ram: stm32mp1: Unconditionally enable ASR

Enable DRAM ASR, auto self-refresh, unconditionally. This saves non-trivial
amount of power both at runtime and in suspend (on 2x W632GU6NB-15 ~150mW).

Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>

diff --git a/drivers/ram/stm32mp1/stm32mp1_ddr.c b/drivers/ram/stm32mp1/stm32mp1_ddr.c
index 4d78aa5..528a171 100644 (file)
--- a/drivers/ram/stm32mp1/stm32mp1_ddr.c
+++ b/drivers/ram/stm32mp1/stm32mp1_ddr.c
@@ -27,6 +27,8 @@
 #define RCC_DDRITFCR_DPHYAPBRST                (BIT(17))
 #define RCC_DDRITFCR_DPHYRST           (BIT(18))
 #define RCC_DDRITFCR_DPHYCTLRST                (BIT(19))
+#define RCC_DDRITFCR_DDRCKMOD_MASK     GENMASK(22, 20)
+#define RCC_DDRITFCR_DDRCKMOD_ASR      BIT(20)
 
 struct reg_desc {
        const char *name;
@@ -651,6 +653,26 @@ static void stm32mp1_refresh_restore(struct stm32mp1_ddrctl *ctl,
        wait_sw_done_ack(ctl);
 }
 
+static void stm32mp1_asr_enable(struct ddr_info *priv)
+{
+       struct stm32mp1_ddrctl *ctl = priv->ctl;
+
+       clrsetbits_le32(priv->rcc + RCC_DDRITFCR, RCC_DDRITFCR_DDRCKMOD_MASK,
+                       RCC_DDRITFCR_DDRCKMOD_ASR);
+
+       start_sw_done(ctl);
+
+       setbits_le32(&ctl->hwlpctl, DDRCTRL_HWLPCTL_HW_LP_EN);
+       writel(DDRCTRL_PWRTMG_POWERDOWN_TO_X32(0x10) |
+              DDRCTRL_PWRTMG_SELFREF_TO_X32(0x01),
+              &ctl->pwrtmg);
+       setbits_le32(&ctl->pwrctl, DDRCTRL_PWRCTL_EN_DFI_DRAM_CLK_DISABLE);
+       setbits_le32(&ctl->pwrctl, DDRCTRL_PWRCTL_SELFREF_EN);
+
+       setbits_le32(&ctl->dfimisc, DDRCTRL_DFIMISC_DFI_INIT_COMPLETE_EN);
+       wait_sw_done_ack(ctl);
+}
+
 /* board-specific DDR power initializations. */
 __weak int board_ddr_power_init(enum ddr_type ddr_type)
 {
@@ -822,6 +844,9 @@ start:
        stm32mp1_refresh_restore(priv->ctl, config->c_reg.rfshctl3,
                                 config->c_reg.pwrctl);
 
+/* Enable auto-self-refresh, which saves a bit of power at runtime. */
+       stm32mp1_asr_enable(priv);
+
        /* enable uMCTL2 AXI port 0 and 1 */
        setbits_le32(&priv->ctl->pctrl_0, DDRCTRL_PCTRL_N_PORT_EN);
        setbits_le32(&priv->ctl->pctrl_1, DDRCTRL_PCTRL_N_PORT_EN);

diff --git a/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h b/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
index f1a26e3..42be1ba 100644 (file)
--- a/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
+++ b/drivers/ram/stm32mp1/stm32mp1_ddr_regs.h
@@ -265,8 +265,14 @@ struct stm32mp1_ddrphy {
 
 #define DDRCTRL_PWRCTL_SELFREF_EN              BIT(0)
 #define DDRCTRL_PWRCTL_POWERDOWN_EN            BIT(1)
+#define DDRCTRL_PWRCTL_EN_DFI_DRAM_CLK_DISABLE BIT(3)
 #define DDRCTRL_PWRCTL_SELFREF_SW              BIT(5)
 
+#define DDRCTRL_PWRTMG_SELFREF_TO_X32(n)       (((n) & 0xff) << 16)
+#define DDRCTRL_PWRTMG_POWERDOWN_TO_X32(n)     ((n) & 0x1f)
+
+#define DDRCTRL_HWLPCTL_HW_LP_EN               BIT(0)
+
 #define DDRCTRL_RFSHCTL3_DIS_AUTO_REFRESH      BIT(0)
 
 #define DDRCTRL_RFSHTMG_T_RFC_NOM_X1_X32_MASK  GENMASK(27, 16)