tty: Add SBI debug console support to HVC SBI driver

RISC-V SBI specification supports advanced debug console
support via SBI DBCN extension.

Extend the HVC SBI driver to support it.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20231124070905.1043092-5-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index 4f9264d005c06d55e5853bf9b12e329907648ca3..6e05c5c7bca1ad258502eaf158b94534c1cdd23d 100644 (file)
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -108,7 +108,7 @@ config HVC_DCC_SERIALIZE_SMP
 
 config HVC_RISCV_SBI
        bool "RISC-V SBI console support"
-       depends on RISCV_SBI_V01
+       depends on RISCV_SBI
        select HVC_DRIVER
        help
          This enables support for console output via RISC-V SBI calls, which

diff --git a/drivers/tty/hvc/hvc_riscv_sbi.c b/drivers/tty/hvc/hvc_riscv_sbi.c
index 31f53fa77e4af5f1c4cd1ecd4677210d1d515cf0..2f3571f17ecd466cee0346f28c5dd53103287864 100644 (file)
--- a/drivers/tty/hvc/hvc_riscv_sbi.c
+++ b/drivers/tty/hvc/hvc_riscv_sbi.c
@@ -39,21 +39,44 @@ static int hvc_sbi_tty_get(uint32_t vtermno, char *buf, int count)
        return i;
 }
 
-static const struct hv_ops hvc_sbi_ops = {
+static const struct hv_ops hvc_sbi_v01_ops = {
        .get_chars = hvc_sbi_tty_get,
        .put_chars = hvc_sbi_tty_put,
 };
 
-static int __init hvc_sbi_init(void)
+static int hvc_sbi_dbcn_tty_put(uint32_t vtermno, const char *buf, int count)
 {
-       return PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_ops, 16));
+       return sbi_debug_console_write(buf, count);
 }
-device_initcall(hvc_sbi_init);
 
-static int __init hvc_sbi_console_init(void)
+static int hvc_sbi_dbcn_tty_get(uint32_t vtermno, char *buf, int count)
 {
-       hvc_instantiate(0, 0, &hvc_sbi_ops);
+       return sbi_debug_console_read(buf, count);
+}
+
+static const struct hv_ops hvc_sbi_dbcn_ops = {
+       .put_chars = hvc_sbi_dbcn_tty_put,
+       .get_chars = hvc_sbi_dbcn_tty_get,
+};
+
+static int __init hvc_sbi_init(void)
+{
+       int err;
+
+       if (sbi_debug_console_available) {
+               err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_dbcn_ops, 256));
+               if (err)
+                       return err;
+               hvc_instantiate(0, 0, &hvc_sbi_dbcn_ops);
+       } else if (IS_ENABLED(CONFIG_RISCV_SBI_V01)) {
+               err = PTR_ERR_OR_ZERO(hvc_alloc(0, 0, &hvc_sbi_v01_ops, 256));
+               if (err)
+                       return err;
+               hvc_instantiate(0, 0, &hvc_sbi_v01_ops);
+       } else {
+               return -ENODEV;
+       }
 
        return 0;
 }
-console_initcall(hvc_sbi_console_init);
+device_initcall(hvc_sbi_init);