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/*
* (C) Copyright 2017
* Vikas Manocha, <vikas.manocha@st.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/io.h>
#include <asm/arch/fmc.h>
#include <asm/arch/stm32.h>
static inline u32 _ns2clk(u32 ns, u32 freq)
{
u32 tmp = freq/1000000;
return (tmp * ns) / 1000;
}
#define NS2CLK(ns) (_ns2clk(ns, freq))
/*
* Following are timings for IS42S16400J, from corresponding datasheet
*/
#define SDRAM_CAS 3 /* 3 cycles */
#define SDRAM_NB 1 /* Number of banks */
#define SDRAM_MWID 1 /* 16 bit memory */
#define SDRAM_NR 0x1 /* 12-bit row */
#define SDRAM_NC 0x0 /* 8-bit col */
#define SDRAM_RBURST 0x1 /* Single read requests always as bursts */
#define SDRAM_RPIPE 0x0 /* No HCLK clock cycle delay */
#define SDRAM_TRRD NS2CLK(12)
#define SDRAM_TRCD NS2CLK(18)
#define SDRAM_TRP NS2CLK(18)
#define SDRAM_TRAS NS2CLK(42)
#define SDRAM_TRC NS2CLK(60)
#define SDRAM_TRFC NS2CLK(60)
#define SDRAM_TCDL (1 - 1)
#define SDRAM_TRDL NS2CLK(12)
#define SDRAM_TBDL (1 - 1)
#define SDRAM_TREF (NS2CLK(64000000 / 8192) - 20)
#define SDRAM_TCCD (1 - 1)
#define SDRAM_TXSR SDRAM_TRFC /* Row cycle time after precharge */
#define SDRAM_TMRD 1 /* Page 10, Mode Register Set */
/* Last data in to row precharge, need also comply ineq on page 1648 */
#define SDRAM_TWR max(\
(int)max((int)SDRAM_TRDL, (int)(SDRAM_TRAS - SDRAM_TRCD)), \
(int)(SDRAM_TRC - SDRAM_TRCD - SDRAM_TRP)\
)
#define SDRAM_MODE_BL_SHIFT 0
#define SDRAM_MODE_CAS_SHIFT 4
#define SDRAM_MODE_BL 0
#define SDRAM_MODE_CAS SDRAM_CAS
int stm32_sdram_init(void)
{
u32 freq;
/*
* Get frequency for NS2CLK calculation.
*/
freq = clock_get(CLOCK_AHB) / CONFIG_SYS_RAM_FREQ_DIV;
writel(CONFIG_SYS_RAM_FREQ_DIV << FMC_SDCR_SDCLK_SHIFT
| SDRAM_CAS << FMC_SDCR_CAS_SHIFT
| SDRAM_NB << FMC_SDCR_NB_SHIFT
| SDRAM_MWID << FMC_SDCR_MWID_SHIFT
| SDRAM_NR << FMC_SDCR_NR_SHIFT
| SDRAM_NC << FMC_SDCR_NC_SHIFT
| SDRAM_RPIPE << FMC_SDCR_RPIPE_SHIFT
| SDRAM_RBURST << FMC_SDCR_RBURST_SHIFT,
&STM32_SDRAM_FMC->sdcr1);
writel(SDRAM_TRCD << FMC_SDTR_TRCD_SHIFT
| SDRAM_TRP << FMC_SDTR_TRP_SHIFT
| SDRAM_TWR << FMC_SDTR_TWR_SHIFT
| SDRAM_TRC << FMC_SDTR_TRC_SHIFT
| SDRAM_TRAS << FMC_SDTR_TRAS_SHIFT
| SDRAM_TXSR << FMC_SDTR_TXSR_SHIFT
| SDRAM_TMRD << FMC_SDTR_TMRD_SHIFT,
&STM32_SDRAM_FMC->sdtr1);
writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK,
&STM32_SDRAM_FMC->sdcmr);
udelay(200); /* 200 us delay, page 10, "Power-Up" */
FMC_BUSY_WAIT();
writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE,
&STM32_SDRAM_FMC->sdcmr);
udelay(100);
FMC_BUSY_WAIT();
writel((FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_AUTOREFRESH
| 7 << FMC_SDCMR_NRFS_SHIFT), &STM32_SDRAM_FMC->sdcmr);
udelay(100);
FMC_BUSY_WAIT();
writel(FMC_SDCMR_BANK_1 | (SDRAM_MODE_BL << SDRAM_MODE_BL_SHIFT
| SDRAM_MODE_CAS << SDRAM_MODE_CAS_SHIFT)
<< FMC_SDCMR_MODE_REGISTER_SHIFT | FMC_SDCMR_MODE_WRITE_MODE,
&STM32_SDRAM_FMC->sdcmr);
udelay(100);
FMC_BUSY_WAIT();
writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL,
&STM32_SDRAM_FMC->sdcmr);
FMC_BUSY_WAIT();
/* Refresh timer */
writel(SDRAM_TREF, &STM32_SDRAM_FMC->sdrtr);
return 0;
}
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