xref: /openbmc/u-boot/drivers/ram/stm32_sdram.c (revision e30d2bd4)
1 /*
2  * (C) Copyright 2017
3  * Vikas Manocha, <vikas.manocha@st.com>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <clk.h>
10 #include <dm.h>
11 #include <ram.h>
12 #include <asm/io.h>
13 #include <asm/arch/fmc.h>
14 #include <asm/arch/stm32.h>
15 
16 DECLARE_GLOBAL_DATA_PTR;
17 
18 struct stm32_sdram_control {
19 	u8 no_columns;
20 	u8 no_rows;
21 	u8 memory_width;
22 	u8 no_banks;
23 	u8 cas_latency;
24 	u8 sdclk;
25 	u8 rd_burst;
26 	u8 rd_pipe_delay;
27 };
28 
29 struct stm32_sdram_timing {
30 	u8 tmrd;
31 	u8 txsr;
32 	u8 tras;
33 	u8 trc;
34 	u8 trp;
35 	u8 twr;
36 	u8 trcd;
37 };
38 struct stm32_sdram_params {
39 	u8 no_sdram_banks;
40 	struct stm32_sdram_control sdram_control;
41 	struct stm32_sdram_timing sdram_timing;
42 	u32 sdram_ref_count;
43 };
44 
45 #define SDRAM_MODE_BL_SHIFT	0
46 #define SDRAM_MODE_CAS_SHIFT	4
47 #define SDRAM_MODE_BL		0
48 
49 int stm32_sdram_init(struct udevice *dev)
50 {
51 	struct stm32_sdram_params *params = dev_get_platdata(dev);
52 
53 	writel(params->sdram_control.sdclk << FMC_SDCR_SDCLK_SHIFT
54 		| params->sdram_control.cas_latency << FMC_SDCR_CAS_SHIFT
55 		| params->sdram_control.no_banks << FMC_SDCR_NB_SHIFT
56 		| params->sdram_control.memory_width << FMC_SDCR_MWID_SHIFT
57 		| params->sdram_control.no_rows << FMC_SDCR_NR_SHIFT
58 		| params->sdram_control.no_columns << FMC_SDCR_NC_SHIFT
59 		| params->sdram_control.rd_pipe_delay << FMC_SDCR_RPIPE_SHIFT
60 		| params->sdram_control.rd_burst << FMC_SDCR_RBURST_SHIFT,
61 		&STM32_SDRAM_FMC->sdcr1);
62 
63 	writel(params->sdram_timing.trcd << FMC_SDTR_TRCD_SHIFT
64 		| params->sdram_timing.trp << FMC_SDTR_TRP_SHIFT
65 		| params->sdram_timing.twr << FMC_SDTR_TWR_SHIFT
66 		| params->sdram_timing.trc << FMC_SDTR_TRC_SHIFT
67 		| params->sdram_timing.tras << FMC_SDTR_TRAS_SHIFT
68 		| params->sdram_timing.txsr << FMC_SDTR_TXSR_SHIFT
69 		| params->sdram_timing.tmrd << FMC_SDTR_TMRD_SHIFT,
70 		&STM32_SDRAM_FMC->sdtr1);
71 
72 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK,
73 	       &STM32_SDRAM_FMC->sdcmr);
74 	udelay(200);	/* 200 us delay, page 10, "Power-Up" */
75 	FMC_BUSY_WAIT();
76 
77 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE,
78 	       &STM32_SDRAM_FMC->sdcmr);
79 	udelay(100);
80 	FMC_BUSY_WAIT();
81 
82 	writel((FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_AUTOREFRESH
83 		| 7 << FMC_SDCMR_NRFS_SHIFT), &STM32_SDRAM_FMC->sdcmr);
84 	udelay(100);
85 	FMC_BUSY_WAIT();
86 
87 	writel(FMC_SDCMR_BANK_1 | (SDRAM_MODE_BL << SDRAM_MODE_BL_SHIFT
88 	       | params->sdram_control.cas_latency << SDRAM_MODE_CAS_SHIFT)
89 	       << FMC_SDCMR_MODE_REGISTER_SHIFT | FMC_SDCMR_MODE_WRITE_MODE,
90 	       &STM32_SDRAM_FMC->sdcmr);
91 	udelay(100);
92 	FMC_BUSY_WAIT();
93 
94 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL,
95 	       &STM32_SDRAM_FMC->sdcmr);
96 	FMC_BUSY_WAIT();
97 
98 	/* Refresh timer */
99 	writel((params->sdram_ref_count) << 1, &STM32_SDRAM_FMC->sdrtr);
100 
101 	return 0;
102 }
103 
104 static int stm32_fmc_ofdata_to_platdata(struct udevice *dev)
105 {
106 	int ret;
107 	int node = dev->of_offset;
108 	const void *blob = gd->fdt_blob;
109 	struct stm32_sdram_params *params = dev_get_platdata(dev);
110 
111 	params->no_sdram_banks = fdtdec_get_uint(blob, node, "mr-nbanks", 1);
112 	debug("%s, no of banks = %d\n", __func__, params->no_sdram_banks);
113 
114 	fdt_for_each_subnode(node, blob, node) {
115 		ret = fdtdec_get_byte_array(blob, node, "st,sdram-control",
116 					    (u8 *)&params->sdram_control,
117 					    sizeof(params->sdram_control));
118 		if (ret)
119 			return ret;
120 		ret = fdtdec_get_byte_array(blob, node, "st,sdram-timing",
121 					    (u8 *)&params->sdram_timing,
122 					    sizeof(params->sdram_timing));
123 		if (ret)
124 			return ret;
125 
126 		params->sdram_ref_count = fdtdec_get_int(blob, node,
127 						"st,sdram-refcount", 8196);
128 	}
129 
130 	return 0;
131 }
132 
133 static int stm32_fmc_probe(struct udevice *dev)
134 {
135 #ifdef CONFIG_CLK
136 	int ret;
137 	struct clk clk;
138 
139 	ret = clk_get_by_index(dev, 0, &clk);
140 	if (ret < 0)
141 		return ret;
142 
143 	ret = clk_enable(&clk);
144 
145 	if (ret) {
146 		dev_err(dev, "failed to enable clock\n");
147 		return ret;
148 	}
149 #endif
150 	ret = stm32_sdram_init(dev);
151 	if (ret)
152 		return ret;
153 
154 	return 0;
155 }
156 
157 static int stm32_fmc_get_info(struct udevice *dev, struct ram_info *info)
158 {
159 	return 0;
160 }
161 
162 static struct ram_ops stm32_fmc_ops = {
163 	.get_info = stm32_fmc_get_info,
164 };
165 
166 static const struct udevice_id stm32_fmc_ids[] = {
167 	{ .compatible = "st,stm32-fmc" },
168 	{ }
169 };
170 
171 U_BOOT_DRIVER(stm32_fmc) = {
172 	.name = "stm32_fmc",
173 	.id = UCLASS_RAM,
174 	.of_match = stm32_fmc_ids,
175 	.ops = &stm32_fmc_ops,
176 	.ofdata_to_platdata = stm32_fmc_ofdata_to_platdata,
177 	.probe = stm32_fmc_probe,
178 	.platdata_auto_alloc_size = sizeof(struct stm32_sdram_params),
179 };
180