Merge branch 'master' into hpc2

[karo-tx-uboot.git] / common / cmd_eeprom.c

diff --git a/common/cmd_eeprom.c b/common/cmd_eeprom.c
index 80b8ccc1e8d08d0d695254a6ab13314fbf5d8256..d15a4120577f617744487b25c95b8c4c84f9b764 100644 (file)
--- a/common/cmd_eeprom.c
+++ b/common/cmd_eeprom.c
@@ -22,6 +22,21 @@
  *
  */
 
+/*
+ * Support for read and write access to EEPROM like memory devices. This
+ * includes regular EEPROM as well as  FRAM (ferroelectic nonvolaile RAM).
+ * FRAM devices read and write data at bus speed. In particular, there is no
+ * write delay. Also, there is no limit imposed on the numer of bytes that can
+ * be transferred with a single read or write.
+ *
+ * Use the following configuration options to ensure no unneeded performance
+ * degradation (typical for EEPROM) is incured for FRAM memory:
+ *
+ * #define CFG_I2C_FRAM
+ * #undef CFG_EEPROM_PAGE_WRITE_DELAY_MS
+ *
+ */
+
 #include <common.h>
 #include <config.h>
 #include <command.h>
@@ -34,6 +49,9 @@ extern int  eeprom_read  (unsigned dev_addr, unsigned offset,
                          uchar *buffer, unsigned cnt);
 extern int  eeprom_write (unsigned dev_addr, unsigned offset,
                          uchar *buffer, unsigned cnt);
+#if defined(CFG_EEPROM_WREN)
+extern int eeprom_write_enable (unsigned dev_addr, int state);
+#endif
 #endif
 
 
@@ -122,7 +140,11 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt
         * because the next page may be in a different device.
         */
        while (offset < end) {
-               unsigned alen, len, maxlen;
+               unsigned alen, len;
+#if !defined(CFG_I2C_FRAM)
+               unsigned maxlen;
+#endif
+
 #if CFG_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X)
                uchar addr[2];
 
@@ -144,12 +166,21 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt
 
                addr[0] |= dev_addr;            /* insert device address */
 
+               len = end - offset;
+
+               /*
+                * For a FRAM device there is no limit on the number of the
+                * bytes that can be ccessed with the single read or write
+                * operation.
+                */
+#if !defined(CFG_I2C_FRAM)
                maxlen = 0x100 - blk_off;
                if (maxlen > I2C_RXTX_LEN)
                        maxlen = I2C_RXTX_LEN;
-               len    = end - offset;
                if (len > maxlen)
                        len = maxlen;
+#endif
+
 #ifdef CONFIG_SPI
                spi_read (addr, alen, buffer, len);
 #else
@@ -159,6 +190,7 @@ int eeprom_read (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cnt
                buffer += len;
                offset += len;
        }
+
        return rcode;
 }
 
@@ -185,13 +217,20 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
        int     i;
 #endif
 
+#if defined(CFG_EEPROM_WREN)
+       eeprom_write_enable (dev_addr,1);
+#endif
        /* Write data until done or would cross a write page boundary.
         * We must write the address again when changing pages
         * because the address counter only increments within a page.
         */
 
        while (offset < end) {
-               unsigned alen, len, maxlen;
+               unsigned alen, len;
+#if !defined(CFG_I2C_FRAM)
+               unsigned maxlen;
+#endif
+
 #if CFG_I2C_EEPROM_ADDR_LEN == 1 && !defined(CONFIG_SPI_X)
                uchar addr[2];
 
@@ -213,6 +252,15 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
 
                addr[0] |= dev_addr;            /* insert device address */
 
+               len = end - offset;
+
+               /*
+                * For a FRAM device there is no limit on the number of the
+                * bytes that can be ccessed with the single read or write
+                * operation.
+                */
+#if !defined(CFG_I2C_FRAM)
+
 #if defined(CFG_EEPROM_PAGE_WRITE_BITS)
 
 #define        EEPROM_PAGE_SIZE        (1 << CFG_EEPROM_PAGE_WRITE_BITS)
@@ -225,9 +273,10 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
                if (maxlen > I2C_RXTX_LEN)
                        maxlen = I2C_RXTX_LEN;
 
-               len = end - offset;
                if (len > maxlen)
                        len = maxlen;
+#endif
+
 #ifdef CONFIG_SPI
                spi_write (addr, alen, buffer, len);
 #else
@@ -324,6 +373,9 @@ int eeprom_write (unsigned dev_addr, unsigned offset, uchar *buffer, unsigned cn
                udelay(CFG_EEPROM_PAGE_WRITE_DELAY_MS * 1000);
 #endif
        }
+#if defined(CFG_EEPROM_WREN)
+       eeprom_write_enable (dev_addr,0);
+#endif
        return rcode;
 }