lib: Implement Hart State Management (HSM) SBI extension

This patch adds support HSM extension. The specification is available
at https://github.com/riscv/riscv-sbi-doc.

It allows to implement hart hotplug and fixed ordered hart booting in
supervisor.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

5 files changed, 62 insertions, 0 deletions

diff --git a/include/sbi/sbi_ecall.h b/include/sbi/sbi_ecall.h
index 2a3500f..1b56496 100644
--- a/include/sbi/sbi_ecall.h
+++ b/include/sbi/sbi_ecall.h
@@ -39,6 +39,7 @@ extern struct sbi_ecall_extension ecall_time;
 extern struct sbi_ecall_extension ecall_rfence;
 extern struct sbi_ecall_extension ecall_ipi;
 extern struct sbi_ecall_extension ecall_vendor;
+extern struct sbi_ecall_extension ecall_hsm;
 
 u16 sbi_ecall_version_major(void);
 
diff --git a/include/sbi/sbi_ecall_interface.h b/include/sbi/sbi_ecall_interface.h
index ba88e8b..727a545 100644
--- a/include/sbi/sbi_ecall_interface.h
+++ b/include/sbi/sbi_ecall_interface.h
@@ -26,6 +26,7 @@
 #define SBI_EXT_TIME				0x54494D45
 #define SBI_EXT_IPI				0x735049
 #define SBI_EXT_RFENCE				0x52464E43
+#define SBI_EXT_HSM				0x48534D
 
 /* SBI function IDs for BASE extension*/
 #define SBI_EXT_BASE_GET_SPEC_VERSION		0x0
@@ -51,6 +52,11 @@
 #define SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA	0x5
 #define SBI_EXT_RFENCE_REMOTE_HFENCE_VVMA_ASID	0x6
 
+/* SBI function IDs for HSM extension */
+#define SBI_EXT_HSM_HART_START			0x0
+#define SBI_EXT_HSM_HART_STOP			0x1
+#define SBI_EXT_HSM_HART_GET_STATUS		0x2
+
 #define SBI_HSM_HART_STATUS_STARTED		0x0
 #define SBI_HSM_HART_STATUS_STOPPED		0x1
 #define SBI_HSM_HART_STATUS_START_PENDING	0x2
diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
index dc52a9f..39e9295 100644
--- a/lib/sbi/objects.mk
+++ b/lib/sbi/objects.mk
@@ -18,6 +18,7 @@ libsbi-objs-y += sbi_ecall_base.o
 libsbi-objs-y += sbi_ecall_legacy.o
 libsbi-objs-y += sbi_ecall_replace.o
 libsbi-objs-y += sbi_ecall_vendor.o
+libsbi-objs-y += sbi_ecall_hsm.o
 libsbi-objs-y += sbi_emulate_csr.o
 libsbi-objs-y += sbi_fifo.o
 libsbi-objs-y += sbi_hfence.o
diff --git a/lib/sbi/sbi_ecall.c b/lib/sbi/sbi_ecall.c
index 82397c4..2383e4f 100644
--- a/lib/sbi/sbi_ecall.c
+++ b/lib/sbi/sbi_ecall.c
@@ -138,6 +138,9 @@ int sbi_ecall_init(void)
 	ret = sbi_ecall_register_extension(&ecall_base);
 	if (ret)
 		return ret;
+	ret = sbi_ecall_register_extension(&ecall_hsm);
+	if (ret)
+		return ret;
 	ret = sbi_ecall_register_extension(&ecall_legacy);
 	if (ret)
 		return ret;
diff --git a/lib/sbi/sbi_ecall_hsm.c b/lib/sbi/sbi_ecall_hsm.c
new file mode 100644
index 0000000..528bc80
--- /dev/null
+++ b/lib/sbi/sbi_ecall_hsm.c
@@ -0,0 +1,51 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2020 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *   Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <sbi/sbi_ecall.h>
+#include <sbi/sbi_ecall_interface.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_version.h>
+#include <sbi/sbi_hsm.h>
+#include <sbi/riscv_asm.h>
+
+static int sbi_ecall_hsm_handler(struct sbi_scratch *scratch,
+				 unsigned long extid, unsigned long funcid,
+				 unsigned long *args, unsigned long *out_val,
+				 struct sbi_trap_info *out_trap)
+{
+	int ret = 0;
+	int hstate;
+
+	switch (funcid) {
+	case SBI_EXT_HSM_HART_START:
+		ret = sbi_hsm_hart_start(scratch, args[0], args[1], args[2]);
+		break;
+	case SBI_EXT_HSM_HART_STOP:
+		ret = sbi_hsm_hart_stop(scratch, TRUE);
+		break;
+	case SBI_EXT_HSM_HART_GET_STATUS:
+		hstate = sbi_hsm_hart_get_state(scratch, args[0]);
+		ret = sbi_hsm_hart_state_to_status(hstate);
+		break;
+	default:
+		ret = SBI_ENOTSUPP;
+	};
+	if (ret >= 0) {
+		*out_val = ret;
+		ret = 0;
+	}
+
+	return ret;
+}
+
+struct sbi_ecall_extension ecall_hsm = {
+	.extid_start = SBI_EXT_HSM,
+	.extid_end = SBI_EXT_HSM,
+	.handle = sbi_ecall_hsm_handler,
+};