Adds read-only register masks for the DwC I3C controller.

Signed-off-by: Joe Komlodi <komlodi@google.com>
Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Patrick Venture <venture@google.com>
Reviewed-by: Jamin Lin <jamin_lin@aspeedtech.com>
---
 hw/i3c/dw-i3c.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/hw/i3c/dw-i3c.c b/hw/i3c/dw-i3c.c
index 7bb33c7a9e..02fa9b3c00 100644
--- a/hw/i3c/dw-i3c.c
+++ b/hw/i3c/dw-i3c.c
@@ -296,6 +296,45 @@ static const uint32_t dw_i3c_resets[DW_I3C_NR_REGS] = {
     [R_SLAVE_CONFIG]                = 0x00000023,
 };
 
+static const uint32_t dw_i3c_ro[DW_I3C_NR_REGS] = {
+    [R_DEVICE_CTRL]                 = 0x04fffe00,
+    [R_DEVICE_ADDR]                 = 0x7f807f80,
+    [R_HW_CAPABILITY]               = 0xffffffff,
+    [R_IBI_QUEUE_STATUS]            = 0xffffffff,
+    [R_DATA_BUFFER_THLD_CTRL]       = 0xf8f8f8f8,
+    [R_IBI_QUEUE_CTRL]              = 0xfffffff0,
+    [R_RESET_CTRL]                  = 0xffffffc0,
+    [R_SLV_EVENT_CTRL]              = 0xffffff3f,
+    [R_INTR_STATUS]                 = 0xffff809f,
+    [R_INTR_STATUS_EN]              = 0xffff8080,
+    [R_INTR_SIGNAL_EN]              = 0xffff8080,
+    [R_INTR_FORCE]                  = 0xffff8000,
+    [R_QUEUE_STATUS_LEVEL]          = 0xffffffff,
+    [R_DATA_BUFFER_STATUS_LEVEL]    = 0xffffffff,
+    [R_PRESENT_STATE]               = 0xffffffff,
+    [R_CCC_DEVICE_STATUS]           = 0xffffffff,
+    [R_I3C_VER_ID]                  = 0xffffffff,
+    [R_I3C_VER_TYPE]                = 0xffffffff,
+    [R_DEVICE_ADDR_TABLE_POINTER]   = 0xffffffff,
+    [R_DEV_CHAR_TABLE_POINTER]      = 0xffcbffff,
+    [R_SLV_PID_VALUE]               = 0xffff0fff,
+    [R_SLV_CHAR_CTRL]               = 0xffffffff,
+    [A_VENDOR_SPECIFIC_REG_POINTER] = 0xffffffff,
+    [R_SLV_MAX_LEN]                 = 0xffffffff,
+    [R_MAX_READ_TURNAROUND]         = 0xffffffff,
+    [R_MAX_DATA_SPEED]              = 0xffffffff,
+    [R_SLV_INTR_REQ]                = 0xfffffff0,
+    [R_SLV_TSX_SYMBL_TIMING]        = 0xffffffc0,
+    [R_DEVICE_CTRL_EXTENDED]        = 0xfffffff8,
+    [R_SCL_I3C_OD_TIMING]           = 0xff00ff00,
+    [R_SCL_I3C_PP_TIMING]           = 0xff00ff00,
+    [R_SCL_I2C_FMP_TIMING]          = 0xff000000,
+    [R_SCL_EXT_TERMN_LCNT_TIMING]   = 0x0000fff0,
+    [R_BUS_IDLE_TIMING]             = 0xfff00000,
+    [R_EXTENDED_CAPABILITY]         = 0xffffffff,
+    [R_SLAVE_CONFIG]                = 0xffffffff,
+};
+
 static uint64_t dw_i3c_read(void *opaque, hwaddr offset, unsigned size)
 {
     DWI3C *s = DW_I3C(opaque);
@@ -324,6 +363,7 @@ static void dw_i3c_write(void *opaque, hwaddr offset, uint64_t value,
 
     trace_dw_i3c_write(s->id, offset, value);
 
+    value &= ~dw_i3c_ro[addr];
     switch (addr) {
     case R_HW_CAPABILITY:
     case R_RESPONSE_QUEUE_PORT:
-- 
2.43.0