arch/riscv: add new SBI calls

This is just a start. We are playing catch up.

7 down, 70+ to go.

Signed-off-by: Ronald G Minnich <rminnich@gmail.com>

Change-Id: I5dac8613020e26ec74ac1c74158fc9791553693f
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81294
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin L Roth <gaumless@gmail.com>

1 files changed, 70 insertions, 5 deletions

diff --git a/src/arch/riscv/sbi.c b/src/arch/riscv/sbi.c
index 8bf21b72ba..2ef7625f57 100644
--- a/src/arch/riscv/sbi.c
+++ b/src/arch/riscv/sbi.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <console/console.h>
 #include <mcall.h>
 #include <stdint.h>
 #include <arch/exception.h>
@@ -49,6 +50,54 @@ static uintptr_t sbi_clear_ipi(void)
 	return 0;
 }
 
+static void print_sbi_trap(uintptr_t trap)
+{
+	switch (trap) {
+	case SBI_SHUTDOWN:
+		printk(BIOS_EMERG, "SBI_SHUTDOWN\n");
+		break;
+	case SBI_REMOTE_SFENCE_VMA_ASID:
+		printk(BIOS_EMERG, "SBI_REMOTE_SFENCE_VMA_ASID\n");
+		break;
+	case SBI_REMOTE_SFENCE_VMA:
+		printk(BIOS_EMERG, "SBI_REMOTE_SFENCE_VMA\n");
+		break;
+	case SBI_REMOTE_FENCE_I:
+		printk(BIOS_EMERG, "SBI_REMOTE_FENCE_I\n");
+		break;
+	case SBI_SEND_IPI:
+		printk(BIOS_EMERG, "SBI_SEND_IPI\n");
+		break;
+	case SBI_CLEAR_IPI:
+		printk(BIOS_EMERG, "SBI_CLEAR_IPI\n");
+		break;
+	case SBI_CONSOLE_GETCHAR:
+		printk(BIOS_EMERG, "SBI_CONSOLE_GETCHAR\n");
+		break;
+	case SBI_CONSOLE_PUTCHAR:
+		printk(BIOS_EMERG, "SBI_CONSOLE_PUTCHAR\n");
+		break;
+	case SBI_SET_TIMER:
+		printk(BIOS_EMERG, "SBI_SET_TIMER\n");
+		break;
+	case SBI_BASE_EXTENSION:
+		printk(BIOS_EMERG, "SBI_BASE_EXTENSION\n");
+		break;
+	default:
+		printk(BIOS_EMERG, "%lx is an unknown SBI trap\n", trap);
+		break;
+	}
+}
+
+/*
+ * These are the default SBI extension values.
+ * They can be overridden, by specialized code,
+ * but since this is a GPL SBI, it may be better
+ * that they evolve as we extend this SBI.
+ * over time, the will be updated.
+ */
+int sbi_features[] = {1, 0, 0, 0, 0, 0, 0};
+
 /*
  * sbi is triggered by the s-mode ecall
  * parameter : register a0 a1 a2
@@ -58,11 +107,14 @@ static uintptr_t sbi_clear_ipi(void)
 void handle_sbi(struct trapframe *tf)
 {
 	uintptr_t ret = 0;
+	uintptr_t sbiret = 0;
 	uintptr_t arg0 = tf->gpr[10];
 	__maybe_unused uintptr_t arg1 = tf->gpr[11];
-	uintptr_t which = tf->gpr[17];
+	uintptr_t fid = tf->gpr[16];
+	uintptr_t eid = tf->gpr[17];
+	uintptr_t retpc = read_csr(mepc) + 4;
 
-	switch (which) {
+	switch (eid) {
 	case SBI_SET_TIMER:
 #if __riscv_xlen == 32
 		ret = sbi_set_timer(arg0 + ((uint64_t)arg1 << 32));
@@ -96,10 +148,23 @@ void handle_sbi(struct trapframe *tf)
 	case SBI_SHUTDOWN:
 		ret = send_ipi((uintptr_t *)arg0, IPI_SHUTDOWN);
 		break;
+	case SBI_BASE_EXTENSION:
+		/* zero is an allowed return value for most features,
+		 * and the only required one is feature 0.
+		 * So this test will return legal values
+		 * for all possible values of fid.
+		 */
+		if (fid < ARRAY_SIZE(sbi_features))
+			ret = sbi_features[fid];
+		break;
 	default:
-		ret = -SBI_ENOSYS;
+		print_sbi_trap(eid);
+		printk(BIOS_EMERG, "SBI: %lx: ENOSYS\n", fid);
+		sbiret = -SBI_ENOSYS;
 		break;
 	}
-	tf->gpr[10] = ret;
-	write_csr(mepc, read_csr(mepc) + 4);
+	tf->gpr[10] = sbiret;
+	tf->gpr[11] = ret;
+
+	write_csr(mepc, retpc);
 }