summaryrefslogtreecommitdiff
path: root/drivers/clk/clk-gemini.c
blob: ba0ff01bf4dc4efa4baeaac3643d31dca396af35 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
// SPDX-License-Identifier: GPL-2.0
/*
 * Cortina Gemini SoC Clock Controller driver
 * Copyright (c) 2017 Linus Walleij <linus.walleij@linaro.org>
 */

#define pr_fmt(fmt) "clk-gemini: " fmt

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk-provider.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/spinlock.h>
#include <linux/reset-controller.h>
#include <dt-bindings/reset/cortina,gemini-reset.h>
#include <dt-bindings/clock/cortina,gemini-clock.h>

/* Globally visible clocks */
static DEFINE_SPINLOCK(gemini_clk_lock);

#define GEMINI_GLOBAL_STATUS		0x04
#define PLL_OSC_SEL			BIT(30)
#define AHBSPEED_SHIFT			(15)
#define AHBSPEED_MASK			0x07
#define CPU_AHB_RATIO_SHIFT		(18)
#define CPU_AHB_RATIO_MASK		0x03

#define GEMINI_GLOBAL_PLL_CONTROL	0x08

#define GEMINI_GLOBAL_SOFT_RESET	0x0c

#define GEMINI_GLOBAL_MISC_CONTROL	0x30
#define PCI_CLK_66MHZ			BIT(18)

#define GEMINI_GLOBAL_CLOCK_CONTROL	0x34
#define PCI_CLKRUN_EN			BIT(16)
#define TVC_HALFDIV_SHIFT		(24)
#define TVC_HALFDIV_MASK		0x1f
#define SECURITY_CLK_SEL		BIT(29)

#define GEMINI_GLOBAL_PCI_DLL_CONTROL	0x44
#define PCI_DLL_BYPASS			BIT(31)
#define PCI_DLL_TAP_SEL_MASK		0x1f

/**
 * struct gemini_gate_data - Gemini gated clocks
 * @bit_idx: the bit used to gate this clock in the clock register
 * @name: the clock name
 * @parent_name: the name of the parent clock
 * @flags: standard clock framework flags
 */
struct gemini_gate_data {
	u8 bit_idx;
	const char *name;
	const char *parent_name;
	unsigned long flags;
};

/**
 * struct clk_gemini_pci - Gemini PCI clock
 * @hw: corresponding clock hardware entry
 * @map: regmap to access the registers
 * @rate: current rate
 */
struct clk_gemini_pci {
	struct clk_hw hw;
	struct regmap *map;
	unsigned long rate;
};

/**
 * struct gemini_reset - gemini reset controller
 * @map: regmap to access the containing system controller
 * @rcdev: reset controller device
 */
struct gemini_reset {
	struct regmap *map;
	struct reset_controller_dev rcdev;
};

/* Keeps track of all clocks */
static struct clk_hw_onecell_data *gemini_clk_data;

static const struct gemini_gate_data gemini_gates[] = {
	{ 1, "security-gate", "secdiv", 0 },
	{ 2, "gmac0-gate", "ahb", 0 },
	{ 3, "gmac1-gate", "ahb", 0 },
	{ 4, "sata0-gate", "ahb", 0 },
	{ 5, "sata1-gate", "ahb", 0 },
	{ 6, "usb0-gate", "ahb", 0 },
	{ 7, "usb1-gate", "ahb", 0 },
	{ 8, "ide-gate", "ahb", 0 },
	{ 9, "pci-gate", "ahb", 0 },
	/*
	 * The DDR controller may never have a driver, but certainly must
	 * not be gated off.
	 */
	{ 10, "ddr-gate", "ahb", CLK_IS_CRITICAL },
	/*
	 * The flash controller must be on to access NOR flash through the
	 * memory map.
	 */
	{ 11, "flash-gate", "ahb", CLK_IGNORE_UNUSED },
	{ 12, "tvc-gate", "ahb", 0 },
	{ 13, "boot-gate", "apb", 0 },
};

#define to_pciclk(_hw) container_of(_hw, struct clk_gemini_pci, hw)

#define to_gemini_reset(p) container_of((p), struct gemini_reset, rcdev)

static unsigned long gemini_pci_recalc_rate(struct clk_hw *hw,
					    unsigned long parent_rate)
{
	struct clk_gemini_pci *pciclk = to_pciclk(hw);
	u32 val;

	regmap_read(pciclk->map, GEMINI_GLOBAL_MISC_CONTROL, &val);
	if (val & PCI_CLK_66MHZ)
		return 66000000;
	return 33000000;
}

static long gemini_pci_round_rate(struct clk_hw *hw, unsigned long rate,
				  unsigned long *prate)
{
	/* We support 33 and 66 MHz */
	if (rate < 48000000)
		return 33000000;
	return 66000000;
}

static int gemini_pci_set_rate(struct clk_hw *hw, unsigned long rate,
			       unsigned long parent_rate)
{
	struct clk_gemini_pci *pciclk = to_pciclk(hw);

	if (rate == 33000000)
		return regmap_update_bits(pciclk->map,
					  GEMINI_GLOBAL_MISC_CONTROL,
					  PCI_CLK_66MHZ, 0);
	if (rate == 66000000)
		return regmap_update_bits(pciclk->map,
					  GEMINI_GLOBAL_MISC_CONTROL,
					  0, PCI_CLK_66MHZ);
	return -EINVAL;
}

static int gemini_pci_enable(struct clk_hw *hw)
{
	struct clk_gemini_pci *pciclk = to_pciclk(hw);

	regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
			   0, PCI_CLKRUN_EN);
	return 0;
}

static void gemini_pci_disable(struct clk_hw *hw)
{
	struct clk_gemini_pci *pciclk = to_pciclk(hw);

	regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
			   PCI_CLKRUN_EN, 0);
}

static int gemini_pci_is_enabled(struct clk_hw *hw)
{
	struct clk_gemini_pci *pciclk = to_pciclk(hw);
	unsigned int val;

	regmap_read(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
	return !!(val & PCI_CLKRUN_EN);
}

static const struct clk_ops gemini_pci_clk_ops = {
	.recalc_rate = gemini_pci_recalc_rate,
	.round_rate = gemini_pci_round_rate,
	.set_rate = gemini_pci_set_rate,
	.enable = gemini_pci_enable,
	.disable = gemini_pci_disable,
	.is_enabled = gemini_pci_is_enabled,
};

static struct clk_hw *gemini_pci_clk_setup(const char *name,
					   const char *parent_name,
					   struct regmap *map)
{
	struct clk_gemini_pci *pciclk;
	struct clk_init_data init;
	int ret;

	pciclk = kzalloc(sizeof(*pciclk), GFP_KERNEL);
	if (!pciclk)
		return ERR_PTR(-ENOMEM);

	init.name = name;
	init.ops = &gemini_pci_clk_ops;
	init.flags = 0;
	init.parent_names = &parent_name;
	init.num_parents = 1;
	pciclk->map = map;
	pciclk->hw.init = &init;

	ret = clk_hw_register(NULL, &pciclk->hw);
	if (ret) {
		kfree(pciclk);
		return ERR_PTR(ret);
	}

	return &pciclk->hw;
}

/*
 * This is a self-deasserting reset controller.
 */
static int gemini_reset(struct reset_controller_dev *rcdev,
			unsigned long id)
{
	struct gemini_reset *gr = to_gemini_reset(rcdev);

	/* Manual says to always set BIT 30 (CPU1) to 1 */
	return regmap_write(gr->map,
			    GEMINI_GLOBAL_SOFT_RESET,
			    BIT(GEMINI_RESET_CPU1) | BIT(id));
}

static int gemini_reset_assert(struct reset_controller_dev *rcdev,
			       unsigned long id)
{
	return 0;
}

static int gemini_reset_deassert(struct reset_controller_dev *rcdev,
				 unsigned long id)
{
	return 0;
}

static int gemini_reset_status(struct reset_controller_dev *rcdev,
			     unsigned long id)
{
	struct gemini_reset *gr = to_gemini_reset(rcdev);
	u32 val;
	int ret;

	ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val);
	if (ret)
		return ret;

	return !!(val & BIT(id));
}

static const struct reset_control_ops gemini_reset_ops = {
	.reset = gemini_reset,
	.assert = gemini_reset_assert,
	.deassert = gemini_reset_deassert,
	.status = gemini_reset_status,
};

static int gemini_clk_probe(struct platform_device *pdev)
{
	/* Gives the fracions 1x, 1.5x, 1.85x and 2x */
	unsigned int cpu_ahb_mult[4] = { 1, 3, 24, 2 };
	unsigned int cpu_ahb_div[4] = { 1, 2, 13, 1 };
	void __iomem *base;
	struct gemini_reset *gr;
	struct regmap *map;
	struct clk_hw *hw;
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	unsigned int mult, div;
	u32 val;
	int ret;
	int i;

	gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL);
	if (!gr)
		return -ENOMEM;

	/* Remap the system controller for the exclusive register */
	base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(base))
		return PTR_ERR(base);

	map = syscon_node_to_regmap(np);
	if (IS_ERR(map)) {
		dev_err(dev, "no syscon regmap\n");
		return PTR_ERR(map);
	}

	gr->map = map;
	gr->rcdev.owner = THIS_MODULE;
	gr->rcdev.nr_resets = 32;
	gr->rcdev.ops = &gemini_reset_ops;
	gr->rcdev.of_node = np;

	ret = devm_reset_controller_register(dev, &gr->rcdev);
	if (ret) {
		dev_err(dev, "could not register reset controller\n");
		return ret;
	}

	/* RTC clock 32768 Hz */
	hw = clk_hw_register_fixed_rate(NULL, "rtc", NULL, 0, 32768);
	gemini_clk_data->hws[GEMINI_CLK_RTC] = hw;

	/* CPU clock derived as a fixed ratio from the AHB clock */
	regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
	val >>= CPU_AHB_RATIO_SHIFT;
	val &= CPU_AHB_RATIO_MASK;
	hw = clk_hw_register_fixed_factor(NULL, "cpu", "ahb", 0,
					  cpu_ahb_mult[val],
					  cpu_ahb_div[val]);
	gemini_clk_data->hws[GEMINI_CLK_CPU] = hw;

	/* Security clock is 1:1 or 0.75 of APB */
	regmap_read(map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
	if (val & SECURITY_CLK_SEL) {
		mult = 1;
		div = 1;
	} else {
		mult = 3;
		div = 4;
	}
	hw = clk_hw_register_fixed_factor(NULL, "secdiv", "ahb", 0, mult, div);

	/*
	 * These are the leaf gates, at boot no clocks are gated.
	 */
	for (i = 0; i < ARRAY_SIZE(gemini_gates); i++) {
		const struct gemini_gate_data *gd;

		gd = &gemini_gates[i];
		gemini_clk_data->hws[GEMINI_CLK_GATES + i] =
			clk_hw_register_gate(NULL, gd->name,
					     gd->parent_name,
					     gd->flags,
					     base + GEMINI_GLOBAL_CLOCK_CONTROL,
					     gd->bit_idx,
					     CLK_GATE_SET_TO_DISABLE,
					     &gemini_clk_lock);
	}

	/*
	 * The TV Interface Controller has a 5-bit half divider register.
	 * This clock is supposed to be 27MHz as this is an exact multiple
	 * of PAL and NTSC frequencies. The register is undocumented :(
	 * FIXME: figure out the parent and how the divider works.
	 */
	mult = 1;
	div = ((val >> TVC_HALFDIV_SHIFT) & TVC_HALFDIV_MASK);
	dev_dbg(dev, "TVC half divider value = %d\n", div);
	div += 1;
	hw = clk_hw_register_fixed_rate(NULL, "tvcdiv", "xtal", 0, 27000000);
	gemini_clk_data->hws[GEMINI_CLK_TVC] = hw;

	/* FIXME: very unclear what the parent is */
	hw = gemini_pci_clk_setup("PCI", "xtal", map);
	gemini_clk_data->hws[GEMINI_CLK_PCI] = hw;

	/* FIXME: very unclear what the parent is */
	hw = clk_hw_register_fixed_rate(NULL, "uart", "xtal", 0, 48000000);
	gemini_clk_data->hws[GEMINI_CLK_UART] = hw;

	return 0;
}

static const struct of_device_id gemini_clk_dt_ids[] = {
	{ .compatible = "cortina,gemini-syscon", },
	{ /* sentinel */ },
};

static struct platform_driver gemini_clk_driver = {
	.probe  = gemini_clk_probe,
	.driver = {
		.name = "gemini-clk",
		.of_match_table = gemini_clk_dt_ids,
		.suppress_bind_attrs = true,
	},
};
builtin_platform_driver(gemini_clk_driver);

static void __init gemini_cc_init(struct device_node *np)
{
	struct regmap *map;
	struct clk_hw *hw;
	unsigned long freq;
	unsigned int mult, div;
	u32 val;
	int ret;
	int i;

	gemini_clk_data = kzalloc(struct_size(gemini_clk_data, hws,
					      GEMINI_NUM_CLKS),
				  GFP_KERNEL);
	if (!gemini_clk_data)
		return;
	gemini_clk_data->num = GEMINI_NUM_CLKS;

	/*
	 * This way all clock fetched before the platform device probes,
	 * except those we assign here for early use, will be deferred.
	 */
	for (i = 0; i < GEMINI_NUM_CLKS; i++)
		gemini_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);

	map = syscon_node_to_regmap(np);
	if (IS_ERR(map)) {
		pr_err("no syscon regmap\n");
		return;
	}
	/*
	 * We check that the regmap works on this very first access,
	 * but as this is an MMIO-backed regmap, subsequent regmap
	 * access is not going to fail and we skip error checks from
	 * this point.
	 */
	ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
	if (ret) {
		pr_err("failed to read global status register\n");
		return;
	}

	/*
	 * XTAL is the crystal oscillator, 60 or 30 MHz selected from
	 * strap pin E6
	 */
	if (val & PLL_OSC_SEL)
		freq = 30000000;
	else
		freq = 60000000;
	hw = clk_hw_register_fixed_rate(NULL, "xtal", NULL, 0, freq);
	pr_debug("main crystal @%lu MHz\n", freq / 1000000);

	/* VCO clock derived from the crystal */
	mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK);
	div = 2;
	/* If we run on 30 MHz crystal we have to multiply with two */
	if (val & PLL_OSC_SEL)
		mult *= 2;
	hw = clk_hw_register_fixed_factor(NULL, "vco", "xtal", 0, mult, div);

	/* The AHB clock is always 1/3 of the VCO */
	hw = clk_hw_register_fixed_factor(NULL, "ahb", "vco", 0, 1, 3);
	gemini_clk_data->hws[GEMINI_CLK_AHB] = hw;

	/* The APB clock is always 1/6 of the AHB */
	hw = clk_hw_register_fixed_factor(NULL, "apb", "ahb", 0, 1, 6);
	gemini_clk_data->hws[GEMINI_CLK_APB] = hw;

	/* Register the clocks to be accessed by the device tree */
	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, gemini_clk_data);
}
CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);