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 */
50static 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 */
85static 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, reg: &idlest_reg, mask: (1 << idlest_bit),
106 idlest: idlest_val, name: clk_hw_get_name(hw: &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 */
134void 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 */
163void 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 */
194int 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 */
243void 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 */
271int 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
286const 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

source code of linux/drivers/clk/ti/clkt_dflt.c