ram: stm32mp1: the property st, phy-cal becomes optional

This parameter "st,phy-cal" becomes optional and when it is
absent the built-in PHY calibration is done.

It is the case in the helper dtsi file "stm32mp15-ddr.dtsi"
except if DDR_PHY_CAL_SKIP is defined.

This patch also impact the ddr interactive mode
- the registers of the param 'phy.cal' are initialized to 0 when
  "st,phy-cal" is not present in device tree (default behavior when
  DDR_PHY_CAL_SKIP is not activated)
- the info 'cal' field can be use to change the calibration behavior
  - cal=1 => use param phy.cal to initialize the PHY, built-in training
             is skipped
  - cal=0 => param phy.cal is absent, built-in training is used (default)

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>

arch/arm/dts/stm32mp15-ddr.dtsi

@@ -133,6 +133,7 @@
 				DDR_MR3
 			>;
 
+#ifdef DDR_PHY_CAL_SKIP
 			st,phy-cal = <
 				DDR_DX0DLLCR
 				DDR_DX0DQTR
@@ -148,6 +149,8 @@
 				DDR_DX3DQSTR
 			>;
 
+#endif
+
 			status = "okay";
 		};
 	};

doc/device-tree-bindings/memory-controllers/st,stm32mp1-ddr.txt

@@ -129,6 +129,8 @@ phyc attributes:
 		MR3
 
 - st,phy-cal	: phy cal depending of calibration or tuning of DDR
+	This parameter is optional; when it is absent the built-in PHY
+	calibration is done.
 	for STM32MP15x: 12 values are requested in this order
 		DX0DLLCR
 		DX0DQTR

drivers/ram/stm32mp1/stm32mp1_ddr.c

@@ -769,7 +769,8 @@ start:
  */
 	set_reg(priv, REGPHY_REG, &config->p_reg);
 	set_reg(priv, REGPHY_TIMING, &config->p_timing);
-	set_reg(priv, REGPHY_CAL, &config->p_cal);
+	if (config->p_cal_present)
+		set_reg(priv, REGPHY_CAL, &config->p_cal);
 
 	if (INTERACTIVE(STEP_PHY_INIT))
 		goto start;
@@ -804,13 +805,16 @@ start:
 
 	wait_operating_mode(priv, DDRCTRL_STAT_OPERATING_MODE_NORMAL);
 
-	debug("DDR DQS training : ");
+	if (config->p_cal_present) {
+		debug("DDR DQS training skipped.\n");
+	} else {
+		debug("DDR DQS training : ");
 /*  8. Disable Auto refresh and power down by setting
  *    - RFSHCTL3.dis_au_refresh = 1
  *    - PWRCTL.powerdown_en = 0
  *    - DFIMISC.dfiinit_complete_en = 0
  */
-	stm32mp1_refresh_disable(priv->ctl);
+		stm32mp1_refresh_disable(priv->ctl);
 
 /*  9. Program PUBL PGCR to enable refresh during training and rank to train
  *     not done => keep the programed value in PGCR
@@ -818,14 +822,15 @@ start:
 
 /* 10. configure PUBL PIR register to specify which training step to run */
 	/* warning : RVTRN  is not supported by this PUBL */
-	stm32mp1_ddrphy_init(priv->phy, DDRPHYC_PIR_QSTRN);
+		stm32mp1_ddrphy_init(priv->phy, DDRPHYC_PIR_QSTRN);
 
 /* 11. monitor PUB PGSR.IDONE to poll cpmpletion of training sequence */
-	ddrphy_idone_wait(priv->phy);
+		ddrphy_idone_wait(priv->phy);
 
 /* 12. set back registers in step 8 to the orginal values if desidered */
-	stm32mp1_refresh_restore(priv->ctl, config->c_reg.rfshctl3,
-				 config->c_reg.pwrctl);
+		stm32mp1_refresh_restore(priv->ctl, config->c_reg.rfshctl3,
+					 config->c_reg.pwrctl);
+	} /* if (config->p_cal_present) */
 
 	/* enable uMCTL2 AXI port 0 and 1 */
 	setbits_le32(&priv->ctl->pctrl_0, DDRCTRL_PCTRL_N_PORT_EN);

drivers/ram/stm32mp1/stm32mp1_ddr.h

@@ -170,6 +170,7 @@ struct stm32mp1_ddr_config {
 	struct stm32mp1_ddrphy_reg p_reg;
 	struct stm32mp1_ddrphy_timing p_timing;
 	struct stm32mp1_ddrphy_cal p_cal;
+	bool p_cal_present;
 };
 
 int stm32mp1_ddr_clk_enable(struct ddr_info *priv, u32 mem_speed);

drivers/ram/stm32mp1/stm32mp1_interactive.c

@@ -106,7 +106,7 @@ static void stm32mp1_do_usage(void)
 		"help                       displays help\n"
 		"info                       displays DDR information\n"
 		"info  <param> <val>        changes DDR information\n"
-		"      with <param> = step, name, size or speed\n"
+		"      with <param> = step, name, size, speed or cal\n"
 		"freq                       displays the DDR PHY frequency in kHz\n"
 		"freq  <freq>               changes the DDR PHY frequency\n"
 		"param [type|reg]           prints input parameters\n"
@@ -160,6 +160,7 @@ static void stm32mp1_do_info(struct ddr_info *priv,
 		printf("name = %s\n", config->info.name);
 		printf("size = 0x%x\n", config->info.size);
 		printf("speed = %d kHz\n", config->info.speed);
+		printf("cal = %d\n", config->p_cal_present);
 		return;
 	}
 
@@ -208,6 +209,16 @@ static void stm32mp1_do_info(struct ddr_info *priv,
 		}
 		return;
 	}
+	if (!strcmp(argv[1], "cal")) {
+		if (strict_strtoul(argv[2], 10, &value) < 0 ||
+		    (value != 0 && value != 1)) {
+			printf("invalid value %s\n", argv[2]);
+		} else {
+			config->p_cal_present = value;
+			printf("cal = %d\n", config->p_cal_present);
+		}
+		return;
+	}
 	printf("argument %s invalid\n", argv[1]);
 }
 

drivers/ram/stm32mp1/stm32mp1_ram.c

@@ -65,18 +65,22 @@ static __maybe_unused int stm32mp1_ddr_setup(struct udevice *dev)
 	struct clk axidcg;
 	struct stm32mp1_ddr_config config;
 
-#define PARAM(x, y) \
-	{ x,\
-	  offsetof(struct stm32mp1_ddr_config, y),\
-	  sizeof(config.y) / sizeof(u32)}
+#define PARAM(x, y, z)							\
+	{	.name = x,						\
+		.offset = offsetof(struct stm32mp1_ddr_config, y),	\
+		.size = sizeof(config.y) / sizeof(u32),			\
+		.present = z,						\
+	}
 
-#define CTL_PARAM(x) PARAM("st,ctl-"#x, c_##x)
-#define PHY_PARAM(x) PARAM("st,phy-"#x, p_##x)
+#define CTL_PARAM(x) PARAM("st,ctl-"#x, c_##x, NULL)
+#define PHY_PARAM(x) PARAM("st,phy-"#x, p_##x, NULL)
+#define PHY_PARAM_OPT(x) PARAM("st,phy-"#x, p_##x, &config.p_##x##_present)
 
 	const struct {
 		const char *name; /* name in DT */
 		const u32 offset; /* offset in config struct */
 		const u32 size;   /* size of parameters */
+		bool * const present;  /* presence indication for opt */
 	} param[] = {
 		CTL_PARAM(reg),
 		CTL_PARAM(timing),
@@ -84,7 +88,7 @@ static __maybe_unused int stm32mp1_ddr_setup(struct udevice *dev)
 		CTL_PARAM(perf),
 		PHY_PARAM(reg),
 		PHY_PARAM(timing),
-		PHY_PARAM(cal)
+		PHY_PARAM_OPT(cal)
 	};
 
 	config.info.speed = dev_read_u32_default(dev, "st,mem-speed", 0);
@@ -103,11 +107,25 @@ static __maybe_unused int stm32mp1_ddr_setup(struct udevice *dev)
 					 param[idx].size);
 		debug("%s: %s[0x%x] = %d\n", __func__,
 		      param[idx].name, param[idx].size, ret);
-		if (ret) {
+		if (ret &&
+		    (ret != -FDT_ERR_NOTFOUND || !param[idx].present)) {
 			pr_err("%s: Cannot read %s, error=%d\n",
 			       __func__, param[idx].name, ret);
 			return -EINVAL;
 		}
+		if (param[idx].present) {
+			/* save presence of optional parameters */
+			*param[idx].present = true;
+			if (ret == -FDT_ERR_NOTFOUND) {
+				*param[idx].present = false;
+#ifdef CONFIG_STM32MP1_DDR_INTERACTIVE
+				/* reset values if used later */
+				memset((void *)((u32)&config +
+						param[idx].offset),
+					0, param[idx].size * sizeof(u32));
+#endif
+			}
+		}
 	}
 
 	ret = clk_get_by_name(dev, "axidcg", &axidcg);