1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * System clock support for AT91 architectures.
4 *
5 * Copyright (C) Microchip Technology Inc. and its subsidiaries
6 *
7 * Author: Claudiu Beznea <claudiu.beznea@microchip.com>
8 *
9 * Based on drivers/clk/at91/clk-system.c from Linux.
10 */
11 #include <asm/processor.h>
12 #include <common.h>
13 #include <clk-uclass.h>
14 #include <dm.h>
15 #include <linux/io.h>
16 #include <linux/clk-provider.h>
17 #include <linux/clk/at91_pmc.h>
18
19 #include "pmc.h"
20
21 #define UBOOT_DM_CLK_AT91_SYSTEM "at91-system-clk"
22
23 #define SYSTEM_MAX_ID 31
24
25 struct clk_system {
26 void __iomem *base;
27 struct clk clk;
28 u8 id;
29 };
30
31 #define to_clk_system(_c) container_of(_c, struct clk_system, clk)
32
is_pck(int id)33 static inline int is_pck(int id)
34 {
35 return (id >= 8) && (id <= 15);
36 }
37
clk_system_ready(void __iomem * base,int id)38 static inline bool clk_system_ready(void __iomem *base, int id)
39 {
40 unsigned int status;
41
42 pmc_read(base, AT91_PMC_SR, &status);
43
44 return !!(status & (1 << id));
45 }
46
clk_system_enable(struct clk * clk)47 static int clk_system_enable(struct clk *clk)
48 {
49 struct clk_system *sys = to_clk_system(clk);
50
51 pmc_write(sys->base, AT91_PMC_SCER, 1 << sys->id);
52
53 if (!is_pck(sys->id))
54 return 0;
55
56 while (!clk_system_ready(sys->base, sys->id)) {
57 debug("waiting for pck%u\n", sys->id);
58 cpu_relax();
59 }
60
61 return 0;
62 }
63
clk_system_disable(struct clk * clk)64 static int clk_system_disable(struct clk *clk)
65 {
66 struct clk_system *sys = to_clk_system(clk);
67
68 pmc_write(sys->base, AT91_PMC_SCDR, 1 << sys->id);
69
70 return 0;
71 }
72
73 static const struct clk_ops system_ops = {
74 .enable = clk_system_enable,
75 .disable = clk_system_disable,
76 .get_rate = clk_generic_get_rate,
77 };
78
at91_clk_register_system(void __iomem * base,const char * name,const char * parent_name,u8 id)79 struct clk *at91_clk_register_system(void __iomem *base, const char *name,
80 const char *parent_name, u8 id)
81 {
82 struct clk_system *sys;
83 struct clk *clk;
84 int ret;
85
86 if (!base || !name || !parent_name || id > SYSTEM_MAX_ID)
87 return ERR_PTR(-EINVAL);
88
89 sys = kzalloc(sizeof(*sys), GFP_KERNEL);
90 if (!sys)
91 return ERR_PTR(-ENOMEM);
92
93 sys->id = id;
94 sys->base = base;
95
96 clk = &sys->clk;
97 clk->flags = CLK_GET_RATE_NOCACHE;
98 ret = clk_register(clk, UBOOT_DM_CLK_AT91_SYSTEM, name, parent_name);
99 if (ret) {
100 kfree(sys);
101 clk = ERR_PTR(ret);
102 }
103
104 return clk;
105 }
106
107 U_BOOT_DRIVER(at91_system_clk) = {
108 .name = UBOOT_DM_CLK_AT91_SYSTEM,
109 .id = UCLASS_CLK,
110 .ops = &system_ops,
111 .flags = DM_FLAG_PRE_RELOC,
112 };
113