[U-Boot] [PATCH 6/6] mx6: soc: Disable VDDPU regulator

[Ranjani.Vaidyanathan at freescale.com]

Hi Fabio,

The PU power-up/power-down sequence has specific steps, includes some clock management. Please refer to the kernel code for the sequence.

Thanks,
Ranjani

-----Original Message-----
From: Fabio Estevam [mailto:festevam at gmail.com] 
Sent: Wednesday, December 18, 2013 9:16 PM
To: sbabic at denx.de
Cc: Huang Yongcai-B20788; Liu Hui-R64343; Vaidyanathan Ranjani-RA5478; eric.nelson at boundarydevices.com; troy.kisky at boundarydevices.com; u-boot at lists.denx.de; Estevam Fabio-R49496
Subject: [PATCH 6/6] mx6: soc: Disable VDDPU regulator

From: Fabio Estevam <fabio.estevam at freescale.com>

As U-boot does not use GPU/VPU peripherals, shutdown the VDDPU regulator in order to save power.

Signed-off-by: Anson Huang <b20788 at freescale.com>
Signed-off-by: Jason Liu <r64343 at freescale.com>
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
---
 arch/arm/cpu/armv7/mx6/soc.c             | 23 +++++++++++++++++++++++
 arch/arm/include/asm/arch-mx6/imx-regs.h | 23 +++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/arch/arm/cpu/armv7/mx6/soc.c b/arch/arm/cpu/armv7/mx6/soc.c index 9dc30ba..243226e 100644
--- a/arch/arm/cpu/armv7/mx6/soc.c
+++ b/arch/arm/cpu/armv7/mx6/soc.c
@@ -19,6 +19,8 @@
 #include <asm/arch/mxc_hdmi.h>
 #include <asm/arch/crm_regs.h>
 
+#define VDDPU_MASK	(0x1f << 9)
+
 enum ldo_reg {
 	LDO_ARM,
 	LDO_SOC,
@@ -177,11 +179,32 @@ static void imx_set_wdog_powerdown(bool enable)
 	writew(enable, &wdog2->wmcr);
 }
 
+static void imx_set_vddpu_power_down(void) {
+	struct anatop_regs *anatop = (struct anatop_regs *)ANATOP_BASE_ADDR;
+	struct gpc_regs *gpc = (struct gpc_regs *)GPC_BASE_ADDR;
+
+	u32 val;
+
+	/* need to power down xPU in GPC before turning off PU LDO */
+	val = readl(&gpc->gpu_ctrl);
+	writel(val | 0x1, &gpc->gpu_ctrl);
+
+	val = readl(&gpc->ctrl);
+	writel(val | 0x1, &gpc->ctrl);
+	while (readl(&gpc->ctrl) & 0x1)
+		;
+
+	/* disable VDDPU */
+	writel(VDDPU_MASK, &anatop->reg_core_clr); }
+
 int arch_cpu_init(void)
 {
 	init_aips();
 
 	imx_set_wdog_powerdown(false); /* Disable PDE bit of WMCR register */
+	imx_set_vddpu_power_down();
 
 #ifdef CONFIG_APBH_DMA
 	/* Start APBH DMA */
diff --git a/arch/arm/include/asm/arch-mx6/imx-regs.h b/arch/arm/include/asm/arch-mx6/imx-regs.h
index 7ef7152..fb0c4c7 100644
--- a/arch/arm/include/asm/arch-mx6/imx-regs.h
+++ b/arch/arm/include/asm/arch-mx6/imx-regs.h
@@ -659,5 +659,28 @@ struct wdog_regs {
 	u16	wmcr;	/* Miscellaneous Control */
 };
 
+struct gpc_regs {
+	u32	ctrl;		/* 0x000 */
+	u32	pgr;		/* 0x004 */
+	u32	imr1;		/* 0x008 */
+	u32	imr2;		/* 0x00c */
+	u32	imr3;		/* 0x010 */
+	u32	imr4;		/* 0x014 */
+	u32	isr1;		/* 0x018 */
+	u32	isr2;		/* 0x01c */
+	u32	isr3;		/* 0x020 */
+	u32	isr4;		/* 0x024 */
+	u32	reserved1[0x86];
+	u32	gpu_ctrl;	/* 0x260 */
+	u32	gpu_pupscr;	/* 0x264 */
+	u32	gpu_pdnscr;	/* 0x268 */
+	u32	gpu_sr;		/* 0x26c */
+	u32	reserved2[0xc];
+	u32	cpu_ctrl;	/* 0x2a0 */
+	u32	cpu_pupscr;	/* 0x2a4 */
+	u32	cpu_pdnscr;	/* 0x2a8 */
+	u32	cpu_sr;		/* 0x2ac */
+};
+
 #endif /* __ASSEMBLER__*/
 #endif /* __ASM_ARCH_MX6_IMX_REGS_H__ */
--
1.8.1.2