[M] Change in coreboot[main]: arch/riscv: add new SBI calls

[ron minnich (Code Review)]

ron minnich has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/81294?usp=email )

Change subject: arch/riscv: add new SBI calls
......................................................................

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

clang-formatted-by: Ronald G Minnich

Change-Id: I5dac8613020e26ec74ac1c74158fc9791553693f
---
M src/arch/riscv/sbi.c
1 file changed, 80 insertions(+), 5 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/94/81294/1

diff --git a/src/arch/riscv/sbi.c b/src/arch/riscv/sbi.c
index 8bf21b7..fd6d1d3 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 +50,52 @@
    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_EXTENSION_ID:
+		printk(BIOS_EMERG, "SBI_EXTENSION_ID\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 in the case of an older SoC like the FU[57]40
+ * 1 is the most basic SBI, per the standard; per the standard,
+ * all the other values can be 0.
+ */
+int __weak sbi_features[] = {1, 0, 0, 0, 0, 0, 0};
+
 /*
  * sbi is triggered by the s-mode ecall
  * parameter : register a0 a1 a2
@@ -58,11 +105,24 @@
 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) {
+	/*
+	 * These are for when things are going seriously wrong.
+	 * In practice we don't want them compiled in,
+	 * hence the if(0).
+	 */
+	if (0) {
+		printk(BIOS_EMERG, "%s\n", __func__);
+		print_sbi_trap(eid);
+	}
+
+	switch (eid) {
    case SBI_SET_TIMER:
 #if __riscv_xlen == 32
    	ret = sbi_set_timer(arg0 + ((uint64_t)arg1 << 32));
@@ -96,10 +156,25 @@
    case SBI_SHUTDOWN:
    	ret = send_ipi((uintptr_t *)arg0, IPI_SHUTDOWN);
    	break;
+	case SBI_EXTENSION_ID:
+		/* 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;
+		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;
+
+	if (0)
+		printk(BIOS_EMERG, "%s:returning [%lx,%lx] to %lx\n", __func__, sbiret, ret, retpc);
+
+	write_csr(mepc, retpc);
 }