1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Cortina Gemini SoC Clock Controller driver
4 * Copyright (c) 2017 Linus Walleij <linus.walleij@linaro.org>
5 */
6
7#define pr_fmt(fmt) "clk-gemini: " fmt
8
9#include <linux/init.h>
10#include <linux/module.h>
11#include <linux/platform_device.h>
12#include <linux/slab.h>
13#include <linux/err.h>
14#include <linux/io.h>
15#include <linux/clk-provider.h>
16#include <linux/of.h>
17#include <linux/of_address.h>
18#include <linux/mfd/syscon.h>
19#include <linux/regmap.h>
20#include <linux/spinlock.h>
21#include <linux/reset-controller.h>
22#include <dt-bindings/reset/cortina,gemini-reset.h>
23#include <dt-bindings/clock/cortina,gemini-clock.h>
24
25/* Globally visible clocks */
26static DEFINE_SPINLOCK(gemini_clk_lock);
27
28#define GEMINI_GLOBAL_STATUS 0x04
29#define PLL_OSC_SEL BIT(30)
30#define AHBSPEED_SHIFT (15)
31#define AHBSPEED_MASK 0x07
32#define CPU_AHB_RATIO_SHIFT (18)
33#define CPU_AHB_RATIO_MASK 0x03
34
35#define GEMINI_GLOBAL_PLL_CONTROL 0x08
36
37#define GEMINI_GLOBAL_SOFT_RESET 0x0c
38
39#define GEMINI_GLOBAL_MISC_CONTROL 0x30
40#define PCI_CLK_66MHZ BIT(18)
41
42#define GEMINI_GLOBAL_CLOCK_CONTROL 0x34
43#define PCI_CLKRUN_EN BIT(16)
44#define TVC_HALFDIV_SHIFT (24)
45#define TVC_HALFDIV_MASK 0x1f
46#define SECURITY_CLK_SEL BIT(29)
47
48#define GEMINI_GLOBAL_PCI_DLL_CONTROL 0x44
49#define PCI_DLL_BYPASS BIT(31)
50#define PCI_DLL_TAP_SEL_MASK 0x1f
51
52/**
53 * struct gemini_data_data - Gemini gated clocks
54 * @bit_idx: the bit used to gate this clock in the clock register
55 * @name: the clock name
56 * @parent_name: the name of the parent clock
57 * @flags: standard clock framework flags
58 */
59struct gemini_gate_data {
60 u8 bit_idx;
61 const char *name;
62 const char *parent_name;
63 unsigned long flags;
64};
65
66/**
67 * struct clk_gemini_pci - Gemini PCI clock
68 * @hw: corresponding clock hardware entry
69 * @map: regmap to access the registers
70 * @rate: current rate
71 */
72struct clk_gemini_pci {
73 struct clk_hw hw;
74 struct regmap *map;
75 unsigned long rate;
76};
77
78/**
79 * struct gemini_reset - gemini reset controller
80 * @map: regmap to access the containing system controller
81 * @rcdev: reset controller device
82 */
83struct gemini_reset {
84 struct regmap *map;
85 struct reset_controller_dev rcdev;
86};
87
88/* Keeps track of all clocks */
89static struct clk_hw_onecell_data *gemini_clk_data;
90
91static const struct gemini_gate_data gemini_gates[] = {
92 { 1, "security-gate", "secdiv", 0 },
93 { 2, "gmac0-gate", "ahb", 0 },
94 { 3, "gmac1-gate", "ahb", 0 },
95 { 4, "sata0-gate", "ahb", 0 },
96 { 5, "sata1-gate", "ahb", 0 },
97 { 6, "usb0-gate", "ahb", 0 },
98 { 7, "usb1-gate", "ahb", 0 },
99 { 8, "ide-gate", "ahb", 0 },
100 { 9, "pci-gate", "ahb", 0 },
101 /*
102 * The DDR controller may never have a driver, but certainly must
103 * not be gated off.
104 */
105 { 10, "ddr-gate", "ahb", CLK_IS_CRITICAL },
106 /*
107 * The flash controller must be on to access NOR flash through the
108 * memory map.
109 */
110 { 11, "flash-gate", "ahb", CLK_IGNORE_UNUSED },
111 { 12, "tvc-gate", "ahb", 0 },
112 { 13, "boot-gate", "apb", 0 },
113};
114
115#define to_pciclk(_hw) container_of(_hw, struct clk_gemini_pci, hw)
116
117#define to_gemini_reset(p) container_of((p), struct gemini_reset, rcdev)
118
119static unsigned long gemini_pci_recalc_rate(struct clk_hw *hw,
120 unsigned long parent_rate)
121{
122 struct clk_gemini_pci *pciclk = to_pciclk(hw);
123 u32 val;
124
125 regmap_read(pciclk->map, GEMINI_GLOBAL_MISC_CONTROL, &val);
126 if (val & PCI_CLK_66MHZ)
127 return 66000000;
128 return 33000000;
129}
130
131static long gemini_pci_round_rate(struct clk_hw *hw, unsigned long rate,
132 unsigned long *prate)
133{
134 /* We support 33 and 66 MHz */
135 if (rate < 48000000)
136 return 33000000;
137 return 66000000;
138}
139
140static int gemini_pci_set_rate(struct clk_hw *hw, unsigned long rate,
141 unsigned long parent_rate)
142{
143 struct clk_gemini_pci *pciclk = to_pciclk(hw);
144
145 if (rate == 33000000)
146 return regmap_update_bits(pciclk->map,
147 GEMINI_GLOBAL_MISC_CONTROL,
148 PCI_CLK_66MHZ, 0);
149 if (rate == 66000000)
150 return regmap_update_bits(pciclk->map,
151 GEMINI_GLOBAL_MISC_CONTROL,
152 0, PCI_CLK_66MHZ);
153 return -EINVAL;
154}
155
156static int gemini_pci_enable(struct clk_hw *hw)
157{
158 struct clk_gemini_pci *pciclk = to_pciclk(hw);
159
160 regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
161 0, PCI_CLKRUN_EN);
162 return 0;
163}
164
165static void gemini_pci_disable(struct clk_hw *hw)
166{
167 struct clk_gemini_pci *pciclk = to_pciclk(hw);
168
169 regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
170 PCI_CLKRUN_EN, 0);
171}
172
173static int gemini_pci_is_enabled(struct clk_hw *hw)
174{
175 struct clk_gemini_pci *pciclk = to_pciclk(hw);
176 unsigned int val;
177
178 regmap_read(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
179 return !!(val & PCI_CLKRUN_EN);
180}
181
182static const struct clk_ops gemini_pci_clk_ops = {
183 .recalc_rate = gemini_pci_recalc_rate,
184 .round_rate = gemini_pci_round_rate,
185 .set_rate = gemini_pci_set_rate,
186 .enable = gemini_pci_enable,
187 .disable = gemini_pci_disable,
188 .is_enabled = gemini_pci_is_enabled,
189};
190
191static struct clk_hw *gemini_pci_clk_setup(const char *name,
192 const char *parent_name,
193 struct regmap *map)
194{
195 struct clk_gemini_pci *pciclk;
196 struct clk_init_data init;
197 int ret;
198
199 pciclk = kzalloc(sizeof(*pciclk), GFP_KERNEL);
200 if (!pciclk)
201 return ERR_PTR(-ENOMEM);
202
203 init.name = name;
204 init.ops = &gemini_pci_clk_ops;
205 init.flags = 0;
206 init.parent_names = &parent_name;
207 init.num_parents = 1;
208 pciclk->map = map;
209 pciclk->hw.init = &init;
210
211 ret = clk_hw_register(NULL, &pciclk->hw);
212 if (ret) {
213 kfree(pciclk);
214 return ERR_PTR(ret);
215 }
216
217 return &pciclk->hw;
218}
219
220/*
221 * This is a self-deasserting reset controller.
222 */
223static int gemini_reset(struct reset_controller_dev *rcdev,
224 unsigned long id)
225{
226 struct gemini_reset *gr = to_gemini_reset(rcdev);
227
228 /* Manual says to always set BIT 30 (CPU1) to 1 */
229 return regmap_write(gr->map,
230 GEMINI_GLOBAL_SOFT_RESET,
231 BIT(GEMINI_RESET_CPU1) | BIT(id));
232}
233
234static int gemini_reset_assert(struct reset_controller_dev *rcdev,
235 unsigned long id)
236{
237 return 0;
238}
239
240static int gemini_reset_deassert(struct reset_controller_dev *rcdev,
241 unsigned long id)
242{
243 return 0;
244}
245
246static int gemini_reset_status(struct reset_controller_dev *rcdev,
247 unsigned long id)
248{
249 struct gemini_reset *gr = to_gemini_reset(rcdev);
250 u32 val;
251 int ret;
252
253 ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val);
254 if (ret)
255 return ret;
256
257 return !!(val & BIT(id));
258}
259
260static const struct reset_control_ops gemini_reset_ops = {
261 .reset = gemini_reset,
262 .assert = gemini_reset_assert,
263 .deassert = gemini_reset_deassert,
264 .status = gemini_reset_status,
265};
266
267static int gemini_clk_probe(struct platform_device *pdev)
268{
269 /* Gives the fracions 1x, 1.5x, 1.85x and 2x */
270 unsigned int cpu_ahb_mult[4] = { 1, 3, 24, 2 };
271 unsigned int cpu_ahb_div[4] = { 1, 2, 13, 1 };
272 void __iomem *base;
273 struct gemini_reset *gr;
274 struct regmap *map;
275 struct clk_hw *hw;
276 struct device *dev = &pdev->dev;
277 struct device_node *np = dev->of_node;
278 unsigned int mult, div;
279 struct resource *res;
280 u32 val;
281 int ret;
282 int i;
283
284 gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL);
285 if (!gr)
286 return -ENOMEM;
287
288 /* Remap the system controller for the exclusive register */
289 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
290 base = devm_ioremap_resource(dev, res);
291 if (IS_ERR(base))
292 return PTR_ERR(base);
293
294 map = syscon_node_to_regmap(np);
295 if (IS_ERR(map)) {
296 dev_err(dev, "no syscon regmap\n");
297 return PTR_ERR(map);
298 }
299
300 gr->map = map;
301 gr->rcdev.owner = THIS_MODULE;
302 gr->rcdev.nr_resets = 32;
303 gr->rcdev.ops = &gemini_reset_ops;
304 gr->rcdev.of_node = np;
305
306 ret = devm_reset_controller_register(dev, &gr->rcdev);
307 if (ret) {
308 dev_err(dev, "could not register reset controller\n");
309 return ret;
310 }
311
312 /* RTC clock 32768 Hz */
313 hw = clk_hw_register_fixed_rate(NULL, "rtc", NULL, 0, 32768);
314 gemini_clk_data->hws[GEMINI_CLK_RTC] = hw;
315
316 /* CPU clock derived as a fixed ratio from the AHB clock */
317 regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
318 val >>= CPU_AHB_RATIO_SHIFT;
319 val &= CPU_AHB_RATIO_MASK;
320 hw = clk_hw_register_fixed_factor(NULL, "cpu", "ahb", 0,
321 cpu_ahb_mult[val],
322 cpu_ahb_div[val]);
323 gemini_clk_data->hws[GEMINI_CLK_CPU] = hw;
324
325 /* Security clock is 1:1 or 0.75 of APB */
326 regmap_read(map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
327 if (val & SECURITY_CLK_SEL) {
328 mult = 1;
329 div = 1;
330 } else {
331 mult = 3;
332 div = 4;
333 }
334 hw = clk_hw_register_fixed_factor(NULL, "secdiv", "ahb", 0, mult, div);
335
336 /*
337 * These are the leaf gates, at boot no clocks are gated.
338 */
339 for (i = 0; i < ARRAY_SIZE(gemini_gates); i++) {
340 const struct gemini_gate_data *gd;
341
342 gd = &gemini_gates[i];
343 gemini_clk_data->hws[GEMINI_CLK_GATES + i] =
344 clk_hw_register_gate(NULL, gd->name,
345 gd->parent_name,
346 gd->flags,
347 base + GEMINI_GLOBAL_CLOCK_CONTROL,
348 gd->bit_idx,
349 CLK_GATE_SET_TO_DISABLE,
350 &gemini_clk_lock);
351 }
352
353 /*
354 * The TV Interface Controller has a 5-bit half divider register.
355 * This clock is supposed to be 27MHz as this is an exact multiple
356 * of PAL and NTSC frequencies. The register is undocumented :(
357 * FIXME: figure out the parent and how the divider works.
358 */
359 mult = 1;
360 div = ((val >> TVC_HALFDIV_SHIFT) & TVC_HALFDIV_MASK);
361 dev_dbg(dev, "TVC half divider value = %d\n", div);
362 div += 1;
363 hw = clk_hw_register_fixed_rate(NULL, "tvcdiv", "xtal", 0, 27000000);
364 gemini_clk_data->hws[GEMINI_CLK_TVC] = hw;
365
366 /* FIXME: very unclear what the parent is */
367 hw = gemini_pci_clk_setup("PCI", "xtal", map);
368 gemini_clk_data->hws[GEMINI_CLK_PCI] = hw;
369
370 /* FIXME: very unclear what the parent is */
371 hw = clk_hw_register_fixed_rate(NULL, "uart", "xtal", 0, 48000000);
372 gemini_clk_data->hws[GEMINI_CLK_UART] = hw;
373
374 return 0;
375}
376
377static const struct of_device_id gemini_clk_dt_ids[] = {
378 { .compatible = "cortina,gemini-syscon", },
379 { /* sentinel */ },
380};
381
382static struct platform_driver gemini_clk_driver = {
383 .probe = gemini_clk_probe,
384 .driver = {
385 .name = "gemini-clk",
386 .of_match_table = gemini_clk_dt_ids,
387 .suppress_bind_attrs = true,
388 },
389};
390builtin_platform_driver(gemini_clk_driver);
391
392static void __init gemini_cc_init(struct device_node *np)
393{
394 struct regmap *map;
395 struct clk_hw *hw;
396 unsigned long freq;
397 unsigned int mult, div;
398 u32 val;
399 int ret;
400 int i;
401
402 gemini_clk_data = kzalloc(struct_size(gemini_clk_data, hws,
403 GEMINI_NUM_CLKS),
404 GFP_KERNEL);
405 if (!gemini_clk_data)
406 return;
407
408 /*
409 * This way all clock fetched before the platform device probes,
410 * except those we assign here for early use, will be deferred.
411 */
412 for (i = 0; i < GEMINI_NUM_CLKS; i++)
413 gemini_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
414
415 map = syscon_node_to_regmap(np);
416 if (IS_ERR(map)) {
417 pr_err("no syscon regmap\n");
418 return;
419 }
420 /*
421 * We check that the regmap works on this very first access,
422 * but as this is an MMIO-backed regmap, subsequent regmap
423 * access is not going to fail and we skip error checks from
424 * this point.
425 */
426 ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
427 if (ret) {
428 pr_err("failed to read global status register\n");
429 return;
430 }
431
432 /*
433 * XTAL is the crystal oscillator, 60 or 30 MHz selected from
434 * strap pin E6
435 */
436 if (val & PLL_OSC_SEL)
437 freq = 30000000;
438 else
439 freq = 60000000;
440 hw = clk_hw_register_fixed_rate(NULL, "xtal", NULL, 0, freq);
441 pr_debug("main crystal @%lu MHz\n", freq / 1000000);
442
443 /* VCO clock derived from the crystal */
444 mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK);
445 div = 2;
446 /* If we run on 30 MHz crystal we have to multiply with two */
447 if (val & PLL_OSC_SEL)
448 mult *= 2;
449 hw = clk_hw_register_fixed_factor(NULL, "vco", "xtal", 0, mult, div);
450
451 /* The AHB clock is always 1/3 of the VCO */
452 hw = clk_hw_register_fixed_factor(NULL, "ahb", "vco", 0, 1, 3);
453 gemini_clk_data->hws[GEMINI_CLK_AHB] = hw;
454
455 /* The APB clock is always 1/6 of the AHB */
456 hw = clk_hw_register_fixed_factor(NULL, "apb", "ahb", 0, 1, 6);
457 gemini_clk_data->hws[GEMINI_CLK_APB] = hw;
458
459 /* Register the clocks to be accessed by the device tree */
460 gemini_clk_data->num = GEMINI_NUM_CLKS;
461 of_clk_add_hw_provider(np, of_clk_hw_onecell_get, gemini_clk_data);
462}
463CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);
464