[PATCH 3/4 V3] irqchip: gic: Add supports for ARM GICv2m MSI(-X)

Marc Zyngier
2014-07-30T14:57:47Z

On Thu, Jul 10 2014 at 12:05:03 am BST, "suravee.suthikulpanit at amd.com" <suravee.suthikulpanit@amd.com> wrote:

Hi Suravee,

> From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>
> ARM GICv2m specification extends GICv2 to support MSI(-X) with
> a new set of register frames. This patch introduces support for
> the non-secure GICv2m register frame.
>
> The driver currently matchs "arm,gic-400-plus" in device tree binding,
> which implements GICv2m.
>
> The "msi-controller" keyword in ARM GIC devicetree binding is used to indentify
> GIC driver that it should enable MSI(-X) support, The region of GICv2m MSI
> register frame is specified using the register frame index 4 in the device tree.
> MSI support is optional.
>
> Each GIC maintains an "msi_chip" structure. To discover the msi_chip,
> PCI host driver can do the following:
>
> struct device_node *gic_node = of_irq_find_parent(pdev->dev.of_node);
> pcie_bus->msi_chip = of_pci_find_msi_chip_by_node(gic_node);
>
> 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>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
> ---
> Documentation/devicetree/bindings/arm/gic.txt | 20 +-
> arch/arm64/Kconfig | 1 +
> drivers/irqchip/Kconfig | 7 +
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-gic-v2m.c | 251 ++++++++++++++++++++++++++
> drivers/irqchip/irq-gic-v2m.h | 13 ++
> drivers/irqchip/irq-gic.c | 23 ++-
> drivers/irqchip/irq-gic.h | 31 +++-
> 8 files changed, 334 insertions(+), 13 deletions(-)
> create mode 100644 drivers/irqchip/irq-gic-v2m.c
> create mode 100644 drivers/irqchip/irq-gic-v2m.h
>
> diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
> index 5573c08..d2eea0b 100644
> --- a/Documentation/devicetree/bindings/arm/gic.txt
> +++ b/Documentation/devicetree/bindings/arm/gic.txt
> @@ -12,11 +12,14 @@ Main node required properties:
>
> - compatible : should be one of:
> "arm,gic-400"
> + "arm,gic-400-v2m"
> "arm,cortex-a15-gic"
> "arm,cortex-a9-gic"
> "arm,cortex-a7-gic"
> "arm,arm11mp-gic"
> +
> - interrupt-controller : Identifies the node as an interrupt controller
> +
> - #interrupt-cells : Specifies the number of cells needed to encode an
> interrupt source. The type shall be a <u32> and the value shall be 3.
>
> @@ -37,9 +40,16 @@ Main node required properties:
> the 8 possible cpus attached to the GIC. A bit set to '1' indicated
> the interrupt is wired to that CPU. Only valid for PPI interrupts.
>
> -- reg : Specifies base physical address(s) and size of the GIC registers. The
> - first region is the GIC distributor register base and size. The 2nd region is
> - the GIC cpu interface register base and size.
> +- reg : Specifies base physical address(s) and size of the GIC register frames.
> +
> + Region | Description
> + Index |
> + -------------------------------------------------------------------
> + 0 | GIC distributor register base and size
> + 1 | GIC cpu interface register base and size
> + 2 | VGIC interface control register base and size (Optional)
> + 3 | VGIC CPU interface register base and size (Optional)
> + 4 | GICv2m MSI interface register base and size (Optional)

Given that the v2m block is somehow bolted on the side of a standard
GICv2, I'd rather see it as a subnode of the main GIC.

Then you could directly call into the v2m layer to initialize it,
instead of the odd "reverse probing" you're using here...

> Optional
> - interrupts : Interrupt source of the parent interrupt controller on
> @@ -55,6 +65,10 @@ Optional
> by a crossbar/multiplexer preceding the GIC. The GIC irq
> input line is assigned dynamically when the corresponding
> peripheral's crossbar line is mapped.
> +
> +- msi-controller : Identifies the node as an MSI controller.
> + (Required for GICv2m)
> +
> Example:
>
> intc: interrupt-controller at fff11000 {
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index be52492..0f9b11d 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -9,6 +9,7 @@ config ARM64
> select ARM_AMBA
> select ARM_ARCH_TIMER
> select ARM_GIC
> + select ARM_GIC_V2M if (PCI && PCI_MSI)
> select ARM_GIC_V3
> select BUILDTIME_EXTABLE_SORT
> select CLONE_BACKWARDS
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 7f0c2a3..274910d 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 c57e642..09c035a 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -16,6 +16,7 @@ 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..e54ca1d
> --- /dev/null
> +++ b/drivers/irqchip/irq-gic-v2m.c
> @@ -0,0 +1,251 @@
> +/*
> + * 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
> +
> +#define GIC_OF_MSIV2M_RANGE_INDEX 4
> +
> +/*
> + * 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 struct v2m_data *to_v2m_data(struct msi_chip *chip)
> +{
> + struct gic_chip_data *gic = container_of(chip, struct gic_chip_data,
> + msi_chip);
> + return &gic->v2m_data;
> +}
> +
> +static void gicv2m_teardown_msi_irq(struct msi_chip *chip, unsigned int irq)
> +{
> + int pos;
> + struct v2m_data *data = to_v2m_data(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 = to_v2m_data(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 int __init
> +gicv2m_msi_init(struct device_node *node, struct v2m_data *v2m)
> +{
> + unsigned int val;
> +
> + if (of_address_to_resource(node, GIC_OF_MSIV2M_RANGE_INDEX,
> + &v2m->res)) {
> + pr_err("GICv2m: Failed locate GICv2m MSI register frame\n");
> + return -EINVAL;
> + }
> +
> + v2m->base = of_iomap(node, GIC_OF_MSIV2M_RANGE_INDEX);
> + 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));
> +
> + return 0;
> +}

This function is assuming that you will only see one single MSI frame
here. Is there any chance that there would be more than one in a system?

> +
> +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 = {
> + .name = "GICv2m",
> + .irq_mask = gicv2m_mask_irq,
> + .irq_unmask = gicv2m_unmask_irq,
> + .irq_eoi = gic_eoi_irq,
> + .irq_set_type = gic_set_type,
> + .irq_retrigger = gic_retrigger,

I think you can loose the retrigger here.

> +#ifdef CONFIG_SMP
> + .irq_set_affinity = gic_set_affinity,
> +#endif
> +#ifdef CONFIG_PM
> + .irq_set_wake = gic_set_wake,
> +#endif
> +};
> +
> +#ifdef CONFIG_OF
> +static int __init
> +gicv2m_of_init(struct device_node *node, struct device_node *parent)
> +{
> + struct gic_chip_data *gic;
> + int ret;
> +
> + ret = _gic_of_init(node, parent, &gicv2m_chip, &gic);
> + if (ret) {
> + pr_err("GICv2m: Failed to initialize GIC\n");
> + return ret;
> + }
> +
> + gic->msi_chip.owner = THIS_MODULE;
> + gic->msi_chip.of_node = node;
> + gic->msi_chip.setup_irq = gicv2m_setup_msi_irq;
> + gic->msi_chip.teardown_irq = gicv2m_teardown_msi_irq;
> + ret = of_pci_msi_chip_add(&gic->msi_chip);
> + if (ret) {
> + /* MSI is optional and not supported here */
> + pr_info("GICv2m: MSI is not supported.\n");
> + return 0;
> + }
> +
> + ret = gicv2m_msi_init(node, &gic->v2m_data);
> + if (ret)
> + return ret;
> + return ret;
> +}
> +
> +IRQCHIP_DECLARE(arm_gic_400_v2m, "arm,gic-400-v2m", gicv2m_of_init);

So if you follow my advise of reversing your probing and call into the
v2m init from the main GIC driver, you could take a irq_chip as a
parameter, and use it to populate the v2m irq_chip, only overriding the
two methods that actually differ.

This would have the net effect of completely dropping patch #2, which
becomes effectively useless.

> +#endif /* CONFIG_OF */
> diff --git a/drivers/irqchip/irq-gic-v2m.h b/drivers/irqchip/irq-gic-v2m.h
> new file mode 100644
> index 0000000..2d93a87
> --- /dev/null
> +++ b/drivers/irqchip/irq-gic-v2m.h
> @@ -0,0 +1,13 @@
> +#ifndef _IRQ_GIC_V2M_H_
> +#define _IRQ_GIC_V2M_H_
> +
> +struct v2m_data {
> + spinlock_t msi_cnt_lock;
> + 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 /*_IRQ_GIC_V2M_H_*/
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 966e1d5..a054e0d 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -111,15 +111,34 @@ 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;
> +
> + /*
> + * 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);
> + gic_data = container_of(mchip, struct gic_chip_data, msi_chip);
> + } 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);
> }
>
> diff --git a/drivers/irqchip/irq-gic.h b/drivers/irqchip/irq-gic.h
> index a4beb4a..1c6547d 100644
> --- a/drivers/irqchip/irq-gic.h
> +++ b/drivers/irqchip/irq-gic.h
> @@ -8,6 +8,17 @@ union gic_base {
> void __percpu * __iomem *percpu_base;
> };
>
> +#ifdef CONFIG_ARM_GIC_V2M
> +struct v2m_data {
> + spinlock_t msi_cnt_lock;
> + 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
> +
> struct gic_chip_data {
> union gic_base dist_base;
> union gic_base cpu_base;
> @@ -20,12 +31,23 @@ struct gic_chip_data {
> #endif
> struct irq_domain *domain;
> unsigned int gic_irqs;
> - struct irq_chip *irq_chip;
> #ifdef CONFIG_GIC_NON_BANKED
> void __iomem *(*get_base)(union gic_base *);
> #endif
> + struct irq_chip *irq_chip;
> + struct msi_chip msi_chip;
> +#ifdef CONFIG_ARM_GIC_V2M
> + struct v2m_data v2m_data;
> +#endif

Why isn't msi_chip directly part of v2m_data? I think that would make
some of the code slightly clearer, and avoid polluting unsuspecting
architectures...

> };
>
> +#ifdef CONFIG_OF
> +int _gic_of_init(struct device_node *node,
> + struct device_node *parent,
> + struct irq_chip *chip,
> + struct gic_chip_data **gic) __init;
> +#endif
> +
> void gic_mask_irq(struct irq_data *d);
> void gic_unmask_irq(struct irq_data *d);
> void gic_eoi_irq(struct irq_data *d);
> @@ -42,11 +64,4 @@ int gic_set_affinity(struct irq_data *d,
> int gic_set_wake(struct irq_data *d, unsigned int on);
> #endif
>
> -#ifdef CONFIG_OF
> -int _gic_of_init(struct device_node *node,
> - struct device_node *parent,
> - struct irq_chip *chip,
> - struct gic_chip_data **gic) __init;
> -#endif
> -
> #endif /* _IRQ_GIC_H_ */

What is the purpose of this move?

Thanks,

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