To use self-refresh mode for DDR3 SDRAM memory in LPSTOPx mode, the hardware need to have pull-ups/downs populated on RESET/CKE line of the DDR memory. Read the device tree property which indicates whether a given board has such resistors populated.
Signed-off-by: Stefan Agner <[email protected]> --- arch/arm/mach-imx/pm-vf610.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-imx/pm-vf610.c b/arch/arm/mach-imx/pm-vf610.c index ecc7c9c..3da93e9 100644 --- a/arch/arm/mach-imx/pm-vf610.c +++ b/arch/arm/mach-imx/pm-vf610.c @@ -93,6 +93,7 @@ static void __iomem *suspend_ocram_base; static void (*vf610_suspend_in_ocram_fn)(void __iomem *ocram_vbase); +static bool has_cke_reset_pulls; #ifdef DEBUG static void __iomem *uart_membase; @@ -382,7 +383,8 @@ static int vf610_pm_enter(suspend_state_t state) static int vf610_pm_valid(suspend_state_t state) { - return (state == PM_SUSPEND_STANDBY || state == PM_SUSPEND_MEM); + return (state == PM_SUSPEND_STANDBY || + (state == PM_SUSPEND_MEM && has_cke_reset_pulls)); } static const struct platform_suspend_ops vf610_pm_ops = { @@ -476,6 +478,19 @@ static int __init vf610_suspend_init(const struct vf610_pm_socdata *socdata) return ret; #endif + node = of_find_compatible_node(NULL, NULL, socdata->ddrmc_compat); + if (node) { + has_cke_reset_pulls = + of_property_read_bool(node, "fsl,has-cke-reset-pulls"); + + of_node_put(node); + } + + if (has_cke_reset_pulls) + pr_info("PM: CKE/RESET pulls available, enable Suspend-to-RAM\n"); + else + pr_info("PM: No CKE/RESET pulls, disable Suspend-to-RAM\n"); + suspend_set_ops(&vf610_pm_ops); node = of_find_compatible_node(NULL, NULL, "mmio-sram"); -- 2.7.2
