xref: /openbmc/u-boot/drivers/ram/stm32_sdram.c (revision 774171020beaf3af19dcc8056c9de38653bc121b)
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 rd_burst;
25 	u8 rd_pipe_delay;
26 };
27 
28 struct stm32_sdram_timing {
29 	u8 tmrd;
30 	u8 txsr;
31 	u8 tras;
32 	u8 trc;
33 	u8 trp;
34 	u8 trcd;
35 };
36 struct stm32_sdram_params {
37 	u8 no_sdram_banks;
38 	struct stm32_sdram_control sdram_control;
39 	struct stm32_sdram_timing sdram_timing;
40 };
41 static inline u32 _ns2clk(u32 ns, u32 freq)
42 {
43 	u32 tmp = freq/1000000;
44 	return (tmp * ns) / 1000;
45 }
46 
47 #define NS2CLK(ns) (_ns2clk(ns, freq))
48 
49 #define SDRAM_TREF	(NS2CLK(64000000 / 8192) - 20)
50 
51 #define SDRAM_MODE_BL_SHIFT	0
52 #define SDRAM_MODE_CAS_SHIFT	4
53 #define SDRAM_MODE_BL		0
54 #define SDRAM_MODE_CAS		3
55 
56 #define SDRAM_TRDL	12
57 
58 int stm32_sdram_init(struct udevice *dev)
59 {
60 	u32 freq;
61 	u32 sdram_twr;
62 	struct stm32_sdram_params *params = dev_get_platdata(dev);
63 
64 	/*
65 	 * Get frequency for NS2CLK calculation.
66 	 */
67 	freq = clock_get(CLOCK_AHB) / CONFIG_SYS_RAM_FREQ_DIV;
68 	debug("%s, sdram freq = %d\n", __func__, freq);
69 
70 	/* Last data in to row precharge, need also comply ineq on page 1648 */
71 	sdram_twr = max(
72 			max(SDRAM_TRDL, params->sdram_timing.tras
73 			    - params->sdram_timing.trcd),
74 			params->sdram_timing.trc - params->sdram_timing.trcd
75 			- params->sdram_timing.trp
76 		       );
77 
78 	writel(CONFIG_SYS_RAM_FREQ_DIV << FMC_SDCR_SDCLK_SHIFT
79 		| params->sdram_control.cas_latency << FMC_SDCR_CAS_SHIFT
80 		| params->sdram_control.no_banks << FMC_SDCR_NB_SHIFT
81 		| params->sdram_control.memory_width << FMC_SDCR_MWID_SHIFT
82 		| params->sdram_control.no_rows << FMC_SDCR_NR_SHIFT
83 		| params->sdram_control.no_columns << FMC_SDCR_NC_SHIFT
84 		| params->sdram_control.rd_pipe_delay << FMC_SDCR_RPIPE_SHIFT
85 		| params->sdram_control.rd_burst << FMC_SDCR_RBURST_SHIFT,
86 		&STM32_SDRAM_FMC->sdcr1);
87 
88 	writel(NS2CLK(params->sdram_timing.trcd) << FMC_SDTR_TRCD_SHIFT
89 		| NS2CLK(params->sdram_timing.trp) << FMC_SDTR_TRP_SHIFT
90 		| NS2CLK(sdram_twr) << FMC_SDTR_TWR_SHIFT
91 		| NS2CLK(params->sdram_timing.trc) << FMC_SDTR_TRC_SHIFT
92 		| NS2CLK(params->sdram_timing.tras) << FMC_SDTR_TRAS_SHIFT
93 		| NS2CLK(params->sdram_timing.txsr) << FMC_SDTR_TXSR_SHIFT
94 		| NS2CLK(params->sdram_timing.tmrd) << FMC_SDTR_TMRD_SHIFT,
95 		&STM32_SDRAM_FMC->sdtr1);
96 
97 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_START_CLOCK,
98 	       &STM32_SDRAM_FMC->sdcmr);
99 	udelay(200);	/* 200 us delay, page 10, "Power-Up" */
100 	FMC_BUSY_WAIT();
101 
102 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_PRECHARGE,
103 	       &STM32_SDRAM_FMC->sdcmr);
104 	udelay(100);
105 	FMC_BUSY_WAIT();
106 
107 	writel((FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_AUTOREFRESH
108 		| 7 << FMC_SDCMR_NRFS_SHIFT), &STM32_SDRAM_FMC->sdcmr);
109 	udelay(100);
110 	FMC_BUSY_WAIT();
111 
112 	writel(FMC_SDCMR_BANK_1 | (SDRAM_MODE_BL << SDRAM_MODE_BL_SHIFT
113 	       | SDRAM_MODE_CAS << SDRAM_MODE_CAS_SHIFT)
114 	       << FMC_SDCMR_MODE_REGISTER_SHIFT | FMC_SDCMR_MODE_WRITE_MODE,
115 	       &STM32_SDRAM_FMC->sdcmr);
116 	udelay(100);
117 	FMC_BUSY_WAIT();
118 
119 	writel(FMC_SDCMR_BANK_1 | FMC_SDCMR_MODE_NORMAL,
120 	       &STM32_SDRAM_FMC->sdcmr);
121 	FMC_BUSY_WAIT();
122 
123 	/* Refresh timer */
124 	writel(SDRAM_TREF, &STM32_SDRAM_FMC->sdrtr);
125 
126 	return 0;
127 }
128 
129 static int stm32_fmc_ofdata_to_platdata(struct udevice *dev)
130 {
131 	int ret;
132 	int node = dev->of_offset;
133 	const void *blob = gd->fdt_blob;
134 	struct stm32_sdram_params *params = dev_get_platdata(dev);
135 
136 	params->no_sdram_banks = fdtdec_get_uint(blob, node, "mr-nbanks", 1);
137 	debug("%s, no of banks = %d\n", __func__, params->no_sdram_banks);
138 
139 	fdt_for_each_subnode(node, blob, node) {
140 		ret = fdtdec_get_byte_array(blob, node, "st,sdram-control",
141 					    (u8 *)&params->sdram_control,
142 					    sizeof(params->sdram_control));
143 		if (ret)
144 			return ret;
145 
146 		ret = fdtdec_get_byte_array(blob, node, "st,sdram-timing",
147 					    (u8 *)&params->sdram_timing,
148 					    sizeof(params->sdram_timing));
149 		if (ret)
150 			return ret;
151 	}
152 
153 	return 0;
154 }
155 
156 static int stm32_fmc_probe(struct udevice *dev)
157 {
158 #ifdef CONFIG_CLK
159 	int ret;
160 	struct clk clk;
161 
162 	ret = clk_get_by_index(dev, 0, &clk);
163 	if (ret < 0)
164 		return ret;
165 
166 	ret = clk_enable(&clk);
167 
168 	if (ret) {
169 		dev_err(dev, "failed to enable clock\n");
170 		return ret;
171 	}
172 #endif
173 	ret = stm32_sdram_init(dev);
174 	if (ret)
175 		return ret;
176 
177 	return 0;
178 }
179 
180 static int stm32_fmc_get_info(struct udevice *dev, struct ram_info *info)
181 {
182 	info->size = CONFIG_SYS_RAM_SIZE;
183 	return 0;
184 }
185 
186 static struct ram_ops stm32_fmc_ops = {
187 	.get_info = stm32_fmc_get_info,
188 };
189 
190 static const struct udevice_id stm32_fmc_ids[] = {
191 	{ .compatible = "st,stm32-fmc" },
192 	{ }
193 };
194 
195 U_BOOT_DRIVER(stm32_fmc) = {
196 	.name = "stm32_fmc",
197 	.id = UCLASS_RAM,
198 	.of_match = stm32_fmc_ids,
199 	.ops = &stm32_fmc_ops,
200 	.ofdata_to_platdata = stm32_fmc_ofdata_to_platdata,
201 	.probe = stm32_fmc_probe,
202 	.platdata_auto_alloc_size = sizeof(struct stm32_sdram_params),
203 };
204