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Diffstat (limited to 'arch/riscv/kernel/sbi.c')
-rw-r--r--arch/riscv/kernel/sbi.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 5a62ed1da4..e66e0999a8 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/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;