riscv: Add SBI debug trigger extension and function ids

Debug trigger extension is an SBI extension to support native debugging
in S-mode and VS-mode. This patch adds the extension and the function
IDs defined by the extension.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Link: https://patch.msgid.link/20250710125231.653967-2-hchauhan@ventanamicro.com
[pjw@kernel.org: updated to apply]
Signed-off-by: Paul Walmsley <pjw@kernel.org>

Author: hschauhan

arch/riscv/include/asm/sbi.h

@@ -37,6 +37,7 @@ enum sbi_ext_id {
 	SBI_EXT_NACL = 0x4E41434C,
 	SBI_EXT_FWFT = 0x46574654,
 	SBI_EXT_MPXY = 0x4D505859,
+	SBI_EXT_DBTR = 0x44425452,
 
 	/* Experimentals extensions must lie within this range */
 	SBI_EXT_EXPERIMENTAL_START = 0x08000000,
@@ -505,6 +506,34 @@ enum sbi_mpxy_rpmi_attribute_id {
 #define SBI_MPXY_CHAN_CAP_SEND_WITHOUT_RESP	BIT(4)
 #define SBI_MPXY_CHAN_CAP_GET_NOTIFICATIONS	BIT(5)
 
+/* SBI debug triggers function IDs */
+enum sbi_ext_dbtr_fid {
+	SBI_EXT_DBTR_NUM_TRIGGERS = 0,
+	SBI_EXT_DBTR_SETUP_SHMEM,
+	SBI_EXT_DBTR_TRIG_READ,
+	SBI_EXT_DBTR_TRIG_INSTALL,
+	SBI_EXT_DBTR_TRIG_UPDATE,
+	SBI_EXT_DBTR_TRIG_UNINSTALL,
+	SBI_EXT_DBTR_TRIG_ENABLE,
+	SBI_EXT_DBTR_TRIG_DISABLE,
+};
+
+struct sbi_dbtr_data_msg {
+	unsigned long tstate;
+	unsigned long tdata1;
+	unsigned long tdata2;
+	unsigned long tdata3;
+};
+
+struct sbi_dbtr_id_msg {
+	unsigned long idx;
+};
+
+union sbi_dbtr_shmem_entry {
+	struct sbi_dbtr_data_msg data;
+	struct sbi_dbtr_id_msg id;
+};
+
 /* SBI spec version fields */
 #define SBI_SPEC_VERSION_DEFAULT	0x1
 #define SBI_SPEC_VERSION_MAJOR_SHIFT	24