powerpc/82xx: add SDRAM detection for km82xx

This patch adds SDRAM detection feature to km82xx boards.
To enable this feature, define CONFIG_SYS_SDRAM_LIST as the initializer
for an array of struct sdram_conf_s.
These structs will expose the bitfields within registers PSDMR and OR1 which
have to be different between configurations; common bitfields will be
defined, as usual, within CONFIG_SYS_PSDMR and CONFIG_SYS_OR1.
If CONFIG_SYS_SDRAM_LIST is not defined, then the usual behavior is retained.

Signed-off-by: Gerlando Falauto <gerlando.falauto@keymile.com>

diff --git a/board/keymile/km82xx/km82xx.c b/board/keymile/km82xx/km82xx.c
index 0e50b0bfa0726ff7941c2310373e8d103414facb..67b69f6cb34712d807bb7bace1a930c518a690c7 100644 (file)
--- a/board/keymile/km82xx/km82xx.c
+++ b/board/keymile/km82xx/km82xx.c
@@ -261,6 +261,54 @@ static long int try_init(memctl8260_t *memctl, ulong sdmr,
        return size;
 }
 
+#ifdef CONFIG_SYS_SDRAM_LIST
+
+/*
+ * If CONFIG_SYS_SDRAM_LIST is defined, we cycle through all SDRAM
+ * configurations therein (should be from high to lower) to find the
+ * one actually matching the current configuration.
+ * CONFIG_SYS_PSDMR and CONFIG_SYS_OR1 will contain the base values which are
+ * common among all possible configurations; values in CONFIG_SYS_SDRAM_LIST
+ * (defined as the initialization value for the array of struct sdram_conf_s)
+ * will then be ORed with such base values.
+ */
+
+struct sdram_conf_s {
+       ulong size;
+       int or1;
+       int psdmr;
+};
+
+static struct sdram_conf_s sdram_conf[] = CONFIG_SYS_SDRAM_LIST;
+
+static long probe_sdram(memctl8260_t *memctl)
+{
+       int n = 0;
+       long psize = 0;
+
+       for (n = 0; n < ARRAY_SIZE(sdram_conf); psize = 0, n++) {
+               psize = try_init(memctl,
+                       CONFIG_SYS_PSDMR | sdram_conf[n].psdmr,
+                       CONFIG_SYS_OR1 | sdram_conf[n].or1,
+                       (uchar *) CONFIG_SYS_SDRAM_BASE);
+               debug("Probing %ld bytes returned %ld\n",
+                       sdram_conf[n].size, psize);
+               if (psize == sdram_conf[n].size)
+                       break;
+       }
+       return psize;
+}
+
+#else /* CONFIG_SYS_SDRAM_LIST */
+
+static long probe_sdram(memctl8260_t *memctl)
+{
+       return try_init(memctl, CONFIG_SYS_PSDMR, CONFIG_SYS_OR1,
+                                       (uchar *) CONFIG_SYS_SDRAM_BASE);
+}
+#endif /* CONFIG_SYS_SDRAM_LIST */
+
+
 phys_size_t initdram(int board_type)
 {
        immap_t *immap = (immap_t *) CONFIG_SYS_IMMR;
@@ -274,8 +322,7 @@ phys_size_t initdram(int board_type)
 #ifndef CONFIG_SYS_RAMBOOT
        /* 60x SDRAM setup:
         */
-       psize = try_init(memctl, CONFIG_SYS_PSDMR, CONFIG_SYS_OR1,
-                                 (uchar *) CONFIG_SYS_SDRAM_BASE);
+       psize = probe_sdram(memctl);
 #endif /* CONFIG_SYS_RAMBOOT */
 
        icache_enable();