential secondaty GICs (just probing it for gic_cnt == 0 should be
enough).

> +       if (child) {
> +               ret = gicv2m_of_init(child, &gic_data[gic_cnt]);
> +               if (ret)
> +                       return ret;
> +       }
> +
>         gic_init_bases(gic_cnt, -1, dist_base, cpu_base, percpu_offset, node);
>         if (!gic_cnt)
>                 gic_init_physaddr(node);
> @@ -1020,6 +1033,8 @@ gic_of_init(struct device_node *node, struct device_node *parent)
>         gic_cnt++;
>         return 0;
>  }
> +
> +IRQCHIP_DECLARE(gic_400, "arm,gic-400", gic_of_init);
>  IRQCHIP_DECLARE(cortex_a15_gic, "arm,cortex-a15-gic", gic_of_init);
>  IRQCHIP_DECLARE(cortex_a9_gic, "arm,cortex-a9-gic", gic_of_init);
>  IRQCHIP_DECLARE(msm_8660_qgic, "qcom,msm-8660-qgic", gic_of_init);
> diff --git a/drivers/irqchip/irq-gic.h b/drivers/irqchip/irq-gic.h
> new file mode 100644
> index 0000000..2ec6bc3
> --- /dev/null
> +++ b/drivers/irqchip/irq-gic.h
> @@ -0,0 +1,48 @@
> +#ifndef _IRQ_GIC_H_
> +#define _IRQ_GIC_H_
> +
> +#include <linux/msi.h>
> +
> +union gic_base {
> +       void __iomem *common_base;
> +       void __percpu * __iomem *percpu_base;
> +};
> +
> +#ifdef CONFIG_ARM_GIC_V2M
> +struct v2m_data {
> +       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 */
> +};
> +#endif

So if you put the #ifdef/#endif *inside* the v2m_data structure...

> +
> +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 irq_chip *irq_chip;
> +#ifdef CONFIG_ARM_GIC_V2M
> +       struct v2m_data v2m_data;
> +#endif

... you can then get rid of this #ifdef/#endif.

> +};
> +
> +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) __init;
> +
> +#endif /* _IRQ_GIC_H_ */
> --
> 1.9.0
>
>

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny.