From: Fu Wei fu.wei@linaro.org
Parse SBSA Generic Watchdog Structure in GTDT table of ACPI, and create a platform device with that information This platform device can be used by the ARM SBSA Generic Watchdog driver
Signed-off-by: Fu Wei fu.wei@linaro.org --- arch/arm64/kernel/acpi.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+)
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index 8b83955..1ed11fd 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -23,6 +23,7 @@ #include <linux/irqdomain.h> #include <linux/memblock.h> #include <linux/of_fdt.h> +#include <linux/platform_device.h> #include <linux/smp.h>
#include <asm/cputype.h> @@ -343,3 +344,138 @@ void __init acpi_gic_init(void)
early_acpi_os_unmap_memory((char *)table, tbl_size); } + +static int __init acpi_gtdt_import_sbsa_gwdt(struct acpi_gtdt_watchdog *wd, + int index) +{ + struct platform_device *pdev; + struct resource *res; + u32 gsi, flags; + int irq, trigger, polarity; + resource_size_t rf_base_phy, cf_base_phy; + int err = -ENOMEM; + + /* + * Get SBSA Generic Watchdog info + * from a Watchdog GT type structure in GTDT + */ + rf_base_phy = (resource_size_t)wd->refresh_frame_address; + cf_base_phy = (resource_size_t)wd->control_frame_address; + gsi = wd->timer_interrupt; + flags = wd->timer_flags; + + pr_info("GTDT: a Watchdog GT structure(0x%llx/0x%llx gsi:%u flags:0x%x)\n", + rf_base_phy, cf_base_phy, gsi, flags); + + if (!(rf_base_phy && cf_base_phy && gsi)) { + pr_err("GTDT: failed geting the device info.\n"); + return -EINVAL; + } + + trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE + : ACPI_LEVEL_SENSITIVE; + polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW + : ACPI_ACTIVE_HIGH; + irq = acpi_register_gsi(NULL, gsi, trigger, polarity); + if (irq < 0) { + pr_err("GTDT: failed to register GSI of the Watchdog GT.\n"); + return -EINVAL; + } + + pdev = platform_device_alloc("sbsa-gwdt", index); + if (!pdev) + goto err_unregister_gsi; + + res = kcalloc(3, sizeof(*res), GFP_KERNEL); + if (!res) + goto err_device_put; + + res[0].start = rf_base_phy; + res[0].end = rf_base_phy + SZ_4K - 1; + res[0].name = "refresh"; + res[0].flags = IORESOURCE_MEM; + + res[1].start = cf_base_phy; + res[1].end = cf_base_phy + SZ_4K - 1; + res[1].name = "control"; + res[1].flags = IORESOURCE_MEM; + + res[2].start = irq; + res[2].end = res[2].start; + res[2].name = "ws0"; + res[2].flags = IORESOURCE_IRQ; + + err = platform_device_add_resources(pdev, res, 3); + if (err) + goto err_free_res; + + err = platform_device_add(pdev); + if (err) + goto err_free_res; + + return 0; + +err_free_res: + kfree(res); +err_device_put: + platform_device_put(pdev); +err_unregister_gsi: + acpi_unregister_gsi(gsi); + + return err; +} + +/* Initialize SBSA generic Watchdog platform device info from GTDT */ +static int __init acpi_gtdt_sbsa_gwdt_init(struct acpi_table_header *table) +{ + struct acpi_table_gtdt *gtdt; + struct acpi_gtdt_header *header; + void *gtdt_subtable; + int i, gwdt_index; + int ret = 0; + + if (table->revision < 2) { + pr_info("GTDT: Revision:%d doesn't support Platform Timers.\n", + table->revision); + return 0; + } + + gtdt = container_of(table, struct acpi_table_gtdt, header); + if (!gtdt->platform_timer_count) { + pr_info("GTDT: No Platform Timer structures.\n"); + return 0; + } + + gtdt_subtable = (void *)gtdt + gtdt->platform_timer_offset; + + for (i = 0, gwdt_index = 0; i < gtdt->platform_timer_count; i++) { + if (gtdt_subtable > (void *)table + table->length) { + pr_err("GTDT: subtable pointer overflows, bad table\n"); + return -EINVAL; + } + header = (struct acpi_gtdt_header *)gtdt_subtable; + if (header->type == ACPI_GTDT_TYPE_WATCHDOG) { + ret = acpi_gtdt_import_sbsa_gwdt(gtdt_subtable, + gwdt_index); + if (ret) + pr_err("GTDT: failed to import subtable %d\n", + i); + else + gwdt_index++; + } + gtdt_subtable += header->length; + } + + return ret; +} + +/* Initialize the SBSA Generic Watchdog presented in GTDT */ +static int __init acpi_gtdt_init(void) +{ + if (acpi_disabled) + return 0; + + return acpi_table_parse(ACPI_SIG_GTDT, acpi_gtdt_sbsa_gwdt_init); +} + +arch_initcall(acpi_gtdt_init);