omap3: rx51: Add SDRAM init

This patch adds board specific SDRAM init for RX51. This patch is a
collaboration of work from following people:

Juha Yrjola: Original code
Lauri Leukkunen: Port to RX51
Tero Kristo: Support for multiple OPP:s, merge of patches
Samu Onkalo: Fixed SDRAM parameters according to specs
Kalle Jokiniemi: A fix for rounding error

Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Cc: Samu Onkalo <samu.p.onkalo@nokia.com>
Cc: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Cc: Lauri Leukkunen <lauri.leukkunen@nokia.com>
Cc: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

1 files changed, 221 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/board-rx51-sdram.c b/arch/arm/mach-omap2/board-rx51-sdram.c
new file mode 100644
index 000000000000..f392844195d2
--- /dev/null
+++ b/arch/arm/mach-omap2/board-rx51-sdram.c
@@ -0,0 +1,221 @@
+/*
+ * SDRC register values for RX51
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ *
+ * Lauri Leukkunen <lauri.leukkunen@nokia.com>
+ *
+ * Original code by Juha Yrjola <juha.yrjola@solidboot.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <plat/io.h>
+#include <plat/common.h>
+#include <plat/clock.h>
+#include <plat/sdrc.h>
+
+
+/* In picoseconds, except for tREF (ns), tXP, tCKE, tWTR (clks) */
+struct sdram_timings {
+	u32 casl;
+	u32 tDAL;
+	u32 tDPL;
+	u32 tRRD;
+	u32 tRCD;
+	u32 tRP;
+	u32 tRAS;
+	u32 tRC;
+	u32 tRFC;
+	u32 tXSR;
+
+	u32 tREF; /* in ns */
+
+	u32 tXP;
+	u32 tCKE;
+	u32 tWTR;
+};
+
+struct omap_sdrc_params rx51_sdrc_params[4];
+
+static const struct sdram_timings rx51_timings[] = {
+	{
+		.casl = 3,
+		.tDAL = 33000,
+		.tDPL = 15000,
+		.tRRD = 12000,
+		.tRCD = 22500,
+		.tRP = 18000,
+		.tRAS = 42000,
+		.tRC = 66000,
+		.tRFC = 138000,
+		.tXSR = 200000,
+
+		.tREF = 7800,
+
+		.tXP = 2,
+		.tCKE = 2,
+		.tWTR = 2
+	},
+};
+
+static unsigned long sdrc_get_fclk_period(long rate)
+{
+	/* In picoseconds */
+	return 1000000000 / rate;
+}
+
+static unsigned int sdrc_ps_to_ticks(unsigned int time_ps, long rate)
+{
+	unsigned long tick_ps;
+
+	/* Calculate in picosecs to yield more exact results */
+	tick_ps = sdrc_get_fclk_period(rate);
+
+	return (time_ps + tick_ps - 1) / tick_ps;
+}
+#undef DEBUG
+#ifdef DEBUG
+static int set_sdrc_timing_regval(u32 *regval, int st_bit, int end_bit,
+				int ticks, long rate, const char *name)
+#else
+static int set_sdrc_timing_regval(u32 *regval, int st_bit, int end_bit,
+			       int ticks)
+#endif
+{
+	int mask, nr_bits;
+
+	nr_bits = end_bit - st_bit + 1;
+	if (ticks >= 1 << nr_bits)
+		return -1;
+	mask = (1 << nr_bits) - 1;
+	*regval &= ~(mask << st_bit);
+	*regval |= ticks << st_bit;
+#ifdef DEBUG
+	printk(KERN_INFO "SDRC %s: %i ticks %i ns\n", name, ticks,
+			(unsigned int)sdrc_get_fclk_period(rate) * ticks /
+			1000);
+#endif
+
+	return 0;
+}
+
+#ifdef DEBUG
+#define SDRC_SET_ONE(reg, st, end, field, rate) \
+	if (set_sdrc_timing_regval((reg), (st), (end), \
+			rx51_timings->field, (rate), #field) < 0) \
+		err = -1;
+#else
+#define SDRC_SET_ONE(reg, st, end, field, rate) \
+	if (set_sdrc_timing_regval((reg), (st), (end), \
+			rx51_timings->field) < 0) \
+		err = -1;
+#endif
+
+#ifdef DEBUG
+static int set_sdrc_timing_regval_ps(u32 *regval, int st_bit, int end_bit,
+				int time, long rate, const char *name)
+#else
+static int set_sdrc_timing_regval_ps(u32 *regval, int st_bit, int end_bit,
+				int time, long rate)
+#endif
+{
+	int ticks, ret;
+	ret = 0;
+
+	if (time == 0)
+		ticks = 0;
+	else
+		ticks = sdrc_ps_to_ticks(time, rate);
+
+#ifdef DEBUG
+	ret = set_sdrc_timing_regval(regval, st_bit, end_bit, ticks,
+				     rate, name);
+#else
+	ret = set_sdrc_timing_regval(regval, st_bit, end_bit, ticks);
+#endif
+
+	return ret;
+}
+
+#ifdef DEBUG
+#define SDRC_SET_ONE_PS(reg, st, end, field, rate) \
+	if (set_sdrc_timing_regval_ps((reg), (st), (end), \
+			rx51_timings->field, \
+			(rate), #field) < 0) \
+		err = -1;
+
+#else
+#define SDRC_SET_ONE_PS(reg, st, end, field, rate) \
+	if (set_sdrc_timing_regval_ps((reg), (st), (end), \
+			rx51_timings->field, (rate)) < 0) \
+		err = -1;
+#endif
+
+static int sdrc_timings(int id, long rate)
+{
+	u32 ticks_per_ms;
+	u32 rfr, l;
+	u32 actim_ctrla = 0, actim_ctrlb = 0;
+	u32 rfr_ctrl;
+	int err = 0;
+	long l3_rate = rate / 1000;
+
+	SDRC_SET_ONE_PS(&actim_ctrla,  0,  4, tDAL, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla,  6,  8, tDPL, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla,  9, 11, tRRD, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla, 12, 14, tRCD, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla, 15, 17, tRP, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla, 18, 21, tRAS, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla, 22, 26, tRC, l3_rate);
+	SDRC_SET_ONE_PS(&actim_ctrla, 27, 31, tRFC, l3_rate);
+
+	SDRC_SET_ONE_PS(&actim_ctrlb,  0,  7, tXSR, l3_rate);
+
+	SDRC_SET_ONE(&actim_ctrlb,  8, 10, tXP, l3_rate);
+	SDRC_SET_ONE(&actim_ctrlb, 12, 14, tCKE, l3_rate);
+	SDRC_SET_ONE(&actim_ctrlb, 16, 17, tWTR, l3_rate);
+
+	ticks_per_ms = l3_rate;
+	rfr = rx51_timings[0].tREF * ticks_per_ms / 1000000;
+	if (rfr > 65535 + 50)
+		rfr = 65535;
+	else
+		rfr -= 50;
+
+#ifdef DEBUG
+	printk(KERN_INFO "SDRC tREF: %i ticks\n", rfr);
+#endif
+
+	l = rfr << 8;
+	rfr_ctrl = l | 0x1; /* autorefresh, reload counter with 1xARCV */
+
+	rx51_sdrc_params[id].rate = rate;
+	rx51_sdrc_params[id].actim_ctrla = actim_ctrla;
+	rx51_sdrc_params[id].actim_ctrlb = actim_ctrlb;
+	rx51_sdrc_params[id].rfr_ctrl = rfr_ctrl;
+	rx51_sdrc_params[id].mr = 0x32;
+
+	rx51_sdrc_params[id + 1].rate = 0;
+
+	return err;
+}
+
+struct omap_sdrc_params *rx51_get_sdram_timings(void)
+{
+	int err;
+
+	err = sdrc_timings(0, 41500000);
+	err |= sdrc_timings(1, 83000000);
+	err |= sdrc_timings(2, 166000000);
+
+	return &rx51_sdrc_params[0];
+}
+