[Qemu-devel] [PATCH V5 7/7] Fix NOR flash device ID reading

[Roy Franz <roy.franz@linaro.org>]

Fix NOR flash manufacturer and device ID reading.  This now
properly takes into account device widths and device max widths
as required.  The reading of these IDs uses the same max_width
dependent addressing as CFI queries.

The old code remains for chips that don't specify a device width,
as the new code relies on a device width being set in order to
properly operate.  The existing code seems very broken.

Only ident0 and ident1 are used in the new code, as other fields
relate to the lock state of blocks in flash.

The VExpress flash configuration has been updated to match
the new code, as the existing definition was 'wrong' in order
to return the expected results with the broken device ID code.

Signed-off-by: Roy Franz <roy.franz@linaro.org>
---
 hw/arm/vexpress.c       |    6 +--
 hw/block/pflash_cfi01.c |  107 ++++++++++++++++++++++++++++++++++++++---------
 2 files changed, 90 insertions(+), 23 deletions(-)

diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
index 939b468..aaa863e 100644
--- a/hw/arm/vexpress.c
+++ b/hw/arm/vexpress.c
@@ -499,10 +499,10 @@ static pflash_t *ve_pflash_cfi01_register(hwaddr base, const char *name,
     qdev_prop_set_uint8(dev, "width", 4);
     qdev_prop_set_uint8(dev, "device-width", 2);
     qdev_prop_set_uint8(dev, "big-endian", 0);
-    qdev_prop_set_uint16(dev, "id0", 0x00);
-    qdev_prop_set_uint16(dev, "id1", 0x89);
+    qdev_prop_set_uint16(dev, "id0", 0x89);
+    qdev_prop_set_uint16(dev, "id1", 0x18);
     qdev_prop_set_uint16(dev, "id2", 0x00);
-    qdev_prop_set_uint16(dev, "id3", 0x18);
+    qdev_prop_set_uint16(dev, "id3", 0x00);
     qdev_prop_set_string(dev, "name", name);
     qdev_init_nofail(dev);
 
diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index 564e6ee..15e4a64 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -179,6 +179,58 @@ static uint32_t pflash_cfi_query(pflash_t *pfl, hwaddr offset)
     return resp;
 }
 
+
+
+/* Perform a device id query based on the bank width of the flash. */
+static uint32_t pflash_devid_query(pflash_t *pfl, hwaddr offset)
+{
+    int i;
+    uint32_t resp;
+    hwaddr boff;
+
+    /* Adjust incoming offset to match expected device-width
+     * addressing. Device ID read addresses are always specified in
+     * terms of the maximum supported width of the device.  This means
+     * that x8 devices and x8/x16 devices in x8 mode behave
+     * differently. For devices that are not used at their max width,
+     * we will be provided with addresses that use higher address bits
+     * than expected (based on the max width), so we will shift them
+     * lower so that they will match the addresses used when
+     * device_width==max_device_width.
+     */
+    boff = offset >> (ctz32(pfl->bank_width) +
+                      ctz32(pfl->max_device_width) - ctz32(pfl->device_width));
+
+    /* Mask off upper bits which may be used in to query block
+     * or sector lock status at other addresses.
+     * Offsets 2/3 are block lock status, is not emulated.
+     */
+    switch (boff & 0xFF) {
+    case 0:
+        resp = pfl->ident0;
+        DPRINTF("%s: Manufacturer Code %04x\n", __func__, ret);
+        break;
+    case 1:
+        resp = pfl->ident1;
+        DPRINTF("%s: Device ID Code %04x\n", __func__, ret);
+        break;
+    default:
+        DPRINTF("%s: Read Device Information offset=%x\n", __func__,
+                (unsigned)offset);
+        return 0;
+        break;
+    }
+    /* Replicate responses for each device in bank. */
+    if (pfl->device_width < pfl->bank_width) {
+        for (i = pfl->device_width;
+              i < pfl->bank_width; i += pfl->device_width) {
+            resp = deposit32(resp, 8 * i, 8 * pfl->device_width, resp);
+        }
+    }
+
+    return resp;
+}
+
 static uint32_t pflash_read (pflash_t *pfl, hwaddr offset,
                              int width, int be)
 {
@@ -266,26 +318,41 @@ static uint32_t pflash_read (pflash_t *pfl, hwaddr offset,
         DPRINTF("%s: status %x\n", __func__, ret);
         break;
     case 0x90:
-        boff = offset & 0xFF;
-        if (pfl->bank_width == 2)
-            boff = boff >> 1;
-        else if (pfl->bank_width == 4)
-            boff = boff >> 2;
-
-        switch (boff) {
-        case 0:
-            ret = pfl->ident0 << 8 | pfl->ident1;
-            DPRINTF("%s: Manufacturer Code %04x\n", __func__, ret);
-            break;
-        case 1:
-            ret = pfl->ident2 << 8 | pfl->ident3;
-            DPRINTF("%s: Device ID Code %04x\n", __func__, ret);
-            break;
-        default:
-            DPRINTF("%s: Read Device Information boff=%x\n", __func__,
-                    (unsigned)boff);
-            ret = 0;
-            break;
+
+        if (!pfl->device_width) {
+            /* Preserve old behavior if device width not specified */
+            boff = offset & 0xFF;
+            if (pfl->bank_width == 2) {
+                boff = boff >> 1;
+            } else if (pfl->bank_width == 4) {
+                boff = boff >> 2;
+            }
+
+            switch (boff) {
+            case 0:
+                ret = pfl->ident0 << 8 | pfl->ident1;
+                DPRINTF("%s: Manufacturer Code %04x\n", __func__, ret);
+                break;
+            case 1:
+                ret = pfl->ident2 << 8 | pfl->ident3;
+                DPRINTF("%s: Device ID Code %04x\n", __func__, ret);
+                break;
+            default:
+                DPRINTF("%s: Read Device Information boff=%x\n", __func__,
+                        (unsigned)boff);
+                ret = 0;
+                break;
+            }
+        } else {
+            /* If we have a read larger than the bank_width, combine multiple
+             * manufacturer/device ID queries into a single response.
+             */
+            int i;
+            for (i = 0; i < width; i += pfl->bank_width) {
+                ret = deposit32(ret, i * 8, pfl->bank_width * 8,
+                                pflash_devid_query(pfl,
+                                                 offset + i * pfl->bank_width));
+            }
         }
         break;
     case 0x98: /* Query mode */
-- 
1.7.10.4