[Qemu-devel] [PATCH v2 2/9] hw/block/pflash_cfi01: Use the correct READ_ARRAY value

[Philippe Mathieu-Daudé]

In the "Read Array Flowchart" the command has a value of 0xFF.

In the document [*] the "Read Array Flowchart", the READ_ARRAY
command has a value of 0xff.

Use the correct value in the pflash model.

There is no change of behavior in the guest, because:
- when the guest were sending 0xFF, the reset_flash label
  was setting the command value as 0x00
- 0x00 was used internally for READ_ARRAY

[*] "Common Flash Interface (CFI) and Command Sets"
    (Intel Application Note 646)
    Appendix B "Basic Command Set"

Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com>
---
 hw/block/pflash_cfi01.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index dcc9885bf0..743b5d5794 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -280,10 +280,9 @@ static uint32_t pflash_read(PFlashCFI01 *pfl, hwaddr 
offset,
         /* This should never happen : reset state & treat it as a read */
         DPRINTF("%s: unknown command state: %x\n", __func__, pfl->cmd);
         pfl->wcycle = 0;
-        pfl->cmd = 0;
+        pfl->cmd = 0xff;
         /* fall through to read code */
-    case 0x00:
-        /* Flash area read */
+    case 0xff: /* Read Array */
         ret = pflash_data_read(pfl, offset, width, be);
         break;
     case 0x10: /* Single byte program */
@@ -449,8 +448,6 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
     case 0:
         /* read mode */
         switch (cmd) {
-        case 0x00: /* ??? */
-            goto reset_flash;
         case 0x10: /* Single Byte Program */
         case 0x40: /* Single Byte Program */
             DPRINTF("%s: Single Byte Program\n", __func__);
@@ -527,7 +524,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
             if (cmd == 0xd0) { /* confirm */
                 pfl->wcycle = 0;
                 pfl->status |= 0x80;
-            } else if (cmd == 0xff) { /* read array mode */
+            } else if (cmd == 0xff) { /* Read Array */
                 goto reset_flash;
             } else
                 goto error_flash;
@@ -554,7 +551,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
             } else if (cmd == 0x01) {
                 pfl->wcycle = 0;
                 pfl->status |= 0x80;
-            } else if (cmd == 0xff) {
+            } else if (cmd == 0xff) { /* read array mode */
                 goto reset_flash;
             } else {
                 DPRINTF("%s: Unknown (un)locking command\n", __func__);
@@ -646,7 +643,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
     trace_pflash_reset();
     memory_region_rom_device_set_romd(&pfl->mem, true);
     pfl->wcycle = 0;
-    pfl->cmd = 0;
+    pfl->cmd = 0xff;
 }
 
 
@@ -762,7 +759,7 @@ static void pflash_cfi01_realize(DeviceState *dev, Error 
**errp)
     }
 
     pfl->wcycle = 0;
-    pfl->cmd = 0;
+    pfl->cmd = 0xff;
     pfl->status = 0;
     /* Hardcoded CFI table */
     /* Standard "QRY" string */
-- 
2.20.1