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authorClaudiu Beznea <claudiu.beznea@microchip.com>2021-08-30 13:09:27 +0300
committerNicolas Ferre <nicolas.ferre@microchip.com>2021-09-14 18:05:40 +0300
commitac809e7879b15643105795a5f9becb5ef44abd93 (patch)
tree034fd71d5f611bed423e0811409f6aa39826717e /arch/arm/mach-at91
parent6f34662284511a04643b25ad3032adc6fe4689ab (diff)
downloadlinux-ac809e7879b15643105795a5f9becb5ef44abd93.tar.xz
ARM: at91: pm: switch backup area to vbat in backup mode
Backup area is now switched to VDDIN33 at boot (with the help of bootloader). When switching to backup mode we need to switch backup area to VBAT as all the other power sources are cut off. The resuming from backup mode is done with the help of bootloader, so there is no need to do something particular in Linux to restore backup area power source. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Link: https://lore.kernel.org/r/20210830100927.22711-1-claudiu.beznea@microchip.com
Diffstat (limited to 'arch/arm/mach-at91')
-rw-r--r--arch/arm/mach-at91/pm.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index d92afca64b49..8711d6824c1f 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -47,12 +47,26 @@ struct at91_pm_bu {
unsigned long ddr_phy_calibration[BACKUP_DDR_PHY_CALIBRATION];
};
+/*
+ * struct at91_pm_sfrbu_offsets: registers mapping for SFRBU
+ * @pswbu: power switch BU control registers
+ */
+struct at91_pm_sfrbu_regs {
+ struct {
+ u32 key;
+ u32 ctrl;
+ u32 state;
+ u32 softsw;
+ } pswbu;
+};
+
/**
* struct at91_soc_pm - AT91 SoC power management data structure
* @config_shdwc_ws: wakeup sources configuration function for SHDWC
* @config_pmc_ws: wakeup srouces configuration function for PMC
* @ws_ids: wakup sources of_device_id array
* @data: PM data to be used on last phase of suspend
+ * @sfrbu_regs: SFRBU registers mapping
* @bu: backup unit mapped data (for backup mode)
* @memcs: memory chip select
*/
@@ -62,6 +76,7 @@ struct at91_soc_pm {
const struct of_device_id *ws_ids;
struct at91_pm_bu *bu;
struct at91_pm_data data;
+ struct at91_pm_sfrbu_regs sfrbu_regs;
void *memcs;
};
@@ -356,9 +371,36 @@ static int at91_suspend_finish(unsigned long val)
return 0;
}
+static void at91_pm_switch_ba_to_vbat(void)
+{
+ unsigned int offset = offsetof(struct at91_pm_sfrbu_regs, pswbu);
+ unsigned int val;
+
+ /* Just for safety. */
+ if (!soc_pm.data.sfrbu)
+ return;
+
+ val = readl(soc_pm.data.sfrbu + offset);
+
+ /* Already on VBAT. */
+ if (!(val & soc_pm.sfrbu_regs.pswbu.state))
+ return;
+
+ val &= ~soc_pm.sfrbu_regs.pswbu.softsw;
+ val |= soc_pm.sfrbu_regs.pswbu.key | soc_pm.sfrbu_regs.pswbu.ctrl;
+ writel(val, soc_pm.data.sfrbu + offset);
+
+ /* Wait for update. */
+ val = readl(soc_pm.data.sfrbu + offset);
+ while (val & soc_pm.sfrbu_regs.pswbu.state)
+ val = readl(soc_pm.data.sfrbu + offset);
+}
+
static void at91_pm_suspend(suspend_state_t state)
{
if (soc_pm.data.mode == AT91_PM_BACKUP) {
+ at91_pm_switch_ba_to_vbat();
+
cpu_suspend(0, at91_suspend_finish);
/* The SRAM is lost between suspend cycles */
@@ -1155,6 +1197,11 @@ void __init sama5d2_pm_init(void)
soc_pm.ws_ids = sama5d2_ws_ids;
soc_pm.config_shdwc_ws = at91_sama5d2_config_shdwc_ws;
soc_pm.config_pmc_ws = at91_sama5d2_config_pmc_ws;
+
+ soc_pm.sfrbu_regs.pswbu.key = (0x4BD20C << 8);
+ soc_pm.sfrbu_regs.pswbu.ctrl = BIT(0);
+ soc_pm.sfrbu_regs.pswbu.softsw = BIT(1);
+ soc_pm.sfrbu_regs.pswbu.state = BIT(3);
}
void __init sama7_pm_init(void)
@@ -1185,6 +1232,11 @@ void __init sama7_pm_init(void)
soc_pm.ws_ids = sama7g5_ws_ids;
soc_pm.config_pmc_ws = at91_sam9x60_config_pmc_ws;
+
+ soc_pm.sfrbu_regs.pswbu.key = (0x4BD20C << 8);
+ soc_pm.sfrbu_regs.pswbu.ctrl = BIT(0);
+ soc_pm.sfrbu_regs.pswbu.softsw = BIT(1);
+ soc_pm.sfrbu_regs.pswbu.state = BIT(2);
}
static int __init at91_pm_modes_select(char *str)