1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * LPC32xx dram init
4 *
5 * (C) Copyright 2014 DENX Software Engineering GmbH
6 * Written-by: Albert ARIBAUD <albert.aribaud@3adev.fr>
7 *
8 * This is called by SPL to gain access to the SDR DRAM.
9 *
10 * This code runs from SRAM.
11 */
12
13 #include <common.h>
14 #include <netdev.h>
15 #include <asm/arch/cpu.h>
16 #include <asm/arch/clk.h>
17 #include <asm/arch/wdt.h>
18 #include <asm/arch/emc.h>
19 #include <asm/io.h>
20 #include <linux/delay.h>
21
22 static struct clk_pm_regs *clk = (struct clk_pm_regs *)CLK_PM_BASE;
23 static struct emc_regs *emc = (struct emc_regs *)EMC_BASE;
24
ddr_init(struct emc_dram_settings * dram)25 void ddr_init(struct emc_dram_settings *dram)
26 {
27 uint32_t ck;
28
29 /* Enable EMC interface and choose little endian mode */
30 writel(1, &emc->ctrl);
31 writel(0, &emc->config);
32 /* Select maximum EMC Dynamic Memory Refresh Time */
33 writel(0x7FF, &emc->refresh);
34 /* Determine CLK */
35 ck = get_sdram_clk_rate();
36 /* Configure SDRAM */
37 writel(dram->cmddelay, &clk->sdramclk_ctrl);
38 writel(dram->config0, &emc->config0);
39 writel(dram->rascas0, &emc->rascas0);
40 writel(dram->rdconfig, &emc->read_config);
41 /* Set timings */
42 writel((ck / dram->trp) & 0x0000000F, &emc->t_rp);
43 writel((ck / dram->tras) & 0x0000000F, &emc->t_ras);
44 writel((ck / dram->tsrex) & 0x0000007F, &emc->t_srex);
45 writel((ck / dram->twr) & 0x0000000F, &emc->t_wr);
46 writel((ck / dram->trc) & 0x0000001F, &emc->t_rc);
47 writel((ck / dram->trfc) & 0x0000001F, &emc->t_rfc);
48 writel((ck / dram->txsr) & 0x000000FF, &emc->t_xsr);
49 writel(dram->trrd, &emc->t_rrd);
50 writel(dram->tmrd, &emc->t_mrd);
51 writel(dram->tcdlr, &emc->t_cdlr);
52 /* Dynamic refresh */
53 writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
54 udelay(10);
55 /* Force all clocks, enable inverted ck, issue NOP command */
56 writel(0x00000193, &emc->control);
57 udelay(100);
58 /* Keep all clocks enabled, issue a PRECHARGE ALL command */
59 writel(0x00000113, &emc->control);
60 /* Fast dynamic refresh for at least a few SDRAM ck cycles */
61 writel((((128) >> 4) & 0x7FF), &emc->refresh);
62 udelay(10);
63 /* set correct dynamic refresh timing */
64 writel((((ck / dram->refresh) >> 4) & 0x7FF), &emc->refresh);
65 udelay(10);
66 /* set normal mode to CAS=3 */
67 writel(0x00000093, &emc->control);
68 readl(EMC_DYCS0_BASE | dram->mode);
69 /* set extended mode to all zeroes */
70 writel(0x00000093, &emc->control);
71 readl(EMC_DYCS0_BASE | dram->emode);
72 /* stop forcing clocks, keep inverted clock, issue normal mode */
73 writel(0x00000010, &emc->control);
74 }
75