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authorClaudiu Beznea <claudiu.beznea@microchip.com>2022-01-13 17:48:54 +0300
committerNicolas Ferre <nicolas.ferre@microchip.com>2022-02-25 14:36:25 +0300
commit9584e7263e9ebcd94b184dc3efc847355a624220 (patch)
tree9c1c07f2a65d6329d072f7fcfe0965b865f282d6 /arch/arm/mach-at91
parent9a0775c9cd3d89d1fe957a137131681a33f5736b (diff)
downloadlinux-9584e7263e9ebcd94b184dc3efc847355a624220.tar.xz
ARM: at91: PM: add cpu idle support for sama7g5
Add CPU idle support for SAMA7G5. Support will make use of PMC_CPU_RATIO register to divide the CPU clock by 16 before switching it to idle and use automatic self-refresh option of DDR controller. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Acked-by: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Link: https://lore.kernel.org/r/20220113144900.906370-5-claudiu.beznea@microchip.com
Diffstat (limited to 'arch/arm/mach-at91')
-rw-r--r--arch/arm/mach-at91/pm.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index dd6f4ce3f766..0fd609e26615 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -605,6 +605,30 @@ static void at91sam9_sdram_standby(void)
at91_ramc_write(1, AT91_SDRAMC_LPR, saved_lpr1);
}
+static void sama7g5_standby(void)
+{
+ int pwrtmg, ratio;
+
+ pwrtmg = readl(soc_pm.data.ramc[0] + UDDRC_PWRCTL);
+ ratio = readl(soc_pm.data.pmc + AT91_PMC_RATIO);
+
+ /*
+ * Place RAM into self-refresh after a maximum idle clocks. The maximum
+ * idle clocks is configured by bootloader in
+ * UDDRC_PWRMGT.SELFREF_TO_X32.
+ */
+ writel(pwrtmg | UDDRC_PWRCTL_SELFREF_EN,
+ soc_pm.data.ramc[0] + UDDRC_PWRCTL);
+ /* Divide CPU clock by 16. */
+ writel(ratio & ~AT91_PMC_RATIO_RATIO, soc_pm.data.pmc + AT91_PMC_RATIO);
+
+ cpu_do_idle();
+
+ /* Restore previous configuration. */
+ writel(ratio, soc_pm.data.pmc + AT91_PMC_RATIO);
+ writel(pwrtmg, soc_pm.data.ramc[0] + UDDRC_PWRCTL);
+}
+
struct ramc_info {
void (*idle)(void);
unsigned int memctrl;
@@ -615,6 +639,7 @@ static const struct ramc_info ramc_infos[] __initconst = {
{ .idle = at91sam9_sdram_standby, .memctrl = AT91_MEMCTRL_SDRAMC},
{ .idle = at91_ddr_standby, .memctrl = AT91_MEMCTRL_DDRSDR},
{ .idle = sama5d3_ddr_standby, .memctrl = AT91_MEMCTRL_DDRSDR},
+ { .idle = sama7g5_standby, },
};
static const struct of_device_id ramc_ids[] __initconst = {
@@ -622,7 +647,7 @@ static const struct of_device_id ramc_ids[] __initconst = {
{ .compatible = "atmel,at91sam9260-sdramc", .data = &ramc_infos[1] },
{ .compatible = "atmel,at91sam9g45-ddramc", .data = &ramc_infos[2] },
{ .compatible = "atmel,sama5d3-ddramc", .data = &ramc_infos[3] },
- { .compatible = "microchip,sama7g5-uddrc", },
+ { .compatible = "microchip,sama7g5-uddrc", .data = &ramc_infos[4], },
{ /*sentinel*/ }
};