acpi/arm64: Add GTDT table parse driver

This patch adds support for parsing arch timer info in GTDT,
provides some kernel APIs to parse all the PPIs and
always-on info in GTDT and export them.

By this driver, we can simplify arm_arch_timer drivers, and
separate the ACPI GTDT knowledge from it.

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3741859..7e2baec 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -2,6 +2,7 @@ config ARM64
        def_bool y
        select ACPI_CCA_REQUIRED if ACPI
        select ACPI_GENERIC_GSI if ACPI
+       select ACPI_GTDT if ACPI
        select ACPI_REDUCED_HARDWARE_ONLY if ACPI
        select ACPI_MCFG if ACPI
        select ACPI_SPCR_TABLE if ACPI

diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
index 4616da4..5a6f80f 100644 (file)
--- a/drivers/acpi/arm64/Kconfig
+++ b/drivers/acpi/arm64/Kconfig
@@ -4,3 +4,6 @@
 
 config ACPI_IORT
        bool
+
+config ACPI_GTDT
+       bool

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
index 72331f2..1017def 100644 (file)
--- a/drivers/acpi/arm64/Makefile
+++ b/drivers/acpi/arm64/Makefile
@@ -1 +1,2 @@
 obj-$(CONFIG_ACPI_IORT)        += iort.o
+obj-$(CONFIG_ACPI_GTDT)        += gtdt.o

diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c
new file mode 100644 (file)
index 0000000..3d95af8
--- /dev/null
+++ b/drivers/acpi/arm64/gtdt.c
@@ -0,0 +1,157 @@
+/*
+ * ARM Specific GTDT table Support
+ *
+ * Copyright (C) 2016, Linaro Ltd.
+ * Author: Daniel Lezcano <daniel.lezcano@linaro.org>
+ *         Fu Wei <fu.wei@linaro.org>
+ *         Hanjun Guo <hanjun.guo@linaro.org>
+ *
+ * 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/acpi.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+
+#include <clocksource/arm_arch_timer.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) "ACPI GTDT: " fmt
+
+/**
+ * struct acpi_gtdt_descriptor - Store the key info of GTDT for all functions
+ * @gtdt:      The pointer to the struct acpi_table_gtdt of GTDT table.
+ * @gtdt_end:  The pointer to the end of GTDT table.
+ * @platform_timer:    The pointer to the start of Platform Timer Structure
+ *
+ * The struct store the key info of GTDT table, it should be initialized by
+ * acpi_gtdt_init.
+ */
+struct acpi_gtdt_descriptor {
+       struct acpi_table_gtdt *gtdt;
+       void *gtdt_end;
+       void *platform_timer;
+};
+
+static struct acpi_gtdt_descriptor acpi_gtdt_desc __initdata;
+
+static int __init map_gt_gsi(u32 interrupt, u32 flags)
+{
+       int trigger, polarity;
+
+       trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+                       : ACPI_LEVEL_SENSITIVE;
+
+       polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+                       : ACPI_ACTIVE_HIGH;
+
+       return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/**
+ * acpi_gtdt_map_ppi() - Map the PPIs of per-cpu arch_timer.
+ * @type:      the type of PPI.
+ *
+ * Note: Secure state is not managed by the kernel on ARM64 systems.
+ * So we only handle the non-secure timer PPIs,
+ * ARCH_TIMER_PHYS_SECURE_PPI is treated as invalid type.
+ *
+ * Return: the mapped PPI value, 0 if error.
+ */
+int __init acpi_gtdt_map_ppi(int type)
+{
+       struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+
+       switch (type) {
+       case ARCH_TIMER_PHYS_NONSECURE_PPI:
+               return map_gt_gsi(gtdt->non_secure_el1_interrupt,
+                                 gtdt->non_secure_el1_flags);
+       case ARCH_TIMER_VIRT_PPI:
+               return map_gt_gsi(gtdt->virtual_timer_interrupt,
+                                 gtdt->virtual_timer_flags);
+
+       case ARCH_TIMER_HYP_PPI:
+               return map_gt_gsi(gtdt->non_secure_el2_interrupt,
+                                 gtdt->non_secure_el2_flags);
+       default:
+               pr_err("Failed to map timer interrupt: invalid type.\n");
+       }
+
+       return 0;
+}
+
+/**
+ * acpi_gtdt_c3stop() - Got c3stop info from GTDT according to the type of PPI.
+ * @type:      the type of PPI.
+ *
+ * Return: true if the timer HW state is lost when a CPU enters an idle state,
+ * false otherwise
+ */
+bool __init acpi_gtdt_c3stop(int type)
+{
+       struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
+
+       switch (type) {
+       case ARCH_TIMER_PHYS_NONSECURE_PPI:
+               return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
+
+       case ARCH_TIMER_VIRT_PPI:
+               return !(gtdt->virtual_timer_flags & ACPI_GTDT_ALWAYS_ON);
+
+       case ARCH_TIMER_HYP_PPI:
+               return !(gtdt->non_secure_el2_flags & ACPI_GTDT_ALWAYS_ON);
+
+       default:
+               pr_err("Failed to get c3stop info: invalid type.\n");
+       }
+
+       return false;
+}
+
+/**
+ * acpi_gtdt_init() - Get the info of GTDT table to prepare for further init.
+ * @table:                     The pointer to GTDT table.
+ * @platform_timer_count:      It points to a integer variable which is used
+ *                             for storing the number of platform timers.
+ *                             This pointer could be NULL, if the caller
+ *                             doesn't need this info.
+ *
+ * Return: 0 if success, -EINVAL if error.
+ */
+int __init acpi_gtdt_init(struct acpi_table_header *table,
+                         int *platform_timer_count)
+{
+       void *platform_timer;
+       struct acpi_table_gtdt *gtdt;
+
+       gtdt = container_of(table, struct acpi_table_gtdt, header);
+       acpi_gtdt_desc.gtdt = gtdt;
+       acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
+       acpi_gtdt_desc.platform_timer = NULL;
+       if (platform_timer_count)
+               *platform_timer_count = 0;
+
+       if (table->revision < 2) {
+               pr_warn("Revision:%d doesn't support Platform Timers.\n",
+                       table->revision);
+               return 0;
+       }
+
+       if (!gtdt->platform_timer_count) {
+               pr_debug("No Platform Timer.\n");
+               return 0;
+       }
+
+       platform_timer = (void *)gtdt + gtdt->platform_timer_offset;
+       if (platform_timer < (void *)table + sizeof(struct acpi_table_gtdt)) {
+               pr_err(FW_BUG "invalid timer data.\n");
+               return -EINVAL;
+       }
+       acpi_gtdt_desc.platform_timer = platform_timer;
+       if (platform_timer_count)
+               *platform_timer_count = gtdt->platform_timer_count;
+
+       return 0;
+}

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 9b05886..4b5c146 100644 (file)
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -595,6 +595,12 @@ enum acpi_reconfig_event  {
 int acpi_reconfig_notifier_register(struct notifier_block *nb);
 int acpi_reconfig_notifier_unregister(struct notifier_block *nb);
 
+#ifdef CONFIG_ACPI_GTDT
+int acpi_gtdt_init(struct acpi_table_header *table, int *platform_timer_count);
+int acpi_gtdt_map_ppi(int type);
+bool acpi_gtdt_c3stop(int type);
+#endif
+
 #else  /* !CONFIG_ACPI */
 
 #define acpi_disabled 1