[PATCH v8 08/21] dt / chosen: Add linux, uefi-stub-generated-dtb property

Hanjun Guo
2015-02-02T12:45:36Z

When system supporting both DT and ACPI but firmware providing
no dtb, we can use this linux,uefi-stub-generated-dtb property
to let kernel know that we can try ACPI configuration data even
if no "acpi=force" is passed in early parameters.

CC: Mark Rutland <mark.rutland@arm.com>
CC: Jonathan Corbet <corbet@lwn.net>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Leif Lindholm <leif.lindholm@linaro.org>
CC: Grant Likely <grant.likely@linaro.org>
CC: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
---
Documentation/arm/uefi.txt | 3 +++
arch/arm64/include/asm/acpi.h | 1 +
arch/arm64/kernel/setup.c | 30 ++++++++++++++++++++++++++++++
drivers/firmware/efi/libstub/fdt.c | 8 ++++++++
4 files changed, 42 insertions(+)

diff --git a/Documentation/arm/uefi.txt b/Documentation/arm/uefi.txt
index d60030a..5f86eae 100644
--- a/Documentation/arm/uefi.txt
+++ b/Documentation/arm/uefi.txt
@@ -60,5 +60,8 @@ linux,uefi-mmap-desc-ver | 32-bit | Version of the mmap descriptor format.
--------------------------------------------------------------------------------
linux,uefi-stub-kern-ver | string | Copy of linux_banner from build.
--------------------------------------------------------------------------------
+linux,uefi-stub-generated-dtb | bool | Indication for no DTB provided by
+ | | firmware.
+--------------------------------------------------------------------------------

For verbose debug messages, specify 'uefi_debug' on the kernel command line.
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 496c33b..9fcf632 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -49,6 +49,7 @@ static inline void arch_fix_phys_package_id(int num, u32 slot) { }

#else
static inline void disable_acpi(void) { }
+static inline void enable_acpi(void) { }
#endif /* CONFIG_ACPI */

#endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index fc4fb7b..510a681 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -371,6 +371,29 @@ static void __init request_standard_resources(void)
}
}

+static int __init dt_scan_chosen(unsigned long node, const char *uname,
+ int depth, void *data)
+{
+ const char *p;
+
+ if (depth != 1 || !data || (strcmp(uname, "chosen") != 0))
+ return 0;
+
+ p = of_get_flat_dt_prop(node, "linux,uefi-stub-generated-dtb", NULL);
+ *(bool *)data = p ? true : false;
+
+ return 1;
+}
+
+static bool __init is_uefi_stub_generated_dtb(void)
+{
+ bool flag = false;
+
+ of_scan_flat_dt(dt_scan_chosen, &flag);
+
+ return flag;
+}
+
u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID };

void __init setup_arch(char **cmdline_p)
@@ -399,6 +422,13 @@ void __init setup_arch(char **cmdline_p)
parse_early_param();

/*
+ * If no dtb provided by firmware, enable ACPI and give system a
+ * chance to boot with ACPI configuration data
+ */
+ if (is_uefi_stub_generated_dtb() && acpi_disabled)
+ enable_acpi();
+
+ /*
* Unmask asynchronous aborts after bringing up possible earlycon.
* (Report possible System Errors once we can report this occurred)
*/
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index c846a96..3777d50 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -154,6 +154,14 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
if (status)
goto fdt_set_fail;

+ /* Add a property to show the dtb is generated by uefi stub */
+ if (!orig_fdt) {
+ status = fdt_setprop(fdt, node,
+ "linux,uefi-stub-generated-dtb", NULL, 0);
+ if (status)
+ goto fdt_set_fail;
+ }
+
return EFI_SUCCESS;

fdt_set_fail:
--
1.9.1