From: Rob Clark <robdclark@xxxxxxxxxxxx>
On snapdragon aarch64 laptops, a 'UEFIDisplayInfo' variable is provided
to communicate some information about the display. Crutially it has the
panel-id, so the appropriate panel driver can be selected. Read this
out and stash in /chosen/panel-id so that display driver can use it to
pick the appropriate panel.
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
drivers/firmware/efi/libstub/arm-stub.c | 49 +++++++++++++++++++++++++
drivers/firmware/efi/libstub/efistub.h | 2 +
drivers/firmware/efi/libstub/fdt.c | 9 +++++
3 files changed, 60 insertions(+)
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 04e6ecd72cd9..999813252e0d 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -69,6 +69,53 @@ static struct screen_info *setup_graphics(efi_system_table_t *sys_table_arg)
return si;
}
+/*
+ * We (at least currently) don't care about most of the fields, just
+ * panel_id:
+ */
+struct mdp_disp_info {
+ u32 version_info;
+ u32 pad0[9];
+ u32 panel_id;
+ u32 pad1[17];
+};
+
+#define MDP_DISP_INFO_VERSION_MAGIC 0xaa
+
+static void get_panel_id(efi_system_table_t *sys_table_arg,
+ unsigned long fdt_addr)
+{
+ efi_guid_t gop_proto = EFI_GRAPHICS_OUTPUT_PROTOCOL_GUID;
+ efi_status_t status;
+ struct mdp_disp_info *disp_info;
+ unsigned long size = 0;
+
+ status = efi_call_runtime(get_variable, L"UEFIDisplayInfo",
+ &gop_proto, NULL, &size, NULL);
+ if (status == EFI_NOT_FOUND)
+ return;
+
+ status = efi_call_early(allocate_pool, EFI_LOADER_DATA, size,
+ (void **)&disp_info);
+ if (status != EFI_SUCCESS)
+ return;
+
+ status = efi_call_runtime(get_variable, L"UEFIDisplayInfo",
+ &gop_proto, NULL, &size, disp_info);
+ if (status != EFI_SUCCESS)
+ goto cleanup;
+
+ if ((disp_info->version_info >> 16) != MDP_DISP_INFO_VERSION_MAGIC)
+ goto cleanup;
+
+ efi_printk(sys_table_arg, "found a panel-id!\n");
+
+ set_chosen_panel_id(fdt_addr, disp_info->panel_id);
+
+cleanup:
+ efi_call_early(free_pool, disp_info);
+}
+
void install_memreserve_table(efi_system_table_t *sys_table_arg)
{
struct linux_efi_memreserve *rsv;
@@ -229,6 +276,8 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
if (!fdt_addr)
pr_efi(sys_table, "Generating empty DTB\n");
+ get_panel_id(sys_table, fdt_addr);
+
status = handle_cmdline_files(sys_table, image, cmdline_ptr, "initrd=",
efi_get_max_initrd_addr(dram_base,
*image_addr),
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 1b1dfcaa6fb9..8832cb9a7a40 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -39,6 +39,8 @@ void efi_char16_printk(efi_system_table_t *, efi_char16_t *);
unsigned long get_dram_base(efi_system_table_t *sys_table_arg);
+void set_chosen_panel_id(unsigned long fdt_addr, unsigned panel_id);
+
efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
void *handle,
unsigned long *new_fdt_addr,
diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
index 5440ba17a1c5..cb6ea160a40a 100644
--- a/drivers/firmware/efi/libstub/fdt.c
+++ b/drivers/firmware/efi/libstub/fdt.c
@@ -200,6 +200,15 @@ static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
return EFI_SUCCESS;
}
+void set_chosen_panel_id(unsigned long fdt_addr, unsigned panel_id)
+{
+ void *fdt = (void *)fdt_addr;
+ int node = fdt_subnode_offset(fdt, 0, "chosen");
+ u32 fdt_val32 = cpu_to_fdt32(panel_id);
+
+ fdt_setprop_var(fdt, node, "panel-id", fdt_val32);
+}
+
#ifndef EFI_FDT_ALIGN
# define EFI_FDT_ALIGN EFI_PAGE_SIZE
#endif
--
2.20.1
