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WDCIronportException: Internal
From:   Atish Patra <atish.patra@wdc.com>
To:     linux-kernel@vger.kernel.org
Cc:     Atish Patra <atish.patra@wdc.com>,
        Alan Kao <alankao@andestech.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Alexios Zavras <alexios.zavras@intel.com>,
        Anup Patel <anup@brainfault.org>, Gary Guo <gary@garyguo.net>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-riscv@lists.infradead.org,
        Mike Rapoport <rppt@linux.ibm.com>,
        Palmer Dabbelt <palmer@sifive.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: [RFC PATCH 2/2] RISC-V: Add basic support for SBI v0.2
Date:   Mon, 26 Aug 2019 16:32:56 -0700
Message-Id: <20190826233256.32383-3-atish.patra@wdc.com>
In-Reply-To: <20190826233256.32383-1-atish.patra@wdc.com>
References: <20190826233256.32383-1-atish.patra@wdc.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The SBI v0.2 introduces a base extension which is backward compatible
with v0.1. Implement all helper functions and minimum required SBI
calls from v0.2 for now. All other base extension function will be
added later as per need.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
---
 arch/riscv/include/asm/sbi.h | 68 +++++++++++++++++++++++++++++-------
 arch/riscv/kernel/Makefile   |  1 +
 arch/riscv/kernel/sbi.c      | 50 ++++++++++++++++++++++++++
 arch/riscv/kernel/setup.c    |  2 ++
 4 files changed, 108 insertions(+), 13 deletions(-)
 create mode 100644 arch/riscv/kernel/sbi.c

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 7f5ecaaaa0d7..4a4476956693 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -8,7 +8,6 @@
 
 #include <linux/types.h>
 
-
 #define SBI_EXT_LEGACY_SET_TIMER 0x0
 #define SBI_EXT_LEGACY_CONSOLE_PUTCHAR 0x1
 #define SBI_EXT_LEGACY_CONSOLE_GETCHAR 0x2
@@ -19,28 +18,61 @@
 #define SBI_EXT_LEGACY_REMOTE_SFENCE_VMA_ASID 0x7
 #define SBI_EXT_LEGACY_SHUTDOWN 0x8
 
-#define SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3) ({             \
+#define SBI_EXT_BASE 0x10
+
+enum sbi_ext_base_fid {
+	SBI_EXT_BASE_GET_SPEC_VERSION = 0,
+	SBI_EXT_BASE_GET_IMP_ID,
+	SBI_EXT_BASE_GET_IMP_VERSION,
+	SBI_EXT_BASE_PROBE_EXT,
+	SBI_EXT_BASE_GET_MVENDORID,
+	SBI_EXT_BASE_GET_MARCHID,
+	SBI_EXT_BASE_GET_MIMPID,
+};
+
+#define SBI_CALL_LEGACY(ext, fid, arg0, arg1, arg2, arg3) ({	\
 	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);	\
 	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);	\
 	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);	\
 	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);	\
-	register uintptr_t a7 asm ("a7") = (uintptr_t)(which);	\
+	register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);	\
+	register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);	\
 	asm volatile ("ecall"					\
-		      : "+r" (a0)				\
-		      : "r" (a1), "r" (a2), "r" (a3), "r" (a7)	\
+		      : "+r" (a0), "+r" (a1)			\
+		      : "r" (a2), "r" (a3), "r" (a6), "r" (a7) \
 		      : "memory");				\
 	a0;							\
 })
 
 /* Lazy implementations until SBI is finalized */
-#define SBI_CALL_LEGACY_0(which) SBI_CALL_LEGACY(which, 0, 0, 0, 0)
-#define SBI_CALL_LEGACY_1(which, arg0) SBI_CALL_LEGACY(which, arg0, 0, 0, 0)
-#define SBI_CALL_LEGACY_2(which, arg0, arg1) \
-		SBI_CALL_LEGACY(which, arg0, arg1, 0, 0)
-#define SBI_CALL_LEGACY_3(which, arg0, arg1, arg2) \
-		SBI_CALL_LEGACY(which, arg0, arg1, arg2, 0)
-#define SBI_CALL_LEGACY_4(which, arg0, arg1, arg2, arg3) \
-		SBI_CALL_LEGACY(which, arg0, arg1, arg2, arg3)
+#define SBI_CALL_LEGACY_0(ext) SBI_CALL_LEGACY(ext, 0, 0, 0, 0, 0)
+#define SBI_CALL_LEGACY_1(ext, arg0) SBI_CALL_LEGACY(ext, 0, arg0, 0, 0, 0)
+#define SBI_CALL_LEGACY_2(ext, arg0, arg1) \
+		SBI_CALL_LEGACY(ext, 0, arg0, arg1, 0, 0)
+#define SBI_CALL_LEGACY_3(ext, arg0, arg1, arg2) \
+		SBI_CALL_LEGACY(ext, 0, arg0, arg1, arg2, 0)
+#define SBI_CALL_LEGACY_4(ext, arg0, arg1, arg2, arg3) \
+		SBI_CALL_LEGACY(ext, 0, arg0, arg1, arg2, arg3)
+
+extern unsigned long sbi_firmware_version;
+struct sbiret {
+	long error;
+	long value;
+};
+
+void riscv_sbi_init(void);
+struct sbiret riscv_sbi_ecall(int ext, int fid, int arg0, int arg1,
+			       int arg2, int arg3);
+
+#define SBI_CALL_0(ext, fid) riscv_sbi_ecall(ext, fid, 0, 0, 0, 0)
+#define SBI_CALL_1(ext, fid, arg0) riscv_sbi_ecall(ext, fid, arg0, 0, 0, 0)
+#define SBI_CALL_2(ext, fid, arg0, arg1) \
+		riscv_sbi_ecall(ext, fid, arg0, arg1, 0, 0)
+#define SBI_CALL_3(ext, fid, arg0, arg1, arg2) \
+		riscv_sbi_ecall(ext, fid, arg0, arg1, arg2, 0)
+#define SBI_CALL_4(ext, fid, arg0, arg1, arg2, arg3) \
+		riscv_sbi_ecall(ext, fid, arg0, arg1, arg2, arg3)
+
 
 static inline void sbi_console_putchar(int ch)
 {
@@ -99,4 +131,14 @@ static inline void sbi_remote_sfence_vma_asid(const unsigned long *hart_mask,
 			  start, size, asid);
 }
 
+static inline unsigned long riscv_sbi_major_version(void)
+{
+	return (sbi_firmware_version >> 24) & 0x7f;
+}
+
+static inline unsigned long riscv_sbi_minor_version(void)
+{
+	return sbi_firmware_version & 0xffffff;
+}
+
 #endif
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 2420d37d96de..faf862d26924 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -17,6 +17,7 @@ obj-y	+= irq.o
 obj-y	+= process.o
 obj-y	+= ptrace.o
 obj-y	+= reset.o
+obj-y	+= sbi.o
 obj-y	+= setup.o
 obj-y	+= signal.o
 obj-y	+= syscall_table.o
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
new file mode 100644
index 000000000000..457b8cc0e9d9
--- /dev/null
+++ b/arch/riscv/kernel/sbi.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SBI initialilization and base extension implementation.
+ *
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ */
+
+#include <asm/sbi.h>
+#include <linux/sched.h>
+
+unsigned long sbi_firmware_version;
+
+struct sbiret riscv_sbi_ecall(int ext, int fid, int arg0, int arg1,
+			     int arg2, int arg3)
+{
+	struct sbiret ret;
+
+	register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
+	register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
+	register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
+	register uintptr_t a3 asm ("a3") = (uintptr_t)(arg3);
+	register uintptr_t a6 asm ("a6") = (uintptr_t)(fid);
+	register uintptr_t a7 asm ("a7") = (uintptr_t)(ext);
+	asm volatile ("ecall"
+		      : "+r" (a0), "+r" (a1)
+		      : "r" (a2), "r" (a3), "r" (a6), "r" (a7)
+		      : "memory");
+	ret.error = a0;
+	ret.value = a1;
+
+	return ret;
+}
+
+static struct sbiret sbi_get_spec_version(void)
+{
+	return SBI_CALL_0(SBI_EXT_BASE, SBI_EXT_BASE_GET_SPEC_VERSION);
+}
+
+void riscv_sbi_init(void)
+{
+	struct sbiret ret;
+
+	/* legacy SBI version*/
+	sbi_firmware_version = 0x1;
+	ret = sbi_get_spec_version();
+	if (!ret.error)
+		sbi_firmware_version = ret.value;
+	pr_info("SBI version implemented in firmware [%lu:%lu]\n",
+		riscv_sbi_major_version(), riscv_sbi_minor_version());
+}
diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index a990a6cb184f..4c324fd398c8 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -21,6 +21,7 @@
 #include <asm/sections.h>
 #include <asm/pgtable.h>
 #include <asm/smp.h>
+#include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/thread_info.h>
 
@@ -70,6 +71,7 @@ void __init setup_arch(char **cmdline_p)
 	swiotlb_init(1);
 #endif
 
+	riscv_sbi_init();
 #ifdef CONFIG_SMP
 	setup_smp();
 #endif
-- 
2.21.0