MLK-10774-1 imx: LDO: add LDO bypass

This patch is from two commits:
1.
748eac71fde78aa0c2e8cb3a3bab94bd994c06f5
ENGR00315499-5: Support i.MX6 1.2GHz via LDO bypass

Add check for 1.2GHz core speed. If Speed grading fuse is for 1.2GHz,
enable LDO bypass and setup PMIC voltages. LDO bypass is dependent
on the flatten device tree file.

2.
93d457e4c601ee5266bc30b7dfa5fa1bbfa8500a
MLK-9891-1: ARM: imx6: split WDOG_B setting from set_anatop_bypass() function

We set WDOG_B in set_anatop_bypass() before, because it is the only case, but now
on i.mx6sabreauto board, we didn't use ldo-bypass mode, but have to use WDOG_B to
reboot whole board, so split these code to independent function so that board file
can call it freely.

Board code is not included, board ldo bypass code will be in bsp update code.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>

4 files changed, 156 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c
index dd34138..0d1801c 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -18,6 +18,7 @@
 #include <asm/arch/sys_proto.h>
 #include <asm/imx-common/boot_mode.h>
 #include <asm/imx-common/dma.h>
+#include <libfdt.h>
 #include <stdbool.h>
 #include <asm/arch/mxc_hdmi.h>
 #include <asm/arch/crm_regs.h>
@@ -475,6 +476,147 @@ void s_init(void)
 	writel(mask528, &anatop->pfd_528_clr);
 }
 
+#ifdef CONFIG_LDO_BYPASS_CHECK
+DECLARE_GLOBAL_DATA_PTR;
+static int ldo_bypass;
+
+int check_ldo_bypass(void)
+{
+	const int *ldo_mode;
+	int node;
+
+	/* get the right fdt_blob from the global working_fdt */
+	gd->fdt_blob = working_fdt;
+	/* Get the node from FDT for anatop ldo-bypass */
+	node = fdt_node_offset_by_compatible(gd->fdt_blob, -1,
+		"fsl,imx6q-gpc");
+	if (node < 0) {
+		printf("No gpc device node %d, force to ldo-enable.\n", node);
+		return 0;
+	}
+	ldo_mode = fdt_getprop(gd->fdt_blob, node, "fsl,ldo-bypass", NULL);
+	/*
+	 * return 1 if "fsl,ldo-bypass = <1>", else return 0 if
+	 * "fsl,ldo-bypass = <0>" or no "fsl,ldo-bypass" property
+	 */
+	ldo_bypass = fdt32_to_cpu(*ldo_mode) == 1 ? 1 : 0;
+
+	return ldo_bypass;
+}
+
+int check_1_2G(void)
+{
+	u32 reg;
+	int result = 0;
+	struct ocotp_regs *ocotp = (struct ocotp_regs *)OCOTP_BASE_ADDR;
+	struct fuse_bank *bank = &ocotp->bank[0];
+	struct fuse_bank0_regs *fuse_bank0 =
+			(struct fuse_bank0_regs *)bank->fuse_regs;
+
+	reg = readl(&fuse_bank0->cfg3);
+	if (((reg >> 16) & 0x3) == 0x3) {
+		if (ldo_bypass) {
+			printf("Wrong dtb file used! i.MX6Q@1.2Ghz only "
+				"works with ldo-enable mode!\n");
+			/*
+			 * Currently, only imx6q-sabresd board might be here,
+			 * since only i.MX6Q support 1.2G and only Sabresd board
+			 * support ldo-bypass mode. So hardcode here.
+			 * You can also modify your board(i.MX6Q) dtb name if it
+			 * supports both ldo-bypass and ldo-enable mode.
+			 */
+			printf("Please use imx6q-sabresd-ldo.dtb!\n");
+			hang();
+		}
+		result = 1;
+	}
+
+	return result;
+}
+
+static int arm_orig_podf;
+void set_arm_freq_400M(bool is_400M)
+{
+	struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	if (is_400M)
+		writel(0x1, &mxc_ccm->cacrr);
+	else
+		writel(arm_orig_podf, &mxc_ccm->cacrr);
+}
+
+void prep_anatop_bypass(void)
+{
+	struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	arm_orig_podf = readl(&mxc_ccm->cacrr);
+	/*
+	 * Downgrade ARM speed to 400Mhz as half of boot 800Mhz before ldo
+	 * bypassed, also downgrade internal vddarm ldo to 0.975V.
+	 * VDDARM_IN 0.975V + 125mV = 1.1V < Max(1.3V)
+	 * otherwise at 800Mhz(i.mx6dl):
+	 * VDDARM_IN 1.175V + 125mV = 1.3V = Max(1.3V)
+	 * We need provide enough gap in this case.
+	 * skip if boot from 400M.
+	 */
+	if (!arm_orig_podf)
+		set_arm_freq_400M(true);
+#if !defined(CONFIG_MX6DL) && !defined(CONFIG_MX6SX)
+	set_ldo_voltage(LDO_ARM, 975);
+#else
+	set_ldo_voltage(LDO_ARM, 1150);
+#endif
+}
+
+void set_wdog_reset(struct wdog_regs *wdog)
+{
+	u32 reg = readw(&wdog->wcr);
+	/*
+	 * use WDOG_B mode to reset external pmic because it's risky for the
+	 * following watchdog reboot in case of cpu freq at lowest 400Mhz with
+	 * ldo-bypass mode. Because boot frequency maybe higher 800Mhz i.e. So
+	 * in ldo-bypass mode watchdog reset will only triger POR reset, not
+	 * WDOG reset. But below code depends on hardware design, if HW didn't
+	 * connect WDOG_B pin to external pmic such as i.mx6slevk, we can skip
+	 * these code since it assumed boot from 400Mhz always.
+	 */
+	reg = readw(&wdog->wcr);
+	reg |= 1 << 3;
+	/*
+	 * WDZST bit is write-once only bit. Align this bit in kernel,
+	 * otherwise kernel code will have no chance to set this bit.
+	 */
+	reg |= 1 << 0;
+	writew(reg, &wdog->wcr);
+}
+
+int set_anatop_bypass(int wdog_reset_pin)
+{
+	struct anatop_regs *anatop= (struct anatop_regs*)ANATOP_BASE_ADDR;
+	struct wdog_regs *wdog;
+	u32 reg = readl(&anatop->reg_core);
+
+	/* bypass VDDARM/VDDSOC */
+	reg = reg | (0x1F << 18) | 0x1F;
+	writel(reg, &anatop->reg_core);
+
+	if (wdog_reset_pin == 2)
+		wdog = (struct wdog_regs *) WDOG2_BASE_ADDR;
+	else if (wdog_reset_pin == 1)
+		wdog = (struct wdog_regs *) WDOG1_BASE_ADDR;
+	else
+		return arm_orig_podf;
+	set_wdog_reset(wdog);
+	return arm_orig_podf;
+}
+
+void finish_anatop_bypass(void)
+{
+	if (!arm_orig_podf)
+		set_arm_freq_400M(false);
+}
+#endif
+
 #ifdef CONFIG_IMX_HDMI
 void imx_enable_hdmi_phy(void)
 {
diff --git a/arch/arm/imx-common/cpu.c b/arch/arm/imx-common/cpu.c
index 067d08f..67c4197 100644
--- a/arch/arm/imx-common/cpu.c
+++ b/arch/arm/imx-common/cpu.c
@@ -218,6 +218,9 @@ void arch_preboot_os(void)
 	disable_sata_clock();
 #endif
 #endif
+#if defined(CONFIG_LDO_BYPASS_CHECK)
+	ldo_mode_set(check_ldo_bypass());
+#endif
 #if defined(CONFIG_VIDEO_IPUV3)
 	/* disable video before launching O/S */
 	ipuv3_fb_shutdown();
diff --git a/arch/arm/include/asm/arch-mx6/sys_proto.h b/arch/arm/include/asm/arch-mx6/sys_proto.h
index 28ba844..10bab2b 100644
--- a/arch/arm/include/asm/arch-mx6/sys_proto.h
+++ b/arch/arm/include/asm/arch-mx6/sys_proto.h
@@ -27,6 +27,16 @@ u32 get_cpu_rev(void);
 const char *get_imx_type(u32 imxtype);
 unsigned imx_ddr_size(void);
 void set_chipselect_size(int const);
+void set_wdog_reset(struct wdog_regs *wdog);
+
+#ifdef CONFIG_LDO_BYPASS_CHECK
+int check_ldo_bypass(void);
+int check_1_2G(void);
+int set_anatop_bypass(int wdog_reset_pin);
+void ldo_mode_set(int ldo_bypass);
+void prep_anatop_bypass(void);
+void finish_anatop_bypass(void);
+#endif
 
 /*
  * Initializes on-chip ethernet controllers.
diff --git a/include/configs/mx6_common.h b/include/configs/mx6_common.h
index e0528ce..b80a93d 100644
--- a/include/configs/mx6_common.h
+++ b/include/configs/mx6_common.h
@@ -22,6 +22,7 @@
 #define CONFIG_ARM_ERRATA_794072
 #define CONFIG_ARM_ERRATA_761320
 #define CONFIG_BOARD_POSTCLK_INIT
+#define CONFIG_LDO_BYPASS_CHECK
 
 #ifndef CONFIG_SYS_L2CACHE_OFF
 #define CONFIG_SYS_L2_PL310