[PATCH V3 0/1] RISCV_EFI_BOOT_PROTOCOL support in linux

[PATCH V3 0/1] RISCV_EFI_BOOT_PROTOCOL support in linux

[Sunil V L]

This patch adds support for getting the boot hart ID using new
RISCV_EFI_BOOT_PROTOCOL in linux efi stub. While there is an existing
solution of passing the boot hart ID through Device Tree, it doesn't work for
ACPI. Hence an EFI protocol protocol is recommended which works for both DT and ACPI
based platforms.

The frozen spec of this new protocol is available at
https://github.com/riscv-non-isa/riscv-uefi/releases/download/1.0-rc3/RISCV_UEFI_PROTOCOL-spec.pdf

This is tested in qemu with both u-boot and edk2.

Changes since V2:
  - Updated error message

Changes since V1:
  - Rebased to get the "Fix get_boot_hartid_from_fdt() return value"
    patch
  - Removed mixed_mode member
  - Separated return value and status.


Sunil V L (1):
  riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL

 drivers/firmware/efi/libstub/efistub.h    |  7 ++++++
 drivers/firmware/efi/libstub/riscv-stub.c | 29 +++++++++++++++++++----
 include/linux/efi.h                       |  1 +
 3 files changed, 32 insertions(+), 5 deletions(-)

-- 
2.25.1

[PATCH V3 1/1] riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL

[Sunil V L]

This patch adds the support for getting the boot hart ID in
Linux EFI stub using RISCV_EFI_BOOT_PROTOCOL. This protocol
is preferred method over existing DT based solution since it
works irrespective of DT or ACPI.

The specification of the protocol is hosted at:
https://github.com/riscv-non-isa/riscv-uefi

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 drivers/firmware/efi/libstub/efistub.h    |  7 ++++++
 drivers/firmware/efi/libstub/riscv-stub.c | 29 +++++++++++++++++++----
 include/linux/efi.h                       |  1 +
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index edb77b0621ea..aced62a0907e 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -720,6 +720,13 @@ union efi_tcg2_protocol {
 	} mixed_mode;
 };
 
+struct riscv_efi_boot_protocol {
+	u64 revision;
+
+	efi_status_t (__efiapi * get_boot_hartid)(struct riscv_efi_boot_protocol *this,
+						  size_t *boot_hartid);
+};
+
 typedef union efi_load_file_protocol efi_load_file_protocol_t;
 typedef union efi_load_file_protocol efi_load_file2_protocol_t;
 
diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c
index 9c460843442f..012504f6f9a4 100644
--- a/drivers/firmware/efi/libstub/riscv-stub.c
+++ b/drivers/firmware/efi/libstub/riscv-stub.c
@@ -23,7 +23,7 @@
 
 typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long);
 
-static u32 hartid;
+static size_t hartid;
 
 static int get_boot_hartid_from_fdt(void)
 {
@@ -47,14 +47,33 @@ static int get_boot_hartid_from_fdt(void)
 	return 0;
 }
 
+static efi_status_t get_boot_hartid_from_efi(void)
+{
+	efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
+	efi_status_t status;
+	struct riscv_efi_boot_protocol *boot_protocol;
+
+	status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
+			     (void **)&boot_protocol);
+	if (status == EFI_SUCCESS) {
+		status = efi_call_proto(boot_protocol,
+					get_boot_hartid, &hartid);
+	}
+	return status;
+}
+
 efi_status_t check_platform_features(void)
 {
 	int ret;
+	efi_status_t status;
 
-	ret = get_boot_hartid_from_fdt();
-	if (ret) {
-		efi_err("/chosen/boot-hartid missing or invalid!\n");
-		return EFI_UNSUPPORTED;
+	status = get_boot_hartid_from_efi();
+	if (status != EFI_SUCCESS) {
+		ret = get_boot_hartid_from_fdt();
+		if (ret) {
+			efi_err("Failed to get boot hartid!\n");
+			return EFI_UNSUPPORTED;
+		}
 	}
 	return EFI_SUCCESS;
 }
diff --git a/include/linux/efi.h b/include/linux/efi.h
index ccd4d3f91c98..9822c730207c 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -380,6 +380,7 @@ void efi_native_runtime_setup(void);
 #define EFI_CONSOLE_OUT_DEVICE_GUID		EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4,  0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)
 #define APPLE_PROPERTIES_PROTOCOL_GUID		EFI_GUID(0x91bd12fe, 0xf6c3, 0x44fb,  0xa5, 0xb7, 0x51, 0x22, 0xab, 0x30, 0x3a, 0xe0)
 #define EFI_TCG2_PROTOCOL_GUID			EFI_GUID(0x607f766c, 0x7455, 0x42be,  0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
+#define RISCV_EFI_BOOT_PROTOCOL_GUID		EFI_GUID(0xccd15fec, 0x6f73, 0x4eec,  0x83, 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)
 #define EFI_LOAD_FILE_PROTOCOL_GUID		EFI_GUID(0x56ec3091, 0x954c, 0x11d2,  0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
 #define EFI_LOAD_FILE2_PROTOCOL_GUID		EFI_GUID(0x4006c0c1, 0xfcb3, 0x403e,  0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d)
 #define EFI_RT_PROPERTIES_TABLE_GUID		EFI_GUID(0xeb66918a, 0x7eef, 0x402a,  0x84, 0x2e, 0x93, 0x1d, 0x21, 0xc3, 0x8a, 0xe9)
-- 
2.25.1