[PULL 9/9] hw/i3c/dw-i3c: Fix BCR/DCR extraction and PID assembly during ENTDAA

["Cédric Le Goater" <clg@redhat.com>]

From: Ashish Anand <ashish.a6@samsung.com>

The target_info union in dw_i3c_addr_assign_cmd() declares pid, bcr,
and dcr as separate union members, causing them to all alias b[0]
rather than their correct positions in the ENTDAA response buffer.
This results in dw_i3c_update_char_table() being called with BCR and
DCR both read from b[0] instead of b[6] and b[7] respectively,
corrupting the device characteristics table on every ENTDAA operation.
Fix by replacing the broken members with uint64_t d and extracting fields
per the I3C spec ENTDAA wire format.

Additionally, dw_i3c_update_char_table() incorrectly splits PID across
LOC1 and LOC2 at bit 32. Per the Linux kernel HCI driver
(drivers/i3c/master/mipi-i3c-hci/dct_v1.c), the DCT layout requires
LOC1 to hold pid[47:16] and LOC2 to hold pid[15:0]. Fix the split
accordingly.

Signed-off-by: Ashish Anand <ashish.a6@samsung.com>
Reviewed-by: Jamin Lin <jamin_lin@aspeedtech.com>
Link: https://lore.kernel.org/qemu-devel/20260505134002.509037-1-ashish.a6@samsung.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
 include/hw/i3c/i3c.h |  7 +++++++
 hw/i3c/dw-i3c.c      | 16 +++++++---------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/include/hw/i3c/i3c.h b/include/hw/i3c/i3c.h
index 6ba90793ad01..dcf8d9b1435b 100644
--- a/include/hw/i3c/i3c.h
+++ b/include/hw/i3c/i3c.h
@@ -138,6 +138,13 @@ struct I3CTarget {
     uint8_t static_address;
     uint8_t dcr;
     uint8_t bcr;
+    /*
+     * Provisioned ID. Since core.c sends this LSB-first during ENTDAA
+     * via (pid >> (offset * 8)) & 0xff, targets must store it
+     * pre-reversed so that pid[47:40] goes on the wire first, as
+     * required by the I3C spec.
+     *  e.g. for a device with pid 0xAABBCCDDEEFF, store 0xFFEEDDCCBBAA.
+     */
     uint64_t pid;
 
     /* CCC State tracking. */
diff --git a/hw/i3c/dw-i3c.c b/hw/i3c/dw-i3c.c
index d87d42be8914..17ff484c5df1 100644
--- a/hw/i3c/dw-i3c.c
+++ b/hw/i3c/dw-i3c.c
@@ -1459,11 +1459,10 @@ static void dw_i3c_update_char_table(DWI3C *s, uint8_t offset, uint64_t pid,
                                           P_DEV_CHAR_TABLE_START_ADDR) /
                                           sizeof(uint32_t)) +
                                           (offset * sizeof(uint32_t));
-    s->regs[dev_index] = pid & 0xffffffff;
-    pid >>= 32;
+    s->regs[dev_index] = (pid >> 16) & 0xffffffff;
     s->regs[dev_index + 1] = FIELD_DP32(s->regs[dev_index + 1],
                                         DEVICE_CHARACTERISTIC_TABLE_LOC2,
-                                        MSB_PID, pid);
+                                        MSB_PID, pid & 0xffff);
     s->regs[dev_index + 2] = FIELD_DP32(s->regs[dev_index + 2],
                                         DEVICE_CHARACTERISTIC_TABLE_LOC3, DCR,
                                         dcr);
@@ -1507,10 +1506,9 @@ static void dw_i3c_addr_assign_cmd(DWI3C *s, DWI3CAddrAssignCmd cmd)
     for (i = 0; i < cmd.dev_count; i++) {
         uint8_t addr = dw_i3c_target_addr(s, cmd.dev_index + i);
         union {
-            uint64_t pid:48;
-            uint8_t bcr;
-            uint8_t dcr;
+            uint64_t d;
             uint32_t w[2];
+            /* Per I3C spec: b[0]=PID MSB, b[5]=PID LSB, b[6]=BCR, b[7]=DCR */
             uint8_t b[8];
         } target_info;
 
@@ -1544,9 +1542,9 @@ static void dw_i3c_addr_assign_cmd(DWI3C *s, DWI3CAddrAssignCmd cmd)
             err = DW_I3C_RESP_QUEUE_ERR_DAA_NACK;
             break;
         }
-        dw_i3c_update_char_table(s, cmd.dev_index + i,
-                                            target_info.pid, target_info.bcr,
-                                            target_info.dcr, addr);
+        uint64_t pid = be64_to_cpu(target_info.d) >> 16;
+        dw_i3c_update_char_table(s, cmd.dev_index + i, pid, target_info.b[6],
+                                 target_info.b[7], addr);
 
         /* Push the PID, BCR, and DCR to the RX queue. */
         dw_i3c_push_rx(s, target_info.w[0]);
-- 
2.54.0