xref: /openbmc/linux/arch/arm/mach-pxa/smemc.c (revision 0d727e18)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Static Memory Controller
4  */
5 
6 #include <linux/module.h>
7 #include <linux/kernel.h>
8 #include <linux/init.h>
9 #include <linux/io.h>
10 #include <linux/syscore_ops.h>
11 #include <linux/soc/pxa/cpu.h>
12 
13 #include "smemc.h"
14 #include <linux/soc/pxa/smemc.h>
15 
16 #ifdef CONFIG_PM
17 static unsigned long msc[2];
18 static unsigned long sxcnfg, memclkcfg;
19 static unsigned long csadrcfg[4];
20 
21 static int pxa3xx_smemc_suspend(void)
22 {
23 	msc[0] = __raw_readl(MSC0);
24 	msc[1] = __raw_readl(MSC1);
25 	sxcnfg = __raw_readl(SXCNFG);
26 	memclkcfg = __raw_readl(MEMCLKCFG);
27 	csadrcfg[0] = __raw_readl(CSADRCFG0);
28 	csadrcfg[1] = __raw_readl(CSADRCFG1);
29 	csadrcfg[2] = __raw_readl(CSADRCFG2);
30 	csadrcfg[3] = __raw_readl(CSADRCFG3);
31 
32 	return 0;
33 }
34 
35 static void pxa3xx_smemc_resume(void)
36 {
37 	__raw_writel(msc[0], MSC0);
38 	__raw_writel(msc[1], MSC1);
39 	__raw_writel(sxcnfg, SXCNFG);
40 	__raw_writel(memclkcfg, MEMCLKCFG);
41 	__raw_writel(csadrcfg[0], CSADRCFG0);
42 	__raw_writel(csadrcfg[1], CSADRCFG1);
43 	__raw_writel(csadrcfg[2], CSADRCFG2);
44 	__raw_writel(csadrcfg[3], CSADRCFG3);
45 	/* CSMSADRCFG wakes up in its default state (0), so we need to set it */
46 	__raw_writel(0x2, CSMSADRCFG);
47 }
48 
49 static struct syscore_ops smemc_syscore_ops = {
50 	.suspend	= pxa3xx_smemc_suspend,
51 	.resume		= pxa3xx_smemc_resume,
52 };
53 
54 static int __init smemc_init(void)
55 {
56 	if (cpu_is_pxa3xx()) {
57 		/*
58 		 * The only documentation we have on the
59 		 * Chip Select Configuration Register (CSMSADRCFG) is that
60 		 * it must be programmed to 0x2.
61 		 * Moreover, in the bit definitions, the second bit
62 		 * (CSMSADRCFG[1]) is called "SETALWAYS".
63 		 * Other bits are reserved in this register.
64 		 */
65 		__raw_writel(0x2, CSMSADRCFG);
66 
67 		register_syscore_ops(&smemc_syscore_ops);
68 	}
69 
70 	return 0;
71 }
72 subsys_initcall(smemc_init);
73 #endif
74 
75 static const unsigned int df_clkdiv[4] = { 1, 2, 4, 1 };
76 unsigned int pxa3xx_smemc_get_memclkdiv(void)
77 {
78 	unsigned long memclkcfg = __raw_readl(MEMCLKCFG);
79 
80 	return	df_clkdiv[(memclkcfg >> 16) & 0x3];
81 }
82