xref: /openbmc/linux/drivers/clk/ti/clkt_dflt.c (revision 5a729246)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Default clock type
4  *
5  * Copyright (C) 2005-2008, 2015 Texas Instruments, Inc.
6  * Copyright (C) 2004-2010 Nokia Corporation
7  *
8  * Contacts:
9  * Richard Woodruff <r-woodruff2@ti.com>
10  * Paul Walmsley
11  * Tero Kristo <t-kristo@ti.com>
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/clk-provider.h>
17 #include <linux/io.h>
18 #include <linux/clk/ti.h>
19 #include <linux/delay.h>
20 
21 #include "clock.h"
22 
23 /*
24  * MAX_MODULE_ENABLE_WAIT: maximum of number of microseconds to wait
25  * for a module to indicate that it is no longer in idle
26  */
27 #define MAX_MODULE_ENABLE_WAIT		100000
28 
29 /*
30  * CM module register offsets, used for calculating the companion
31  * register addresses.
32  */
33 #define CM_FCLKEN			0x0000
34 #define CM_ICLKEN			0x0010
35 
36 /**
37  * _wait_idlest_generic - wait for a module to leave the idle state
38  * @clk: module clock to wait for (needed for register offsets)
39  * @reg: virtual address of module IDLEST register
40  * @mask: value to mask against to determine if the module is active
41  * @idlest: idle state indicator (0 or 1) for the clock
42  * @name: name of the clock (for printk)
43  *
44  * Wait for a module to leave idle, where its idle-status register is
45  * not inside the CM module.  Returns 1 if the module left idle
46  * promptly, or 0 if the module did not leave idle before the timeout
47  * elapsed.  XXX Deprecated - should be moved into drivers for the
48  * individual IP block that the IDLEST register exists in.
49  */
_wait_idlest_generic(struct clk_hw_omap * clk,struct clk_omap_reg * reg,u32 mask,u8 idlest,const char * name)50 static int _wait_idlest_generic(struct clk_hw_omap *clk,
51 				struct clk_omap_reg *reg,
52 				u32 mask, u8 idlest, const char *name)
53 {
54 	int i = 0, ena = 0;
55 
56 	ena = (idlest) ? 0 : mask;
57 
58 	/* Wait until module enters enabled state */
59 	for (i = 0; i < MAX_MODULE_ENABLE_WAIT; i++) {
60 		if ((ti_clk_ll_ops->clk_readl(reg) & mask) == ena)
61 			break;
62 		udelay(1);
63 	}
64 
65 	if (i < MAX_MODULE_ENABLE_WAIT)
66 		pr_debug("omap clock: module associated with clock %s ready after %d loops\n",
67 			 name, i);
68 	else
69 		pr_err("omap clock: module associated with clock %s didn't enable in %d tries\n",
70 		       name, MAX_MODULE_ENABLE_WAIT);
71 
72 	return (i < MAX_MODULE_ENABLE_WAIT) ? 1 : 0;
73 }
74 
75 /**
76  * _omap2_module_wait_ready - wait for an OMAP module to leave IDLE
77  * @clk: struct clk * belonging to the module
78  *
79  * If the necessary clocks for the OMAP hardware IP block that
80  * corresponds to clock @clk are enabled, then wait for the module to
81  * indicate readiness (i.e., to leave IDLE).  This code does not
82  * belong in the clock code and will be moved in the medium term to
83  * module-dependent code.  No return value.
84  */
_omap2_module_wait_ready(struct clk_hw_omap * clk)85 static void _omap2_module_wait_ready(struct clk_hw_omap *clk)
86 {
87 	struct clk_omap_reg companion_reg, idlest_reg;
88 	u8 other_bit, idlest_bit, idlest_val, idlest_reg_id;
89 	s16 prcm_mod;
90 	int r;
91 
92 	/* Not all modules have multiple clocks that their IDLEST depends on */
93 	if (clk->ops->find_companion) {
94 		clk->ops->find_companion(clk, &companion_reg, &other_bit);
95 		if (!(ti_clk_ll_ops->clk_readl(&companion_reg) &
96 		      (1 << other_bit)))
97 			return;
98 	}
99 
100 	clk->ops->find_idlest(clk, &idlest_reg, &idlest_bit, &idlest_val);
101 	r = ti_clk_ll_ops->cm_split_idlest_reg(&idlest_reg, &prcm_mod,
102 					       &idlest_reg_id);
103 	if (r) {
104 		/* IDLEST register not in the CM module */
105 		_wait_idlest_generic(clk, &idlest_reg, (1 << idlest_bit),
106 				     idlest_val, clk_hw_get_name(&clk->hw));
107 	} else {
108 		ti_clk_ll_ops->cm_wait_module_ready(0, prcm_mod, idlest_reg_id,
109 						    idlest_bit);
110 	}
111 }
112 
113 /**
114  * omap2_clk_dflt_find_companion - find companion clock to @clk
115  * @clk: struct clk * to find the companion clock of
116  * @other_reg: void __iomem ** to return the companion clock CM_*CLKEN va in
117  * @other_bit: u8 ** to return the companion clock bit shift in
118  *
119  * Note: We don't need special code here for INVERT_ENABLE for the
120  * time being since INVERT_ENABLE only applies to clocks enabled by
121  * CM_CLKEN_PLL
122  *
123  * Convert CM_ICLKEN* <-> CM_FCLKEN*.  This conversion assumes it's
124  * just a matter of XORing the bits.
125  *
126  * Some clocks don't have companion clocks.  For example, modules with
127  * only an interface clock (such as MAILBOXES) don't have a companion
128  * clock.  Right now, this code relies on the hardware exporting a bit
129  * in the correct companion register that indicates that the
130  * nonexistent 'companion clock' is active.  Future patches will
131  * associate this type of code with per-module data structures to
132  * avoid this issue, and remove the casts.  No return value.
133  */
omap2_clk_dflt_find_companion(struct clk_hw_omap * clk,struct clk_omap_reg * other_reg,u8 * other_bit)134 void omap2_clk_dflt_find_companion(struct clk_hw_omap *clk,
135 				   struct clk_omap_reg *other_reg,
136 				   u8 *other_bit)
137 {
138 	memcpy(other_reg, &clk->enable_reg, sizeof(*other_reg));
139 
140 	/*
141 	 * Convert CM_ICLKEN* <-> CM_FCLKEN*.  This conversion assumes
142 	 * it's just a matter of XORing the bits.
143 	 */
144 	other_reg->offset ^= (CM_FCLKEN ^ CM_ICLKEN);
145 
146 	*other_bit = clk->enable_bit;
147 }
148 
149 /**
150  * omap2_clk_dflt_find_idlest - find CM_IDLEST reg va, bit shift for @clk
151  * @clk: struct clk * to find IDLEST info for
152  * @idlest_reg: void __iomem ** to return the CM_IDLEST va in
153  * @idlest_bit: u8 * to return the CM_IDLEST bit shift in
154  * @idlest_val: u8 * to return the idle status indicator
155  *
156  * Return the CM_IDLEST register address and bit shift corresponding
157  * to the module that "owns" this clock.  This default code assumes
158  * that the CM_IDLEST bit shift is the CM_*CLKEN bit shift, and that
159  * the IDLEST register address ID corresponds to the CM_*CLKEN
160  * register address ID (e.g., that CM_FCLKEN2 corresponds to
161  * CM_IDLEST2).  This is not true for all modules.  No return value.
162  */
omap2_clk_dflt_find_idlest(struct clk_hw_omap * clk,struct clk_omap_reg * idlest_reg,u8 * idlest_bit,u8 * idlest_val)163 void omap2_clk_dflt_find_idlest(struct clk_hw_omap *clk,
164 				struct clk_omap_reg *idlest_reg, u8 *idlest_bit,
165 				u8 *idlest_val)
166 {
167 	memcpy(idlest_reg, &clk->enable_reg, sizeof(*idlest_reg));
168 
169 	idlest_reg->offset &= ~0xf0;
170 	idlest_reg->offset |= 0x20;
171 
172 	*idlest_bit = clk->enable_bit;
173 
174 	/*
175 	 * 24xx uses 0 to indicate not ready, and 1 to indicate ready.
176 	 * 34xx reverses this, just to keep us on our toes
177 	 * AM35xx uses both, depending on the module.
178 	 */
179 	*idlest_val = ti_clk_get_features()->cm_idlest_val;
180 }
181 
182 /**
183  * omap2_dflt_clk_enable - enable a clock in the hardware
184  * @hw: struct clk_hw * of the clock to enable
185  *
186  * Enable the clock @hw in the hardware.  We first call into the OMAP
187  * clockdomain code to "enable" the corresponding clockdomain if this
188  * is the first enabled user of the clockdomain.  Then program the
189  * hardware to enable the clock.  Then wait for the IP block that uses
190  * this clock to leave idle (if applicable).  Returns the error value
191  * from clkdm_clk_enable() if it terminated with an error, or -EINVAL
192  * if @hw has a null clock enable_reg, or zero upon success.
193  */
omap2_dflt_clk_enable(struct clk_hw * hw)194 int omap2_dflt_clk_enable(struct clk_hw *hw)
195 {
196 	struct clk_hw_omap *clk;
197 	u32 v;
198 	int ret = 0;
199 	bool clkdm_control;
200 
201 	if (ti_clk_get_features()->flags & TI_CLK_DISABLE_CLKDM_CONTROL)
202 		clkdm_control = false;
203 	else
204 		clkdm_control = true;
205 
206 	clk = to_clk_hw_omap(hw);
207 
208 	if (clkdm_control && clk->clkdm) {
209 		ret = ti_clk_ll_ops->clkdm_clk_enable(clk->clkdm, hw->clk);
210 		if (ret) {
211 			WARN(1,
212 			     "%s: could not enable %s's clockdomain %s: %d\n",
213 			     __func__, clk_hw_get_name(hw),
214 			     clk->clkdm_name, ret);
215 			return ret;
216 		}
217 	}
218 
219 	/* FIXME should not have INVERT_ENABLE bit here */
220 	v = ti_clk_ll_ops->clk_readl(&clk->enable_reg);
221 	if (clk->flags & INVERT_ENABLE)
222 		v &= ~(1 << clk->enable_bit);
223 	else
224 		v |= (1 << clk->enable_bit);
225 	ti_clk_ll_ops->clk_writel(v, &clk->enable_reg);
226 	v = ti_clk_ll_ops->clk_readl(&clk->enable_reg); /* OCP barrier */
227 
228 	if (clk->ops && clk->ops->find_idlest)
229 		_omap2_module_wait_ready(clk);
230 
231 	return 0;
232 }
233 
234 /**
235  * omap2_dflt_clk_disable - disable a clock in the hardware
236  * @hw: struct clk_hw * of the clock to disable
237  *
238  * Disable the clock @hw in the hardware, and call into the OMAP
239  * clockdomain code to "disable" the corresponding clockdomain if all
240  * clocks/hwmods in that clockdomain are now disabled.  No return
241  * value.
242  */
omap2_dflt_clk_disable(struct clk_hw * hw)243 void omap2_dflt_clk_disable(struct clk_hw *hw)
244 {
245 	struct clk_hw_omap *clk;
246 	u32 v;
247 
248 	clk = to_clk_hw_omap(hw);
249 
250 	v = ti_clk_ll_ops->clk_readl(&clk->enable_reg);
251 	if (clk->flags & INVERT_ENABLE)
252 		v |= (1 << clk->enable_bit);
253 	else
254 		v &= ~(1 << clk->enable_bit);
255 	ti_clk_ll_ops->clk_writel(v, &clk->enable_reg);
256 	/* No OCP barrier needed here since it is a disable operation */
257 
258 	if (!(ti_clk_get_features()->flags & TI_CLK_DISABLE_CLKDM_CONTROL) &&
259 	    clk->clkdm)
260 		ti_clk_ll_ops->clkdm_clk_disable(clk->clkdm, hw->clk);
261 }
262 
263 /**
264  * omap2_dflt_clk_is_enabled - is clock enabled in the hardware?
265  * @hw: struct clk_hw * to check
266  *
267  * Return 1 if the clock represented by @hw is enabled in the
268  * hardware, or 0 otherwise.  Intended for use in the struct
269  * clk_ops.is_enabled function pointer.
270  */
omap2_dflt_clk_is_enabled(struct clk_hw * hw)271 int omap2_dflt_clk_is_enabled(struct clk_hw *hw)
272 {
273 	struct clk_hw_omap *clk = to_clk_hw_omap(hw);
274 	u32 v;
275 
276 	v = ti_clk_ll_ops->clk_readl(&clk->enable_reg);
277 
278 	if (clk->flags & INVERT_ENABLE)
279 		v ^= BIT(clk->enable_bit);
280 
281 	v &= BIT(clk->enable_bit);
282 
283 	return v ? 1 : 0;
284 }
285 
286 const struct clk_hw_omap_ops clkhwops_wait = {
287 	.find_idlest	= omap2_clk_dflt_find_idlest,
288 	.find_companion	= omap2_clk_dflt_find_companion,
289 };
290