1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CPU idle for DaVinci SoCs
4  *
5  * Copyright (C) 2009 Texas Instruments Incorporated. https://www.ti.com/
6  *
7  * Derived from Marvell Kirkwood CPU idle code
8  * (arch/arm/mach-kirkwood/cpuidle.c)
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/platform_device.h>
14 #include <linux/cpuidle.h>
15 #include <linux/io.h>
16 #include <linux/export.h>
17 #include <asm/cpuidle.h>
18 
19 #include "cpuidle.h"
20 #include "ddr2.h"
21 
22 #define DAVINCI_CPUIDLE_MAX_STATES	2
23 
24 static void __iomem *ddr2_reg_base;
25 static bool ddr2_pdown;
26 
davinci_save_ddr_power(int enter,bool pdown)27 static void davinci_save_ddr_power(int enter, bool pdown)
28 {
29 	u32 val;
30 
31 	val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
32 
33 	if (enter) {
34 		if (pdown)
35 			val |= DDR2_SRPD_BIT;
36 		else
37 			val &= ~DDR2_SRPD_BIT;
38 		val |= DDR2_LPMODEN_BIT;
39 	} else {
40 		val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
41 	}
42 
43 	__raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
44 }
45 
46 /* Actual code that puts the SoC in different idle states */
davinci_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)47 static int davinci_enter_idle(struct cpuidle_device *dev,
48 			      struct cpuidle_driver *drv, int index)
49 {
50 	davinci_save_ddr_power(1, ddr2_pdown);
51 	cpu_do_idle();
52 	davinci_save_ddr_power(0, ddr2_pdown);
53 
54 	return index;
55 }
56 
57 static struct cpuidle_driver davinci_idle_driver = {
58 	.name			= "cpuidle-davinci",
59 	.owner			= THIS_MODULE,
60 	.states[0]		= ARM_CPUIDLE_WFI_STATE,
61 	.states[1]		= {
62 		.enter			= davinci_enter_idle,
63 		.exit_latency		= 10,
64 		.target_residency	= 10000,
65 		.name			= "DDR SR",
66 		.desc			= "WFI and DDR Self Refresh",
67 	},
68 	.state_count = DAVINCI_CPUIDLE_MAX_STATES,
69 };
70 
davinci_cpuidle_probe(struct platform_device * pdev)71 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
72 {
73 	struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
74 
75 	if (!pdata) {
76 		dev_err(&pdev->dev, "cannot get platform data\n");
77 		return -ENOENT;
78 	}
79 
80 	ddr2_reg_base = pdata->ddr2_ctlr_base;
81 
82 	ddr2_pdown = pdata->ddr2_pdown;
83 
84 	return cpuidle_register(&davinci_idle_driver, NULL);
85 }
86 
87 static struct platform_driver davinci_cpuidle_driver = {
88 	.driver = {
89 		.name	= "cpuidle-davinci",
90 	},
91 };
92 
davinci_cpuidle_init(void)93 static int __init davinci_cpuidle_init(void)
94 {
95 	return platform_driver_probe(&davinci_cpuidle_driver,
96 						davinci_cpuidle_probe);
97 }
98 device_initcall(davinci_cpuidle_init);
99 
100