target/arm_adi_v5: add command "dpreg"

For very low level debug or development around DAP, it is useful
to have direct access to DP registers.

Add command "dpreg" by mimic the syntax of the existing "apreg"
command:
	$dap_name dpreg reg [value]

Change-Id: Ic4ab451eb5e74453133adee61050b4c6f656ffa3
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4612
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>

diff --git a/doc/openocd.texi b/doc/openocd.texi
index 16aa26bf546179606adccefb215f805885ec311f..def0c9d6c5f31b84119c9800d3f58ea198280364 100644 (file)
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -4087,6 +4087,18 @@ or set a new value @var{value}.
 Select AP @var{num}, defaulting to 0.
 @end deffn
 
+@deffn Command {$dap_name dpreg} reg [value]
+Displays the content of DP register at address @var{reg}, or set it to a new
+value @var{value}.
+
+In case of SWD, @var{reg} is a value in packed format
+@math{dpbanksel << 4 | addr} and assumes values 0, 4, 8 ... 0xfc.
+In case of JTAG it only assumes values 0, 4, 8 and 0xc.
+
+@emph{Note:} Consider using @command{poll off} to avoid any disturbing
+background activity by OpenOCD while you are operating at such low-level.
+@end deffn
+
 @deffn Command {$dap_name baseaddr} [num]
 Displays debug base address from MEM-AP @var{num},
 defaulting to the currently selected AP.

diff --git a/src/target/arm_adi_v5.c b/src/target/arm_adi_v5.c
index 4dc2594cf52169b28489d16a9f0b99eeec63c77a..dc5c803936ddb7238fb734f2f64b7135338978e4 100644 (file)
--- a/src/target/arm_adi_v5.c
+++ b/src/target/arm_adi_v5.c
@@ -1772,6 +1772,37 @@ COMMAND_HANDLER(dap_apreg_command)
        return retval;
 }
 
+COMMAND_HANDLER(dap_dpreg_command)
+{
+       struct adiv5_dap *dap = adiv5_get_dap(CMD_DATA);
+       uint32_t reg, value;
+       int retval;
+
+       if (CMD_ARGC < 1 || CMD_ARGC > 2)
+               return ERROR_COMMAND_SYNTAX_ERROR;
+
+       COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], reg);
+       if (reg >= 256 || (reg & 3))
+               return ERROR_COMMAND_SYNTAX_ERROR;
+
+       if (CMD_ARGC == 2) {
+               COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], value);
+               retval = dap_queue_dp_write(dap, reg, value);
+       } else {
+               retval = dap_queue_dp_read(dap, reg, &value);
+       }
+       if (retval == ERROR_OK)
+               retval = dap_run(dap);
+
+       if (retval != ERROR_OK)
+               return retval;
+
+       if (CMD_ARGC == 1)
+               command_print(CMD_CTX, "0x%08" PRIx32, value);
+
+       return retval;
+}
+
 COMMAND_HANDLER(dap_ti_be_32_quirks_command)
 {
        struct adiv5_dap *dap = adiv5_get_dap(CMD_DATA);
@@ -1836,6 +1867,14 @@ const struct command_registration dap_instance_commands[] = {
                        "(reg is byte address of a word register, like 0 4 8...)",
                .usage = "ap_num reg [value]",
        },
+       {
+               .name = "dpreg",
+               .handler = dap_dpreg_command,
+               .mode = COMMAND_EXEC,
+               .help = "read/write a register from DP "
+                       "(reg is byte address (bank << 4 | reg) of a word register, like 0 4 8...)",
+               .usage = "reg [value]",
+       },
        {
                .name = "baseaddr",
                .handler = dap_baseaddr_command,