[ARM] OMAP2 SDRC: add SDRAM timing parameter infrastructure

[linux-2.6-omap-h63xx.git] / arch / arm / mach-omap2 / sdrc.c

diff --git a/arch/arm/mach-omap2/sdrc.c b/arch/arm/mach-omap2/sdrc.c
index 24b54d50b893f6af19492bad4592ab5a41500f14..2a30060cb4b78ec897bb668b31c665c26c160827 100644 (file)
--- a/arch/arm/mach-omap2/sdrc.c
+++ b/arch/arm/mach-omap2/sdrc.c
@@ -12,6 +12,7 @@
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
+#undef DEBUG
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -31,9 +32,42 @@
 #include <mach/sdrc.h>
 #include "sdrc.h"
 
+static struct omap_sdrc_params *sdrc_init_params;
+
 void __iomem *omap2_sdrc_base;
 void __iomem *omap2_sms_base;
 
+
+/**
+ * omap2_sdrc_get_params - return SDRC register values for a given clock rate
+ * @r: SDRC clock rate (in Hz)
+ *
+ * Return pre-calculated values for the SDRC_ACTIM_CTRLA,
+ * SDRC_ACTIM_CTRLB, SDRC_RFR_CTRL, and SDRC_MR registers, for a given
+ * SDRC clock rate 'r'.  These parameters control various timing
+ * delays in the SDRAM controller that are expressed in terms of the
+ * number of SDRC clock cycles to wait; hence the clock rate
+ * dependency. Note that sdrc_init_params must be sorted rate
+ * descending.  Also assumes that both chip-selects use the same
+ * timing parameters.  Returns a struct omap_sdrc_params * upon
+ * success, or NULL upon failure.
+ */
+struct omap_sdrc_params *omap2_sdrc_get_params(unsigned long r)
+{
+       struct omap_sdrc_params *sp;
+
+       sp = sdrc_init_params;
+
+       while (sp->rate != r)
+               sp++;
+
+       if (!sp->rate)
+               return NULL;
+
+       return sp;
+}
+
+
 void __init omap2_set_globals_sdrc(struct omap_globals *omap2_globals)
 {
        omap2_sdrc_base = omap2_globals->sdrc;
@@ -41,7 +75,7 @@ void __init omap2_set_globals_sdrc(struct omap_globals *omap2_globals)
 }
 
 /* turn on smart idle modes for SDRAM scheduler and controller */
-void __init omap2_sdrc_init(void)
+void __init omap2_sdrc_init(struct omap_sdrc_params *sp)
 {
        u32 l;
 
@@ -54,4 +88,6 @@ void __init omap2_sdrc_init(void)
        l &= ~(0x3 << 3);
        l |= (0x2 << 3);
        sdrc_write_reg(l, SDRC_SYSCONFIG);
+
+       sdrc_init_params = sp;
 }