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RISC-V: Add SBI debug console helper routines

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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 <apatel@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20231124070905.1043092-3-apatel@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Anup Patel 2023-11-24 12:39:02 +05:30 committed by Palmer Dabbelt
parent f503b167b6
commit f43fabf444
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
2 changed files with 71 additions and 0 deletions
arch/riscv
include/asm
sbi.h
kernel
sbi.c

5
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(const char *bytes, unsigned int num_bytes);
int sbi_debug_console_read(char *bytes, unsigned int num_bytes);
#else /* CONFIG_RISCV_SBI */
static inline int sbi_remote_fence_i(const struct cpumask *cpu_mask) { return -1; }
static inline void sbi_init(void) {}

66
arch/riscv/kernel/sbi.c

@ -7,6 +7,7 @@
#include <linux/bits.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/pm.h>
#include <linux/reboot.h>
#include <asm/sbi.h>
@ -571,6 +572,66 @@ long sbi_get_mimpid(void)
}
EXPORT_SYMBOL_GPL(sbi_get_mimpid);
bool sbi_debug_console_available;
int sbi_debug_console_write(const char *bytes, unsigned int num_bytes)
{
phys_addr_t base_addr;
struct sbiret ret;
if (!sbi_debug_console_available)
return -EOPNOTSUPP;
if (is_vmalloc_addr(bytes))
base_addr = page_to_phys(vmalloc_to_page(bytes)) +
offset_in_page(bytes);
else
base_addr = __pa(bytes);
if (PAGE_SIZE < (offset_in_page(bytes) + num_bytes))
num_bytes = PAGE_SIZE - offset_in_page(bytes);
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);
if (ret.error == SBI_ERR_FAILURE)
return -EIO;
return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value;
}
int sbi_debug_console_read(char *bytes, unsigned int num_bytes)
{
phys_addr_t base_addr;
struct sbiret ret;
if (!sbi_debug_console_available)
return -EOPNOTSUPP;
if (is_vmalloc_addr(bytes))
base_addr = page_to_phys(vmalloc_to_page(bytes)) +
offset_in_page(bytes);
else
base_addr = __pa(bytes);
if (PAGE_SIZE < (offset_in_page(bytes) + num_bytes))
num_bytes = PAGE_SIZE - offset_in_page(bytes);
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);
if (ret.error == SBI_ERR_FAILURE)
return -EIO;
return ret.error ? sbi_err_map_linux_errno(ret.error) : ret.value;
}
void __init sbi_init(void)
{
int ret;
@ -612,6 +673,11 @@ void __init sbi_init(void)
sbi_srst_reboot_nb.priority = 192;
register_restart_handler(&sbi_srst_reboot_nb);
}
if ((sbi_spec_version >= sbi_mk_version(2, 0)) &&
(sbi_probe_extension(SBI_EXT_DBCN) > 0)) {
pr_info("SBI DBCN extension detected\n");
sbi_debug_console_available = true;
}
} else {
__sbi_set_timer = __sbi_set_timer_v01;
__sbi_send_ipi = __sbi_send_ipi_v01;