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arch/arm/mach-omap2/sdrc2xxx.c

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+/*
+ * linux/arch/arm/mach-omap2/sdrc2xxx.c
+ *
+ * SDRAM timing related functions for OMAP2xxx
+ *
+ * Copyright (C) 2005, 2008 Texas Instruments Inc.
+ * Copyright (C) 2005, 2008 Nokia Corporation
+ *
+ * Tony Lindgren <tony@atomide.com>
+ * Paul Walmsley
+ * Richard Woodruff <r-woodruff2@ti.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/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include "soc.h"
+#include "iomap.h"
+#include "common.h"
+#include "prm2xxx.h"
+#include "clock.h"
+#include "sdrc.h"
+#include "sram.h"
+
+/* Memory timing, DLL mode flags */
+#define M_DDR		1
+#define M_LOCK_CTRL	(1 << 2)
+#define M_UNLOCK	0
+#define M_LOCK		1
+
+
+static struct memory_timings mem_timings;
+static u32 curr_perf_level = CORE_CLK_SRC_DPLL_X2;
+
+static u32 omap2xxx_sdrc_get_slow_dll_ctrl(void)
+{
+	return mem_timings.slow_dll_ctrl;
+}
+
+static u32 omap2xxx_sdrc_get_fast_dll_ctrl(void)
+{
+	return mem_timings.fast_dll_ctrl;
+}
+
+static u32 omap2xxx_sdrc_get_type(void)
+{
+	return mem_timings.m_type;
+}
+
+/*
+ * Check the DLL lock state, and return tue if running in unlock mode.
+ * This is needed to compensate for the shifted DLL value in unlock mode.
+ */
+u32 omap2xxx_sdrc_dll_is_unlocked(void)
+{
+	/* dlla and dllb are a set */
+	u32 dll_state = sdrc_read_reg(SDRC_DLLA_CTRL);
+
+	if ((dll_state & (1 << 2)) == (1 << 2))
+		return 1;
+	else
+		return 0;
+}
+
+/*
+ * 'level' is the value to store to CM_CLKSEL2_PLL.CORE_CLK_SRC.
+ * Practical values are CORE_CLK_SRC_DPLL (for CORE_CLK = DPLL_CLK) or
+ * CORE_CLK_SRC_DPLL_X2 (for CORE_CLK = * DPLL_CLK * 2)
+ *
+ * Used by the clock framework during CORE DPLL changes
+ */
+u32 omap2xxx_sdrc_reprogram(u32 level, u32 force)
+{
+	u32 dll_ctrl, m_type;
+	u32 prev = curr_perf_level;
+	unsigned long flags;
+
+	if ((curr_perf_level == level) && !force)
+		return prev;
+
+	if (level == CORE_CLK_SRC_DPLL)
+		dll_ctrl = omap2xxx_sdrc_get_slow_dll_ctrl();
+	else if (level == CORE_CLK_SRC_DPLL_X2)
+		dll_ctrl = omap2xxx_sdrc_get_fast_dll_ctrl();
+	else
+		return prev;
+
+	m_type = omap2xxx_sdrc_get_type();
+
+	local_irq_save(flags);
+	/*
+	 * XXX These calls should be abstracted out through a
+	 * prm2xxx.c function
+	 */
+	if (cpu_is_omap2420())
+		__raw_writel(0xffff, OMAP2420_PRCM_VOLTSETUP);
+	else
+		__raw_writel(0xffff, OMAP2430_PRCM_VOLTSETUP);
+	omap2_sram_reprogram_sdrc(level, dll_ctrl, m_type);
+	curr_perf_level = level;
+	local_irq_restore(flags);
+
+	return prev;
+}
+
+/* Used by the clock framework during CORE DPLL changes */
+void omap2xxx_sdrc_init_params(u32 force_lock_to_unlock_mode)
+{
+	unsigned long dll_cnt;
+	u32 fast_dll = 0;
+
+	/* DDR = 1, SDR = 0 */
+	mem_timings.m_type = !((sdrc_read_reg(SDRC_MR_0) & 0x3) == 0x1);
+
+	/* 2422 es2.05 and beyond has a single SIP DDR instead of 2 like others.
+	 * In the case of 2422, its ok to use CS1 instead of CS0.
+	 */
+	if (cpu_is_omap2422())
+		mem_timings.base_cs = 1;
+	else
+		mem_timings.base_cs = 0;
+
+	if (mem_timings.m_type != M_DDR)
+		return;
+
+	/* With DDR we need to determine the low frequency DLL value */
+	if (((mem_timings.fast_dll_ctrl & (1 << 2)) == M_LOCK_CTRL))
+		mem_timings.dll_mode = M_UNLOCK;
+	else
+		mem_timings.dll_mode = M_LOCK;
+
+	if (mem_timings.base_cs == 0) {
+		fast_dll = sdrc_read_reg(SDRC_DLLA_CTRL);
+		dll_cnt = sdrc_read_reg(SDRC_DLLA_STATUS) & 0xff00;
+	} else {
+		fast_dll = sdrc_read_reg(SDRC_DLLB_CTRL);
+		dll_cnt = sdrc_read_reg(SDRC_DLLB_STATUS) & 0xff00;
+	}
+	if (force_lock_to_unlock_mode) {
+		fast_dll &= ~0xff00;
+		fast_dll |= dll_cnt;		/* Current lock mode */
+	}
+	/* set fast timings with DLL filter disabled */
+	mem_timings.fast_dll_ctrl = (fast_dll | (3 << 8));
+
+	/* No disruptions, DDR will be offline & C-ABI not followed */
+	omap2_sram_ddr_init(&mem_timings.slow_dll_ctrl,
+			    mem_timings.fast_dll_ctrl,
+			    mem_timings.base_cs,
+			    force_lock_to_unlock_mode);
+	mem_timings.slow_dll_ctrl &= 0xff00;	/* Keep lock value */
+
+	/* Turn status into unlock ctrl */
+	mem_timings.slow_dll_ctrl |=
+		((mem_timings.fast_dll_ctrl & 0xF) | (1 << 2));
+
+	/* 90 degree phase for anything below 133Mhz + disable DLL filter */
+	mem_timings.slow_dll_ctrl |= ((1 << 1) | (3 << 8));
+}