Default console of riscvemu is available Virt I/O console and as a HTIF
blocking character device. We already support Virt I/O console, but the
HTIF is easier to support for very early low level debugging. Add
DEBUG_LL support to facilitate using it.
Note: when using a framebuffer, riscvemu doesn't allocate a default
console, so barebox calling into HTIF will segfault the emulator.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
arch/riscv/include/asm/debug_ll.h | 11 +++++++++++
arch/riscv/include/asm/htif.h | 9 +++++++++
common/Kconfig | 9 +++++++++
3 files changed, 29 insertions(+)
diff --git a/arch/riscv/include/asm/debug_ll.h b/arch/riscv/include/asm/debug_ll.h
index 867c96d79724..de9bc5f5fd33 100644
--- a/arch/riscv/include/asm/debug_ll.h
+++ b/arch/riscv/include/asm/debug_ll.h
@@ -53,6 +53,17 @@ static inline void PUTC_LL(char ch)
#include <asm/debug_ll_litex.h>
+#elif defined CONFIG_DEBUG_RISCVEMU_HTIF
+
+#include <asm/htif.h>
+
+#ifndef __ASSEMBLY__
+static inline void PUTC_LL(char ch)
+{
+ htif_putc(IOMEM(HTIF_DEFAULT_BASE_ADDR), ch);
+}
+#endif
+
#endif
#ifndef debug_ll_init
diff --git a/arch/riscv/include/asm/htif.h b/arch/riscv/include/asm/htif.h
index 7312f09d2e6e..b35afdd98e1d 100644
--- a/arch/riscv/include/asm/htif.h
+++ b/arch/riscv/include/asm/htif.h
@@ -11,6 +11,10 @@
#define HTIF_DEV_SYSCALL 0
#define HTIF_CMD_SYSCALL 0
+#define HTIF_DEV_CONSOLE 1 /* blocking character device */
+#define HTIF_CMD_GETCHAR 0
+#define HTIF_CMD_PUTCHAR 1
+
#ifndef __ASSEMBLY__
#include <linux/types.h>
@@ -26,6 +30,11 @@ static inline void htif_tohost(u8 device, u8 command, u64 arg)
__htif_tohost(IOMEM(HTIF_DEFAULT_BASE_ADDR), device, command, arg);
}
+static inline void htif_putc(void __iomem *base, int c)
+{
+ __htif_tohost(base, HTIF_DEV_CONSOLE, HTIF_CMD_PUTCHAR, c);
+}
+
#endif
#endif
diff --git a/common/Kconfig b/common/Kconfig
index 802bd9bfbb2e..2f014509da0d 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -1403,6 +1403,15 @@ config DEBUG_RISCV_VIRT
depends on SOC_VIRT
select DEBUG_LL_NS16550
+config DEBUG_RISCVEMU_HTIF
+ bool "riscvemu HTIF port"
+ depends on SOC_VIRT
+ help
+ When run without graphics support, tinyemu will expose access
+ to the Virt I/O console as HTIF blocking console device as well.
+ This is useful for low level debugging before Virt I/O DMA is
+ initialized.
+
config DEBUG_SIFIVE
bool "SiFive serial0 port"
depends on SOC_SIFIVE
--
2.30.2
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