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Enable timer from supervisor

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This commit is contained in:
Rodrigo Arias Mallo 2024-08-21 12:28:17 +02:00
parent 2c5f8a8ccf
commit 7091ca455c
2 changed files with 12 additions and 10 deletions
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2
JOURNAL.md
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@ -3463,7 +3463,7 @@ Let's set the stvec to zero, so it causes a machine exception.
# 2024-08-21
I tried with the new bitstream (ox_u55c_46619ef4.bit) setting the stvec to zero
I tried with the new bitstream (`ox_u55c_46619ef4.bit`) setting the stvec to zero
and I can see the OpenSBI handler stopping, probably due to the jump to zero
address:

20
opensbi-test-plic.patch
View File

@ -1,5 +1,5 @@
diff --git a/lib/sbi/sbi_irqchip.c b/lib/sbi/sbi_irqchip.c
index 0ae604a..54449c7 100644
index 0ae604a..c446e60 100644
--- a/lib/sbi/sbi_irqchip.c
+++ b/lib/sbi/sbi_irqchip.c
@@ -9,6 +9,9 @@
@ -25,7 +25,7 @@ index 0ae604a..54449c7 100644
return 0;
}
@@ -47,8 +52,161 @@ void sbi_irqchip_exit(struct sbi_scratch *scratch)
@@ -47,8 +52,163 @@ void sbi_irqchip_exit(struct sbi_scratch *scratch)
{
const struct sbi_platform *plat = sbi_platform_ptr(scratch);
@ -61,6 +61,10 @@ index 0ae604a..54449c7 100644
+#define MSTATUS_MPP_MASK (3 << 11)
+#define MSTATUS_MPP_SUPERVISOR (1 << 11)
+
+static volatile unsigned long *mtime = (unsigned long *)(AUX_TIMER_BASE + MTIME_OFFSET);
+static volatile unsigned long *mtimecmp = (unsigned long *)(AUX_TIMER_BASE + MTIMECMP_OFFSET);
+
+
+static void dumpregs(int machine)
+{
+ char *prefix = "\t";
@ -108,6 +112,11 @@ index 0ae604a..54449c7 100644
+{
+ sbi_printf("Hello from supervisor\n");
+ dumpregs(0);
+
+ /* Enable timer interrupt */
+ *mtimecmp = *mtime + 10000;
+
+ sbi_printf("Timer alarm programmed\n");
+ sbi_printf("Waiting for interrupt...\n");
+ int i = 0;
+ char *s = "-\\|/";
@ -129,9 +138,6 @@ index 0ae604a..54449c7 100644
+{
+ sbi_printf("--- TESTING PLIC ---\n");
+
+ volatile unsigned long *mtime = (unsigned long *)(AUX_TIMER_BASE + MTIME_OFFSET);
+ volatile unsigned long *mtimecmp = (unsigned long *)(AUX_TIMER_BASE + MTIMECMP_OFFSET);
+
+ /* Disable auxiliar timer interrupt */
+ *mtimecmp = 0xffffffffUL;
+ sbi_printf("Timer interrupt disabled\n");
@ -174,10 +180,6 @@ index 0ae604a..54449c7 100644
+ //sbi_printf("Enabling MIE in MSTATUS register\n");
+ //csr_set(CSR_MSTATUS, MSTATUS_MIE); /* Needed? */
+
+ /* Enable timer interrupt */
+ *mtimecmp = *mtime + 10000;
+
+ sbi_printf("Timer alarm programmed\n");
+ sbi_printf("Switching to supervisor\n");
+
+ dumpregs(1);