Re: [PATCH v2] ACPI: ARM Performance Monitoring Unit Table (APMT) initial support

Rafael J. Wysocki
2022-09-30T17:47:37Z

On Thu, Sep 29, 2022 at 2:29 AM Besar Wicaksono <bwicaksono@nvidia.com> wrote:
>
> ARM Performance Monitoring Unit Table describes the properties of PMU
> support in ARM-based system. The APMT table contains a list of nodes,
> each represents a PMU in the system that conforms to ARM CoreSight PMU
> architecture. The properties of each node include information required
> to access the PMU (e.g. MMIO base address, interrupt number) and also
> identification. For more detailed information, please refer to the
> specification below:
> * APMT: https://developer.arm.com/documentation/den0117/latest
> * ARM Coresight PMU:
> https://developer.arm.com/documentation/ihi0091/latest
>
> The initial support adds the detection of APMT table and generic
> infrastructure to create platform devices for ARM CoreSight PMUs.
> Similar to IORT the root pointer of APMT is preserved during runtime
> and each PMU platform device is given a pointer to the corresponding
> APMT node.
>
> Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

for the change in bus.c, but as a side note, it would be good to move
all of the ARM-specific initialization into one place, so it is not
necessary to touch bus.c every time a new piece of it is added.

> ---
>
> The patch applies on top of
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> master next-20220524
>
> Changes from v1:
> * Include acpi_apmt.h header file
> * Update the device name. Related driver patch:
> https://lore.kernel.org/linux-arm-kernel/20220928201830.45637-1-bwicaksono@nvidia.com/
> v1: https://lkml.org/lkml/2022/4/19/1395
>
> arch/arm64/Kconfig | 1 +
> drivers/acpi/arm64/Kconfig | 3 +
> drivers/acpi/arm64/Makefile | 1 +
> drivers/acpi/arm64/apmt.c | 177 ++++++++++++++++++++++++++++++++++++
> drivers/acpi/bus.c | 2 +
> include/linux/acpi_apmt.h | 19 ++++
> 6 files changed, 203 insertions(+)
> create mode 100644 drivers/acpi/arm64/apmt.c
> create mode 100644 include/linux/acpi_apmt.h
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index aaeb70358979..dbcb09ee29dd 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1,6 +1,7 @@
> # SPDX-License-Identifier: GPL-2.0-only
> config ARM64
> def_bool y
> + select ACPI_APMT if ACPI
> select ACPI_CCA_REQUIRED if ACPI
> select ACPI_GENERIC_GSI if ACPI
> select ACPI_GTDT if ACPI
> diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
> index d4a72835f328..b3ed6212244c 100644
> --- a/drivers/acpi/arm64/Kconfig
> +++ b/drivers/acpi/arm64/Kconfig
> @@ -18,3 +18,6 @@ config ACPI_AGDI
> reset command.
>
> If set, the kernel parses AGDI table and listens for the command.
> +
> +config ACPI_APMT
> + bool
> diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> index 7b9e4045659d..e21a9e84e394 100644
> --- a/drivers/acpi/arm64/Makefile
> +++ b/drivers/acpi/arm64/Makefile
> @@ -2,4 +2,5 @@
> obj-$(CONFIG_ACPI_AGDI) += agdi.o
> obj-$(CONFIG_ACPI_IORT) += iort.o
> obj-$(CONFIG_ACPI_GTDT) += gtdt.o
> +obj-$(CONFIG_ACPI_APMT) += apmt.o
> obj-y += dma.o
> diff --git a/drivers/acpi/arm64/apmt.c b/drivers/acpi/arm64/apmt.c
> new file mode 100644
> index 000000000000..f55167ca51e7
> --- /dev/null
> +++ b/drivers/acpi/arm64/apmt.c
> @@ -0,0 +1,177 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ARM APMT table support.
> + * Design document number: ARM DEN0117.
> + *
> + * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
> + *
> + */
> +
> +#define pr_fmt(fmt) "ACPI: APMT: " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/acpi_apmt.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/platform_device.h>
> +
> +#define DEV_NAME "arm-cs-arch-pmu"
> +
> +/* There can be up to 3 resources: page 0 and 1 address, and interrupt. */
> +#define DEV_MAX_RESOURCE_COUNT 3
> +
> +/* Root pointer to the mapped APMT table */
> +static struct acpi_table_header *apmt_table;
> +
> +static int __init apmt_init_resources(struct resource *res,
> + struct acpi_apmt_node *node)
> +{
> + int irq, trigger;
> + int num_res = 0;
> +
> + res[num_res].start = node->base_address0;
> + res[num_res].end = node->base_address0 + SZ_4K - 1;
> + res[num_res].flags = IORESOURCE_MEM;
> +
> + num_res++;
> +
> + res[num_res].start = node->base_address1;
> + res[num_res].end = node->base_address1 + SZ_4K - 1;
> + res[num_res].flags = IORESOURCE_MEM;
> +
> + num_res++;
> +
> + if (node->ovflw_irq != 0) {
> + trigger = (node->ovflw_irq_flags & ACPI_APMT_OVFLW_IRQ_FLAGS_MODE);
> + trigger = (trigger == ACPI_APMT_OVFLW_IRQ_FLAGS_MODE_LEVEL) ?
> + ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
> + irq = acpi_register_gsi(NULL, node->ovflw_irq, trigger,
> + ACPI_ACTIVE_HIGH);
> +
> + if (irq <= 0) {
> + pr_warn("APMT could not register gsi hwirq %d\n", irq);
> + return num_res;
> + }
> +
> + res[num_res].start = irq;
> + res[num_res].end = irq;
> + res[num_res].flags = IORESOURCE_IRQ;
> +
> + num_res++;
> + }
> +
> + return num_res;
> +}
> +
> +/**
> + * apmt_add_platform_device() - Allocate a platform device for APMT node
> + * @node: Pointer to device ACPI APMT node
> + *
> + * Returns: 0 on success, <0 failure
> + */
> +static int __init apmt_add_platform_device(struct acpi_apmt_node *node,
> + struct fwnode_handle *fwnode)
> +{
> + struct platform_device *pdev;
> + int ret, count;
> + struct resource res[DEV_MAX_RESOURCE_COUNT];
> +
> + pdev = platform_device_alloc(DEV_NAME, PLATFORM_DEVID_AUTO);
> + if (!pdev)
> + return -ENOMEM;
> +
> + memset(res, 0, sizeof(res));
> +
> + count = apmt_init_resources(res, node);
> +
> + ret = platform_device_add_resources(pdev, res, count);
> + if (ret)
> + goto dev_put;
> +
> + /*
> + * Add a copy of APMT node pointer to platform_data to be used to
> + * retrieve APMT data information.
> + */
> + ret = platform_device_add_data(pdev, &node, sizeof(node));
> + if (ret)
> + goto dev_put;
> +
> + pdev->dev.fwnode = fwnode;
> +
> + ret = platform_device_add(pdev);
> +
> + if (ret)
> + goto dev_put;
> +
> + return 0;
> +
> +dev_put:
> + platform_device_put(pdev);
> +
> + return ret;
> +}
> +
> +static int __init apmt_init_platform_devices(void)
> +{
> + struct acpi_apmt_node *apmt_node;
> + struct acpi_table_apmt *apmt;
> + struct fwnode_handle *fwnode;
> + u64 offset, end;
> + int ret;
> +
> + /*
> + * apmt_table and apmt both point to the start of APMT table, but
> + * have different struct types
> + */
> + apmt = (struct acpi_table_apmt *)apmt_table;
> + offset = sizeof(*apmt);
> + end = apmt->header.length;
> +
> + while (offset < end) {
> + apmt_node = ACPI_ADD_PTR(struct acpi_apmt_node, apmt,
> + offset);
> +
> + fwnode = acpi_alloc_fwnode_static();
> + if (!fwnode)
> + return -ENOMEM;
> +
> + ret = apmt_add_platform_device(apmt_node, fwnode);
> + if (ret) {
> + acpi_free_fwnode_static(fwnode);
> + return ret;
> + }
> +
> + offset += apmt_node->length;
> + }
> +
> + return 0;
> +}
> +
> +void __init acpi_apmt_init(void)
> +{
> + acpi_status status;
> + int ret;
> +
> + /**
> + * APMT table nodes will be used at runtime after the apmt init,
> + * so we don't need to call acpi_put_table() to release
> + * the APMT table mapping.
> + */
> + status = acpi_get_table(ACPI_SIG_APMT, 0, &apmt_table);
> +
> + if (ACPI_FAILURE(status)) {
> + if (status != AE_NOT_FOUND) {
> + const char *msg = acpi_format_exception(status);
> +
> + pr_err("Failed to get APMT table, %s\n", msg);
> + }
> +
> + return;
> + }
> +
> + ret = apmt_init_platform_devices();
> + if (ret) {
> + pr_err("Failed to initialize APMT platform devices, ret: %d\n", ret);
> + acpi_put_table(apmt_table);
> + }
> +}
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 86fa61a21826..f9dc5b3d5c55 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -27,6 +27,7 @@
> #include <linux/dmi.h>
> #endif
> #include <linux/acpi_agdi.h>
> +#include <linux/acpi_apmt.h>
> #include <linux/acpi_iort.h>
> #include <linux/acpi_viot.h>
> #include <linux/pci.h>
> @@ -1411,6 +1412,7 @@ static int __init acpi_init(void)
> acpi_setup_sb_notify_handler();
> acpi_viot_init();
> acpi_agdi_init();
> + acpi_apmt_init();
> return 0;
> }
>
> diff --git a/include/linux/acpi_apmt.h b/include/linux/acpi_apmt.h
> new file mode 100644
> index 000000000000..40bd634d082f
> --- /dev/null
> +++ b/include/linux/acpi_apmt.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * ARM CoreSight PMU driver.
> + * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
> + *
> + */
> +
> +#ifndef __ACPI_APMT_H__
> +#define __ACPI_APMT_H__
> +
> +#include <linux/acpi.h>
> +
> +#ifdef CONFIG_ACPI_APMT
> +void acpi_apmt_init(void);
> +#else
> +static inline void acpi_apmt_init(void) { }
> +#endif /* CONFIG_ACPI_APMT */
> +
> +#endif /* __ACPI_APMT_H__ */
>
> base-commit: 09ce5091ff971cdbfd67ad84dc561ea27f10d67a
> --
> 2.17.1