Unverified Commit f43fabf4 authored by Anup Patel's avatar Anup Patel Committed by Palmer Dabbelt
Browse files

RISC-V: Add SBI debug console helper routines 



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: default avatarAnup Patel <apatel@ventanamicro.com>
Reviewed-by: default avatarAndrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20231124070905.1043092-3-apatel@ventanamicro.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent f503b167

arch/riscv/include/asm/sbi.h

+5 −0
Original line number Diff line number Diff line
@@ -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) {}

arch/riscv/kernel/sbi.c

+66 −0
Original line number Diff line number Diff line
@@ -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;