On Wed, Nov 22, 2023 at 4:15 AM Samuel Holland
[off-list ref] wrote:

Hi Anup,

On 2023-11-17 9:38 PM, Anup Patel wrote:

quoted

Let us provide SBI debug console helper routines which can be
shared by serial/earlycon-riscv-sbi.c and hvc/hvc_riscv_sbi.c.

Signed-off-by: Anup Patel <redacted>
---
 arch/riscv/include/asm/sbi.h |  5 +++++
 arch/riscv/kernel/sbi.c      | 43 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 66f3933c14f6..ee7aef5f6233 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h

@@ -334,6 +334,11 @@ static inline unsigned long sbi_mk_version(unsigned long major,
 }

 int sbi_err_map_linux_errno(int err);
+
+extern bool sbi_debug_console_available;
+int sbi_debug_console_write(unsigned int num_bytes, phys_addr_t base_addr);
+int sbi_debug_console_read(unsigned int num_bytes, phys_addr_t base_addr);
+
 #else /* CONFIG_RISCV_SBI */
 static inline int sbi_remote_fence_i(const struct cpumask *cpu_mask) { return -1; }
 static inline void sbi_init(void) {}

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 5a62ed1da453..73a9c22c3945 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c

@@ -571,6 +571,44 @@ long sbi_get_mimpid(void)
 }
 EXPORT_SYMBOL_GPL(sbi_get_mimpid);

+bool sbi_debug_console_available;
+
+int sbi_debug_console_write(unsigned int num_bytes, phys_addr_t base_addr)
+{
+     struct sbiret ret;
+
+     if (!sbi_debug_console_available)
+             return -EOPNOTSUPP;
+
+     if (IS_ENABLED(CONFIG_32BIT))
+             ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+                             num_bytes, lower_32_bits(base_addr),
+                             upper_32_bits(base_addr), 0, 0, 0);
+     else
+             ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_WRITE,
+                             num_bytes, base_addr, 0, 0, 0, 0);
+
+     return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value;
+}
+
+int sbi_debug_console_read(unsigned int num_bytes, phys_addr_t base_addr)
+{
+     struct sbiret ret;
+
+     if (!sbi_debug_console_available)
+             return -EOPNOTSUPP;
+
+     if (IS_ENABLED(CONFIG_32BIT))
+             ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ,
+                             num_bytes, lower_32_bits(base_addr),
+                             upper_32_bits(base_addr), 0, 0, 0);
+     else
+             ret = sbi_ecall(SBI_EXT_DBCN, SBI_EXT_DBCN_CONSOLE_READ,
+                             num_bytes, base_addr, 0, 0, 0, 0);
+
+     return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value;
+}

Since every place that calls these functions will need to do the vmalloc lookup,
would it make sense to do it here, and have these take a pointer instead?

Yes, that's better. I will update.

Regards,
Anup