1 /*
2 *
3 * Utility functions for the Freescale MPC52xx.
4 *
5 * Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com>
6 *
7 * This file is licensed under the terms of the GNU General Public License
8 * version 2. This program is licensed "as is" without any warranty of any
9 * kind, whether express or implied.
10 *
11 */
12
13 #undef DEBUG
14
15 #include <linux/kernel.h>
16 #include <linux/spinlock.h>
17 #include <linux/of_platform.h>
18 #include <asm/io.h>
19 #include <asm/prom.h>
20 #include <asm/mpc52xx.h>
21
22 /* MPC5200 device tree match tables */
23 static struct of_device_id mpc52xx_xlb_ids[] __initdata = {
24 { .compatible = "fsl,mpc5200-xlb", },
25 { .compatible = "mpc5200-xlb", },
26 {}
27 };
28 static struct of_device_id mpc52xx_bus_ids[] __initdata = {
29 { .compatible = "fsl,mpc5200-immr", },
30 { .compatible = "fsl,mpc5200b-immr", },
31 { .compatible = "fsl,lpb", },
32
33 /* depreciated matches; shouldn't be used in new device trees */
34 { .type = "builtin", .compatible = "mpc5200", }, /* efika */
35 { .type = "soc", .compatible = "mpc5200", }, /* lite5200 */
36 {}
37 };
38
39 /*
40 * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
41 * Permanent mapping is required because mpc52xx_restart() can be called
42 * from interrupt context while node mapping (which calls ioremap())
43 * cannot be used at such point.
44 */
45 static DEFINE_SPINLOCK(mpc52xx_lock);
46 static struct mpc52xx_gpt __iomem *mpc52xx_wdt;
47 static struct mpc52xx_cdm __iomem *mpc52xx_cdm;
48
49 /**
50 * mpc52xx_find_ipb_freq - Find the IPB bus frequency for a device
51 * @node: device node
52 *
53 * Returns IPB bus frequency, or 0 if the bus frequency cannot be found.
54 */
55 unsigned int
mpc52xx_find_ipb_freq(struct device_node * node)56 mpc52xx_find_ipb_freq(struct device_node *node)
57 {
58 struct device_node *np;
59 const unsigned int *p_ipb_freq = NULL;
60
61 of_node_get(node);
62 while (node) {
63 p_ipb_freq = of_get_property(node, "bus-frequency", NULL);
64 if (p_ipb_freq)
65 break;
66
67 np = of_get_parent(node);
68 of_node_put(node);
69 node = np;
70 }
71 if (node)
72 of_node_put(node);
73
74 return p_ipb_freq ? *p_ipb_freq : 0;
75 }
76 EXPORT_SYMBOL(mpc52xx_find_ipb_freq);
77
78
79 /*
80 * Configure the XLB arbiter settings to match what Linux expects.
81 */
82 void __init
mpc5200_setup_xlb_arbiter(void)83 mpc5200_setup_xlb_arbiter(void)
84 {
85 struct device_node *np;
86 struct mpc52xx_xlb __iomem *xlb;
87
88 np = of_find_matching_node(NULL, mpc52xx_xlb_ids);
89 xlb = of_iomap(np, 0);
90 of_node_put(np);
91 if (!xlb) {
92 printk(KERN_ERR __FILE__ ": "
93 "Error mapping XLB in mpc52xx_setup_cpu(). "
94 "Expect some abnormal behavior\n");
95 return;
96 }
97
98 /* Configure the XLB Arbiter priorities */
99 out_be32(&xlb->master_pri_enable, 0xff);
100 out_be32(&xlb->master_priority, 0x11111111);
101
102 /*
103 * Disable XLB pipelining
104 * (cfr errate 292. We could do this only just before ATA PIO
105 * transaction and re-enable it afterwards ...)
106 * Not needed on MPC5200B.
107 */
108 if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR)
109 out_be32(&xlb->config, in_be32(&xlb->config) | MPC52xx_XLB_CFG_PLDIS);
110
111 iounmap(xlb);
112 }
113
114 /**
115 * mpc52xx_declare_of_platform_devices: register internal devices and children
116 * of the localplus bus to the of_platform
117 * bus.
118 */
119 void __init
mpc52xx_declare_of_platform_devices(void)120 mpc52xx_declare_of_platform_devices(void)
121 {
122 /* Find every child of the SOC node and add it to of_platform */
123 if (of_platform_bus_probe(NULL, mpc52xx_bus_ids, NULL))
124 printk(KERN_ERR __FILE__ ": "
125 "Error while probing of_platform bus\n");
126 }
127
128 /*
129 * match tables used by mpc52xx_map_common_devices()
130 */
131 static struct of_device_id mpc52xx_gpt_ids[] __initdata = {
132 { .compatible = "fsl,mpc5200-gpt", },
133 { .compatible = "mpc5200-gpt", }, /* old */
134 {}
135 };
136 static struct of_device_id mpc52xx_cdm_ids[] __initdata = {
137 { .compatible = "fsl,mpc5200-cdm", },
138 { .compatible = "mpc5200-cdm", }, /* old */
139 {}
140 };
141
142 /**
143 * mpc52xx_map_common_devices: iomap devices required by common code
144 */
145 void __init
mpc52xx_map_common_devices(void)146 mpc52xx_map_common_devices(void)
147 {
148 struct device_node *np;
149
150 /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
151 * possibly from a interrupt context. wdt is only implement
152 * on a gpt0, so check has-wdt property before mapping.
153 */
154 for_each_matching_node(np, mpc52xx_gpt_ids) {
155 if (of_get_property(np, "fsl,has-wdt", NULL) ||
156 of_get_property(np, "has-wdt", NULL)) {
157 mpc52xx_wdt = of_iomap(np, 0);
158 of_node_put(np);
159 break;
160 }
161 }
162
163 /* Clock Distribution Module, used by PSC clock setting function */
164 np = of_find_matching_node(NULL, mpc52xx_cdm_ids);
165 mpc52xx_cdm = of_iomap(np, 0);
166 of_node_put(np);
167 }
168
169 /**
170 * mpc52xx_set_psc_clkdiv: Set clock divider in the CDM for PSC ports
171 *
172 * @psc_id: id of psc port; must be 1,2,3 or 6
173 * @clkdiv: clock divider value to put into CDM PSC register.
174 */
mpc52xx_set_psc_clkdiv(int psc_id,int clkdiv)175 int mpc52xx_set_psc_clkdiv(int psc_id, int clkdiv)
176 {
177 unsigned long flags;
178 u16 __iomem *reg;
179 u32 val;
180 u32 mask;
181 u32 mclken_div;
182
183 if (!mpc52xx_cdm)
184 return -ENODEV;
185
186 mclken_div = 0x8000 | (clkdiv & 0x1FF);
187 switch (psc_id) {
188 case 1: reg = &mpc52xx_cdm->mclken_div_psc1; mask = 0x20; break;
189 case 2: reg = &mpc52xx_cdm->mclken_div_psc2; mask = 0x40; break;
190 case 3: reg = &mpc52xx_cdm->mclken_div_psc3; mask = 0x80; break;
191 case 6: reg = &mpc52xx_cdm->mclken_div_psc6; mask = 0x10; break;
192 default:
193 return -ENODEV;
194 }
195
196 /* Set the rate and enable the clock */
197 spin_lock_irqsave(&mpc52xx_lock, flags);
198 out_be16(reg, mclken_div);
199 val = in_be32(&mpc52xx_cdm->clk_enables);
200 out_be32(&mpc52xx_cdm->clk_enables, val | mask);
201 spin_unlock_irqrestore(&mpc52xx_lock, flags);
202
203 return 0;
204 }
205 EXPORT_SYMBOL(mpc52xx_set_psc_clkdiv);
206
207 /**
208 * mpc52xx_restart: ppc_md->restart hook for mpc5200 using the watchdog timer
209 */
210 void
mpc52xx_restart(char * cmd)211 mpc52xx_restart(char *cmd)
212 {
213 local_irq_disable();
214
215 /* Turn on the watchdog and wait for it to expire.
216 * It effectively does a reset. */
217 if (mpc52xx_wdt) {
218 out_be32(&mpc52xx_wdt->mode, 0x00000000);
219 out_be32(&mpc52xx_wdt->count, 0x000000ff);
220 out_be32(&mpc52xx_wdt->mode, 0x00009004);
221 } else
222 printk(KERN_ERR __FILE__ ": "
223 "mpc52xx_restart: Can't access wdt. "
224 "Restart impossible, system halted.\n");
225
226 while (1);
227 }
228