[PATCH qemu v3 1/2] hw/at24c : modify at24c to support 1 byte address mode

[~ssinprem]

From: Sittisak Sinprem <ssinp...@celestica.com>

Signed-off-by: Sittisak Sinprem <ssinp...@celestica.com>
---
 hw/nvram/eeprom_at24c.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index 3328c32814..64259cde67 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -41,6 +41,12 @@ struct EEPROMState {
     uint16_t cur;
     /* total size in bytes */
     uint32_t rsize;
+    /* address byte number 
+     *  for  24c01, 24c02 size <= 256 byte, use only 1 byte
+     *  otherwise size > 256, use 2 byte
+     */
+    uint8_t asize;
+
     bool writable;
     /* cells changed since last START? */
     bool changed;
@@ -91,7 +97,10 @@ uint8_t at24c_eeprom_recv(I2CSlave *s)
     EEPROMState *ee = AT24C_EE(s);
     uint8_t ret;
 
-    if (ee->haveaddr == 1) {
+    /* If got the byte address but not completely with address size
+     *  will return the invalid value
+     */
+    if (ee->haveaddr > 0 && ee->haveaddr < ee->asize) {
         return 0xff;
     }
 
@@ -108,11 +117,11 @@ int at24c_eeprom_send(I2CSlave *s, uint8_t data)
 {
     EEPROMState *ee = AT24C_EE(s);
 
-    if (ee->haveaddr < 2) {
+    if (ee->haveaddr < ee->asize) {
         ee->cur <<= 8;
         ee->cur |= data;
         ee->haveaddr++;
-        if (ee->haveaddr == 2) {
+        if (ee->haveaddr == ee->asize) {
             ee->cur %= ee->rsize;
             DPRINTK("Set pointer %04x\n", ee->cur);
         }
@@ -199,6 +208,18 @@ static void at24c_eeprom_realize(DeviceState *dev, Error 
**errp)
         }
         DPRINTK("Reset read backing file\n");
     }
+
+    /*
+     * If address size didn't define with property set
+     *   value is 0 as default, setting it by Rom size detecting.
+     */
+    if (ee->asize == 0) {
+        if (ee->rsize <= 256) {
+            ee->asize = 1;
+        } else {
+            ee->asize = 2;
+        }
+    }
 }
 
 static
@@ -213,6 +234,7 @@ void at24c_eeprom_reset(DeviceState *state)
 
 static Property at24c_eeprom_props[] = {
     DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
+    DEFINE_PROP_UINT8("address-size", EEPROMState, asize, 0),
     DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
     DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
     DEFINE_PROP_END_OF_LIST()
-- 
2.34.6