xref: /openbmc/linux/arch/arm/mach-omap2/sdrc.c (revision d2912cb1)

// SPDX-License-Identifier: GPL-2.0-only
/*
 * SMS/SDRC (SDRAM controller) common code for OMAP2/3
 *
 * 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>
 */
#undef DEBUG

#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 "common.h"
#include "clock.h"
#include "sdrc.h"

static struct omap_sdrc_params *sdrc_init_params_cs0, *sdrc_init_params_cs1;

void __iomem *omap2_sdrc_base;
void __iomem *omap2_sms_base;

struct omap2_sms_regs {
	u32	sms_sysconfig;
};

static struct omap2_sms_regs sms_context;

/* SDRC_POWER register bits */
#define SDRC_POWER_EXTCLKDIS_SHIFT		3
#define SDRC_POWER_PWDENA_SHIFT			2
#define SDRC_POWER_PAGEPOLICY_SHIFT		0

/**
 * omap2_sms_save_context - Save SMS registers
 *
 * Save SMS registers that need to be restored after off mode.
 */
void omap2_sms_save_context(void)
{
	sms_context.sms_sysconfig = sms_read_reg(SMS_SYSCONFIG);
}

/**
 * omap2_sms_restore_context - Restore SMS registers
 *
 * Restore SMS registers that need to be Restored after off mode.
 */
void omap2_sms_restore_context(void)
{
	sms_write_reg(sms_context.sms_sysconfig, SMS_SYSCONFIG);
}

/**
 * omap2_sdrc_get_params - return SDRC register values for a given clock rate
 * @r: SDRC clock rate (in Hz)
 * @sdrc_cs0: chip select 0 ram timings **
 * @sdrc_cs1: chip select 1 ram timings **
 *
 * Return pre-calculated values for the SDRC_ACTIM_CTRLA,
 *  SDRC_ACTIM_CTRLB, SDRC_RFR_CTRL and SDRC_MR registers in sdrc_cs[01]
 *  structs,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.
 *
 * Supports 2 different timing parameters for both chip selects.
 *
 * Note 1: the sdrc_init_params_cs[01] must be sorted rate descending.
 * Note 2: If sdrc_init_params_cs_1 is not NULL it must be of same size
 *  as sdrc_init_params_cs_0.
 *
 * Fills in the struct omap_sdrc_params * for each chip select.
 * Returns 0 upon success or -1 upon failure.
 */
int omap2_sdrc_get_params(unsigned long r,
			  struct omap_sdrc_params **sdrc_cs0,
			  struct omap_sdrc_params **sdrc_cs1)
{
	struct omap_sdrc_params *sp0, *sp1;

	if (!sdrc_init_params_cs0)
		return -1;

	sp0 = sdrc_init_params_cs0;
	sp1 = sdrc_init_params_cs1;

	while (sp0->rate && sp0->rate != r) {
		sp0++;
		if (sdrc_init_params_cs1)
			sp1++;
	}

	if (!sp0->rate)
		return -1;

	*sdrc_cs0 = sp0;
	*sdrc_cs1 = sp1;
	return 0;
}


void __init omap2_set_globals_sdrc(void __iomem *sdrc, void __iomem *sms)
{
	omap2_sdrc_base = sdrc;
	omap2_sms_base = sms;
}

/**
 * omap2_sdrc_init - initialize SMS, SDRC devices on boot
 * @sdrc_cs[01]: pointers to a null-terminated list of struct omap_sdrc_params
 *  Support for 2 chip selects timings
 *
 * Turn on smart idle modes for SDRAM scheduler and controller.
 * Program a known-good configuration for the SDRC to deal with buggy
 * bootloaders.
 */
void __init omap2_sdrc_init(struct omap_sdrc_params *sdrc_cs0,
			    struct omap_sdrc_params *sdrc_cs1)
{
	u32 l;

	l = sms_read_reg(SMS_SYSCONFIG);
	l &= ~(0x3 << 3);
	l |= (0x2 << 3);
	sms_write_reg(l, SMS_SYSCONFIG);

	l = sdrc_read_reg(SDRC_SYSCONFIG);
	l &= ~(0x3 << 3);
	l |= (0x2 << 3);
	sdrc_write_reg(l, SDRC_SYSCONFIG);

	sdrc_init_params_cs0 = sdrc_cs0;
	sdrc_init_params_cs1 = sdrc_cs1;

	/* XXX Enable SRFRONIDLEREQ here also? */
	/*
	 * PWDENA should not be set due to 34xx erratum 1.150 - PWDENA
	 * can cause random memory corruption
	 */
	l = (1 << SDRC_POWER_EXTCLKDIS_SHIFT) |
		(1 << SDRC_POWER_PAGEPOLICY_SHIFT);
	sdrc_write_reg(l, SDRC_POWER);
	omap2_sms_save_context();
}