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1/*
2 * Author: Daniel Thompson <daniel.thompson@linaro.org>
3 *
4 * Inspired by clk-asm9260.c .
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/clk-provider.h>
20#include <linux/err.h>
21#include <linux/io.h>
22#include <linux/slab.h>
23#include <linux/spinlock.h>
24#include <linux/of.h>
25#include <linux/of_address.h>
26
27#define STM32F4_RCC_PLLCFGR 0x04
28#define STM32F4_RCC_CFGR 0x08
29#define STM32F4_RCC_AHB1ENR 0x30
30#define STM32F4_RCC_AHB2ENR 0x34
31#define STM32F4_RCC_AHB3ENR 0x38
32#define STM32F4_RCC_APB1ENR 0x40
33#define STM32F4_RCC_APB2ENR 0x44
34
35struct stm32f4_gate_data {
36 u8 offset;
37 u8 bit_idx;
38 const char *name;
39 const char *parent_name;
40 unsigned long flags;
41};
42
43static const struct stm32f4_gate_data stm32f4_gates[] __initconst = {
44 { STM32F4_RCC_AHB1ENR, 0, "gpioa", "ahb_div" },
45 { STM32F4_RCC_AHB1ENR, 1, "gpiob", "ahb_div" },
46 { STM32F4_RCC_AHB1ENR, 2, "gpioc", "ahb_div" },
47 { STM32F4_RCC_AHB1ENR, 3, "gpiod", "ahb_div" },
48 { STM32F4_RCC_AHB1ENR, 4, "gpioe", "ahb_div" },
49 { STM32F4_RCC_AHB1ENR, 5, "gpiof", "ahb_div" },
50 { STM32F4_RCC_AHB1ENR, 6, "gpiog", "ahb_div" },
51 { STM32F4_RCC_AHB1ENR, 7, "gpioh", "ahb_div" },
52 { STM32F4_RCC_AHB1ENR, 8, "gpioi", "ahb_div" },
53 { STM32F4_RCC_AHB1ENR, 9, "gpioj", "ahb_div" },
54 { STM32F4_RCC_AHB1ENR, 10, "gpiok", "ahb_div" },
55 { STM32F4_RCC_AHB1ENR, 12, "crc", "ahb_div" },
56 { STM32F4_RCC_AHB1ENR, 18, "bkpsra", "ahb_div" },
57 { STM32F4_RCC_AHB1ENR, 20, "ccmdatam", "ahb_div" },
58 { STM32F4_RCC_AHB1ENR, 21, "dma1", "ahb_div" },
59 { STM32F4_RCC_AHB1ENR, 22, "dma2", "ahb_div" },
60 { STM32F4_RCC_AHB1ENR, 23, "dma2d", "ahb_div" },
61 { STM32F4_RCC_AHB1ENR, 25, "ethmac", "ahb_div" },
62 { STM32F4_RCC_AHB1ENR, 26, "ethmactx", "ahb_div" },
63 { STM32F4_RCC_AHB1ENR, 27, "ethmacrx", "ahb_div" },
64 { STM32F4_RCC_AHB1ENR, 28, "ethmacptp", "ahb_div" },
65 { STM32F4_RCC_AHB1ENR, 29, "otghs", "ahb_div" },
66 { STM32F4_RCC_AHB1ENR, 30, "otghsulpi", "ahb_div" },
67
68 { STM32F4_RCC_AHB2ENR, 0, "dcmi", "ahb_div" },
69 { STM32F4_RCC_AHB2ENR, 4, "cryp", "ahb_div" },
70 { STM32F4_RCC_AHB2ENR, 5, "hash", "ahb_div" },
71 { STM32F4_RCC_AHB2ENR, 6, "rng", "pll48" },
72 { STM32F4_RCC_AHB2ENR, 7, "otgfs", "pll48" },
73
74 { STM32F4_RCC_AHB3ENR, 0, "fmc", "ahb_div",
75 CLK_IGNORE_UNUSED },
76
77 { STM32F4_RCC_APB1ENR, 0, "tim2", "apb1_mul" },
78 { STM32F4_RCC_APB1ENR, 1, "tim3", "apb1_mul" },
79 { STM32F4_RCC_APB1ENR, 2, "tim4", "apb1_mul" },
80 { STM32F4_RCC_APB1ENR, 3, "tim5", "apb1_mul" },
81 { STM32F4_RCC_APB1ENR, 4, "tim6", "apb1_mul" },
82 { STM32F4_RCC_APB1ENR, 5, "tim7", "apb1_mul" },
83 { STM32F4_RCC_APB1ENR, 6, "tim12", "apb1_mul" },
84 { STM32F4_RCC_APB1ENR, 7, "tim13", "apb1_mul" },
85 { STM32F4_RCC_APB1ENR, 8, "tim14", "apb1_mul" },
86 { STM32F4_RCC_APB1ENR, 11, "wwdg", "apb1_div" },
87 { STM32F4_RCC_APB1ENR, 14, "spi2", "apb1_div" },
88 { STM32F4_RCC_APB1ENR, 15, "spi3", "apb1_div" },
89 { STM32F4_RCC_APB1ENR, 17, "uart2", "apb1_div" },
90 { STM32F4_RCC_APB1ENR, 18, "uart3", "apb1_div" },
91 { STM32F4_RCC_APB1ENR, 19, "uart4", "apb1_div" },
92 { STM32F4_RCC_APB1ENR, 20, "uart5", "apb1_div" },
93 { STM32F4_RCC_APB1ENR, 21, "i2c1", "apb1_div" },
94 { STM32F4_RCC_APB1ENR, 22, "i2c2", "apb1_div" },
95 { STM32F4_RCC_APB1ENR, 23, "i2c3", "apb1_div" },
96 { STM32F4_RCC_APB1ENR, 25, "can1", "apb1_div" },
97 { STM32F4_RCC_APB1ENR, 26, "can2", "apb1_div" },
98 { STM32F4_RCC_APB1ENR, 28, "pwr", "apb1_div" },
99 { STM32F4_RCC_APB1ENR, 29, "dac", "apb1_div" },
100 { STM32F4_RCC_APB1ENR, 30, "uart7", "apb1_div" },
101 { STM32F4_RCC_APB1ENR, 31, "uart8", "apb1_div" },
102
103 { STM32F4_RCC_APB2ENR, 0, "tim1", "apb2_mul" },
104 { STM32F4_RCC_APB2ENR, 1, "tim8", "apb2_mul" },
105 { STM32F4_RCC_APB2ENR, 4, "usart1", "apb2_div" },
106 { STM32F4_RCC_APB2ENR, 5, "usart6", "apb2_div" },
107 { STM32F4_RCC_APB2ENR, 8, "adc1", "apb2_div" },
108 { STM32F4_RCC_APB2ENR, 9, "adc2", "apb2_div" },
109 { STM32F4_RCC_APB2ENR, 10, "adc3", "apb2_div" },
110 { STM32F4_RCC_APB2ENR, 11, "sdio", "pll48" },
111 { STM32F4_RCC_APB2ENR, 12, "spi1", "apb2_div" },
112 { STM32F4_RCC_APB2ENR, 13, "spi4", "apb2_div" },
113 { STM32F4_RCC_APB2ENR, 14, "syscfg", "apb2_div" },
114 { STM32F4_RCC_APB2ENR, 16, "tim9", "apb2_mul" },
115 { STM32F4_RCC_APB2ENR, 17, "tim10", "apb2_mul" },
116 { STM32F4_RCC_APB2ENR, 18, "tim11", "apb2_mul" },
117 { STM32F4_RCC_APB2ENR, 20, "spi5", "apb2_div" },
118 { STM32F4_RCC_APB2ENR, 21, "spi6", "apb2_div" },
119 { STM32F4_RCC_APB2ENR, 22, "sai1", "apb2_div" },
120 { STM32F4_RCC_APB2ENR, 26, "ltdc", "apb2_div" },
121};
122
123/*
124 * MAX_CLKS is the maximum value in the enumeration below plus the combined
125 * hweight of stm32f42xx_gate_map (plus one).
126 */
127#define MAX_CLKS 74
128
129enum { SYSTICK, FCLK };
130
131/*
132 * This bitmask tells us which bit offsets (0..192) on STM32F4[23]xxx
133 * have gate bits associated with them. Its combined hweight is 71.
134 */
135static const u64 stm32f42xx_gate_map[] = { 0x000000f17ef417ffull,
136 0x0000000000000001ull,
137 0x04777f33f6fec9ffull };
138
139static struct clk *clks[MAX_CLKS];
140static DEFINE_SPINLOCK(stm32f4_clk_lock);
141static void __iomem *base;
142
143/*
144 * "Multiplier" device for APBx clocks.
145 *
146 * The APBx dividers are power-of-two dividers and, if *not* running in 1:1
147 * mode, they also tap out the one of the low order state bits to run the
148 * timers. ST datasheets represent this feature as a (conditional) clock
149 * multiplier.
150 */
151struct clk_apb_mul {
152 struct clk_hw hw;
153 u8 bit_idx;
154};
155
156#define to_clk_apb_mul(_hw) container_of(_hw, struct clk_apb_mul, hw)
157
158static unsigned long clk_apb_mul_recalc_rate(struct clk_hw *hw,
159 unsigned long parent_rate)
160{
161 struct clk_apb_mul *am = to_clk_apb_mul(hw);
162
163 if (readl(base + STM32F4_RCC_CFGR) & BIT(am->bit_idx))
164 return parent_rate * 2;
165
166 return parent_rate;
167}
168
169static long clk_apb_mul_round_rate(struct clk_hw *hw, unsigned long rate,
170 unsigned long *prate)
171{
172 struct clk_apb_mul *am = to_clk_apb_mul(hw);
173 unsigned long mult = 1;
174
175 if (readl(base + STM32F4_RCC_CFGR) & BIT(am->bit_idx))
176 mult = 2;
177
178 if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
179 unsigned long best_parent = rate / mult;
180
181 *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
182 }
183
184 return *prate * mult;
185}
186
187static int clk_apb_mul_set_rate(struct clk_hw *hw, unsigned long rate,
188 unsigned long parent_rate)
189{
190 /*
191 * We must report success but we can do so unconditionally because
192 * clk_apb_mul_round_rate returns values that ensure this call is a
193 * nop.
194 */
195
196 return 0;
197}
198
199static const struct clk_ops clk_apb_mul_factor_ops = {
200 .round_rate = clk_apb_mul_round_rate,
201 .set_rate = clk_apb_mul_set_rate,
202 .recalc_rate = clk_apb_mul_recalc_rate,
203};
204
205static struct clk *clk_register_apb_mul(struct device *dev, const char *name,
206 const char *parent_name,
207 unsigned long flags, u8 bit_idx)
208{
209 struct clk_apb_mul *am;
210 struct clk_init_data init;
211 struct clk *clk;
212
213 am = kzalloc(sizeof(*am), GFP_KERNEL);
214 if (!am)
215 return ERR_PTR(-ENOMEM);
216
217 am->bit_idx = bit_idx;
218 am->hw.init = &init;
219
220 init.name = name;
221 init.ops = &clk_apb_mul_factor_ops;
222 init.flags = flags;
223 init.parent_names = &parent_name;
224 init.num_parents = 1;
225
226 clk = clk_register(dev, &am->hw);
227
228 if (IS_ERR(clk))
229 kfree(am);
230
231 return clk;
232}
233
234/*
235 * Decode current PLL state and (statically) model the state we inherit from
236 * the bootloader.
237 */
238static void stm32f4_rcc_register_pll(const char *hse_clk, const char *hsi_clk)
239{
240 unsigned long pllcfgr = readl(base + STM32F4_RCC_PLLCFGR);
241
242 unsigned long pllm = pllcfgr & 0x3f;
243 unsigned long plln = (pllcfgr >> 6) & 0x1ff;
244 unsigned long pllp = BIT(((pllcfgr >> 16) & 3) + 1);
245 const char *pllsrc = pllcfgr & BIT(22) ? hse_clk : hsi_clk;
246 unsigned long pllq = (pllcfgr >> 24) & 0xf;
247
248 clk_register_fixed_factor(NULL, "vco", pllsrc, 0, plln, pllm);
249 clk_register_fixed_factor(NULL, "pll", "vco", 0, 1, pllp);
250 clk_register_fixed_factor(NULL, "pll48", "vco", 0, 1, pllq);
251}
252
253/*
254 * Converts the primary and secondary indices (as they appear in DT) to an
255 * offset into our struct clock array.
256 */
257static int stm32f4_rcc_lookup_clk_idx(u8 primary, u8 secondary)
258{
259 u64 table[ARRAY_SIZE(stm32f42xx_gate_map)];
260
261 if (primary == 1) {
262 if (WARN_ON(secondary > FCLK))
263 return -EINVAL;
264 return secondary;
265 }
266
267 memcpy(table, stm32f42xx_gate_map, sizeof(table));
268
269 /* only bits set in table can be used as indices */
270 if (WARN_ON(secondary >= BITS_PER_BYTE * sizeof(table) ||
271 0 == (table[BIT_ULL_WORD(secondary)] &
272 BIT_ULL_MASK(secondary))))
273 return -EINVAL;
274
275 /* mask out bits above our current index */
276 table[BIT_ULL_WORD(secondary)] &=
277 GENMASK_ULL(secondary % BITS_PER_LONG_LONG, 0);
278
279 return FCLK + hweight64(table[0]) +
280 (BIT_ULL_WORD(secondary) >= 1 ? hweight64(table[1]) : 0) +
281 (BIT_ULL_WORD(secondary) >= 2 ? hweight64(table[2]) : 0);
282}
283
284static struct clk *
285stm32f4_rcc_lookup_clk(struct of_phandle_args *clkspec, void *data)
286{
287 int i = stm32f4_rcc_lookup_clk_idx(clkspec->args[0], clkspec->args[1]);
288
289 if (i < 0)
290 return ERR_PTR(-EINVAL);
291
292 return clks[i];
293}
294
295static const char *sys_parents[] __initdata = { "hsi", NULL, "pll" };
296
297static const struct clk_div_table ahb_div_table[] = {
298 { 0x0, 1 }, { 0x1, 1 }, { 0x2, 1 }, { 0x3, 1 },
299 { 0x4, 1 }, { 0x5, 1 }, { 0x6, 1 }, { 0x7, 1 },
300 { 0x8, 2 }, { 0x9, 4 }, { 0xa, 8 }, { 0xb, 16 },
301 { 0xc, 64 }, { 0xd, 128 }, { 0xe, 256 }, { 0xf, 512 },
302 { 0 },
303};
304
305static const struct clk_div_table apb_div_table[] = {
306 { 0, 1 }, { 0, 1 }, { 0, 1 }, { 0, 1 },
307 { 4, 2 }, { 5, 4 }, { 6, 8 }, { 7, 16 },
308 { 0 },
309};
310
311static void __init stm32f4_rcc_init(struct device_node *np)
312{
313 const char *hse_clk;
314 int n;
315
316 base = of_iomap(np, 0);
317 if (!base) {
318 pr_err("%s: unable to map resource", np->name);
319 return;
320 }
321
322 hse_clk = of_clk_get_parent_name(np, 0);
323
324 clk_register_fixed_rate_with_accuracy(NULL, "hsi", NULL, 0,
325 16000000, 160000);
326 stm32f4_rcc_register_pll(hse_clk, "hsi");
327
328 sys_parents[1] = hse_clk;
329 clk_register_mux_table(
330 NULL, "sys", sys_parents, ARRAY_SIZE(sys_parents), 0,
331 base + STM32F4_RCC_CFGR, 0, 3, 0, NULL, &stm32f4_clk_lock);
332
333 clk_register_divider_table(NULL, "ahb_div", "sys",
334 CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR,
335 4, 4, 0, ahb_div_table, &stm32f4_clk_lock);
336
337 clk_register_divider_table(NULL, "apb1_div", "ahb_div",
338 CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR,
339 10, 3, 0, apb_div_table, &stm32f4_clk_lock);
340 clk_register_apb_mul(NULL, "apb1_mul", "apb1_div",
341 CLK_SET_RATE_PARENT, 12);
342
343 clk_register_divider_table(NULL, "apb2_div", "ahb_div",
344 CLK_SET_RATE_PARENT, base + STM32F4_RCC_CFGR,
345 13, 3, 0, apb_div_table, &stm32f4_clk_lock);
346 clk_register_apb_mul(NULL, "apb2_mul", "apb2_div",
347 CLK_SET_RATE_PARENT, 15);
348
349 clks[SYSTICK] = clk_register_fixed_factor(NULL, "systick", "ahb_div",
350 0, 1, 8);
351 clks[FCLK] = clk_register_fixed_factor(NULL, "fclk", "ahb_div",
352 0, 1, 1);
353
354 for (n = 0; n < ARRAY_SIZE(stm32f4_gates); n++) {
355 const struct stm32f4_gate_data *gd = &stm32f4_gates[n];
356 unsigned int secondary =
357 8 * (gd->offset - STM32F4_RCC_AHB1ENR) + gd->bit_idx;
358 int idx = stm32f4_rcc_lookup_clk_idx(0, secondary);
359
360 if (idx < 0)
361 goto fail;
362
363 clks[idx] = clk_register_gate(
364 NULL, gd->name, gd->parent_name, gd->flags,
365 base + gd->offset, gd->bit_idx, 0, &stm32f4_clk_lock);
366
367 if (IS_ERR(clks[n])) {
368 pr_err("%s: Unable to register leaf clock %s\n",
369 np->full_name, gd->name);
370 goto fail;
371 }
372 }
373
374 of_clk_add_provider(np, stm32f4_rcc_lookup_clk, NULL);
375 return;
376fail:
377 iounmap(base);
378}
379CLK_OF_DECLARE(stm32f4_rcc, "st,stm32f42xx-rcc", stm32f4_rcc_init);