[ARM] Kirkwood: clock gating for unused peripherals

To save power:

1. Enabling clock gating of unused peripherals

2. PLL and PHY of the units are also disabled (when possible.

Signed-off-by: Rabeeh Khoury <rabeeh@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>

arch/arm/mach-kirkwood/common.c

@@ -55,6 +55,13 @@ void __init kirkwood_map_io(void)
 	iotable_init(kirkwood_io_desc, ARRAY_SIZE(kirkwood_io_desc));
 }
 
+/*
+ * Default clock control bits.  Any bit _not_ set in this variable
+ * will be cleared from the hardware after platform devices have been
+ * registered.  Some reserved bits must be set to 1.
+ */
+unsigned int kirkwood_clk_ctrl = CGC_DUNIT | CGC_RESERVED;
+	
 
 /*****************************************************************************
  * EHCI
@@ -96,6 +103,7 @@ static struct platform_device kirkwood_ehci = {
 
 void __init kirkwood_ehci_init(void)
 {
+	kirkwood_clk_ctrl |= CGC_USB0;
 	platform_device_register(&kirkwood_ehci);
 }
 
@@ -152,6 +160,7 @@ static struct platform_device kirkwood_ge00 = {
 
 void __init kirkwood_ge00_init(struct mv643xx_eth_platform_data *eth_data)
 {
+	kirkwood_clk_ctrl |= CGC_GE0;
 	eth_data->shared = &kirkwood_ge00_shared;
 	kirkwood_ge00.dev.platform_data = eth_data;
 
@@ -213,6 +222,7 @@ static struct platform_device kirkwood_ge01 = {
 
 void __init kirkwood_ge01_init(struct mv643xx_eth_platform_data *eth_data)
 {
+	kirkwood_clk_ctrl |= CGC_GE1;
 	eth_data->shared = &kirkwood_ge01_shared;
 	kirkwood_ge01.dev.platform_data = eth_data;
 
@@ -287,6 +297,7 @@ static struct platform_device kirkwood_nand_flash = {
 void __init kirkwood_nand_init(struct mtd_partition *parts, int nr_parts,
 			       int chip_delay)
 {
+	kirkwood_clk_ctrl |= CGC_RUNIT;
 	kirkwood_nand_data.parts = parts;
 	kirkwood_nand_data.nr_parts = nr_parts;
 	kirkwood_nand_data.chip_delay = chip_delay;
@@ -338,6 +349,9 @@ static struct platform_device kirkwood_sata = {
 
 void __init kirkwood_sata_init(struct mv_sata_platform_data *sata_data)
 {
+	kirkwood_clk_ctrl |= CGC_SATA0;
+	if (sata_data->n_ports > 1)
+		kirkwood_clk_ctrl |= CGC_SATA1;
 	sata_data->dram = &kirkwood_mbus_dram_info;
 	kirkwood_sata.dev.platform_data = sata_data;
 	platform_device_register(&kirkwood_sata);
@@ -383,6 +397,7 @@ void __init kirkwood_sdio_init(struct mvsdio_platform_data *mvsdio_data)
 	else
 		mvsdio_data->clock = 200000000;
 	mvsdio_data->dram = &kirkwood_mbus_dram_info;
+	kirkwood_clk_ctrl |= CGC_SDIO;
 	kirkwood_sdio.dev.platform_data = mvsdio_data;
 	platform_device_register(&kirkwood_sdio);
 }
@@ -414,6 +429,7 @@ static struct platform_device kirkwood_spi = {
 
 void __init kirkwood_spi_init()
 {
+	kirkwood_clk_ctrl |= CGC_RUNIT;
 	platform_device_register(&kirkwood_spi);
 }
 
@@ -634,6 +650,7 @@ static struct platform_device kirkwood_xor01_channel = {
 
 static void __init kirkwood_xor0_init(void)
 {
+	kirkwood_clk_ctrl |= CGC_XOR0;
 	platform_device_register(&kirkwood_xor0_shared);
 
 	/*
@@ -732,6 +749,7 @@ static struct platform_device kirkwood_xor11_channel = {
 
 static void __init kirkwood_xor1_init(void)
 {
+	kirkwood_clk_ctrl |= CGC_XOR1;
 	platform_device_register(&kirkwood_xor1_shared);
 
 	/*
@@ -844,3 +862,44 @@ void __init kirkwood_init(void)
 	kirkwood_xor0_init();
 	kirkwood_xor1_init();
 }
+
+static int __init kirkwood_clock_gate(void)
+{
+	unsigned int curr = readl(CLOCK_GATING_CTRL);
+
+	printk(KERN_DEBUG "Gating clock of unused units\n");
+	printk(KERN_DEBUG "before: 0x%08x\n", curr);
+
+	/* Make sure those units are accessible */
+	writel(curr | CGC_SATA0 | CGC_SATA1 | CGC_PEX0, CLOCK_GATING_CTRL);
+
+	/* For SATA: first shutdown the phy */
+	if (!(kirkwood_clk_ctrl & CGC_SATA0)) {
+		/* Disable PLL and IVREF */
+		writel(readl(SATA0_PHY_MODE_2) & ~0xf, SATA0_PHY_MODE_2);
+		/* Disable PHY */
+		writel(readl(SATA0_IF_CTRL) | 0x200, SATA0_IF_CTRL);
+	}
+	if (!(kirkwood_clk_ctrl & CGC_SATA1)) {
+		/* Disable PLL and IVREF */
+		writel(readl(SATA1_PHY_MODE_2) & ~0xf, SATA1_PHY_MODE_2);
+		/* Disable PHY */
+		writel(readl(SATA1_IF_CTRL) | 0x200, SATA1_IF_CTRL);
+	}
+	
+	/* For PCIe: first shutdown the phy */
+	if (!(kirkwood_clk_ctrl & CGC_PEX0)) {
+		writel(readl(PCIE_LINK_CTRL) | 0x10, PCIE_LINK_CTRL);
+		while (1)
+			if (readl(PCIE_STATUS) & 0x1)
+				break;
+		writel(readl(PCIE_LINK_CTRL) & ~0x10, PCIE_LINK_CTRL);
+	}
+
+	/* Now gate clock the required units */
+	writel(kirkwood_clk_ctrl, CLOCK_GATING_CTRL);
+	printk(KERN_DEBUG " after: 0x%08x\n", readl(CLOCK_GATING_CTRL));
+
+	return 0;
+}
+late_initcall(kirkwood_clock_gate);

arch/arm/mach-kirkwood/include/mach/bridge-regs.h

@@ -39,4 +39,22 @@
 #define L2_CONFIG_REG		(BRIDGE_VIRT_BASE | 0x0128)
 #define L2_WRITETHROUGH		0x00000010
 
+#define CLOCK_GATING_CTRL	(BRIDGE_VIRT_BASE | 0x11c)
+#define CGC_GE0			(1 << 0)
+#define CGC_PEX0		(1 << 2)
+#define CGC_USB0		(1 << 3)
+#define CGC_SDIO		(1 << 4)
+#define CGC_TSU			(1 << 5)
+#define CGC_DUNIT		(1 << 6)
+#define CGC_RUNIT		(1 << 7)
+#define CGC_XOR0		(1 << 8)
+#define CGC_AUDIO		(1 << 9)
+#define CGC_SATA0		(1 << 14)
+#define CGC_SATA1		(1 << 15)
+#define CGC_XOR1		(1 << 16)
+#define CGC_CRYPTO		(1 << 17)
+#define CGC_GE1			(1 << 19)
+#define CGC_TDM			(1 << 20)
+#define CGC_RESERVED		((1 << 18) | (0x6 << 21))
+
 #endif

arch/arm/mach-kirkwood/include/mach/kirkwood.h

@@ -65,6 +65,8 @@
 #define BRIDGE_VIRT_BASE	(KIRKWOOD_REGS_VIRT_BASE | 0x20000)
 
 #define PCIE_VIRT_BASE		(KIRKWOOD_REGS_VIRT_BASE | 0x40000)
+#define PCIE_LINK_CTRL		(PCIE_VIRT_BASE | 0x70)
+#define PCIE_STATUS		(PCIE_VIRT_BASE | 0x1a04)
 
 #define USB_PHYS_BASE		(KIRKWOOD_REGS_PHYS_BASE | 0x50000)
 
@@ -81,6 +83,11 @@
 #define GE01_PHYS_BASE		(KIRKWOOD_REGS_PHYS_BASE | 0x74000)
 
 #define SATA_PHYS_BASE		(KIRKWOOD_REGS_PHYS_BASE | 0x80000)
+#define SATA_VIRT_BASE		(KIRKWOOD_REGS_VIRT_BASE | 0x80000)
+#define SATA0_IF_CTRL		(SATA_VIRT_BASE | 0x2050)
+#define SATA0_PHY_MODE_2	(SATA_VIRT_BASE | 0x2330)
+#define SATA1_IF_CTRL		(SATA_VIRT_BASE | 0x4050)
+#define SATA1_PHY_MODE_2	(SATA_VIRT_BASE | 0x4330)
 
 #define SDIO_PHYS_BASE		(KIRKWOOD_REGS_PHYS_BASE | 0x90000)
 

arch/arm/mach-kirkwood/pcie.c

@@ -14,6 +14,7 @@
 #include <asm/irq.h>
 #include <asm/mach/pci.h>
 #include <plat/pcie.h>
+#include <mach/bridge-regs.h>
 #include "common.h"
 
 
@@ -95,6 +96,7 @@ static struct pci_ops pcie_ops = {
 static int kirkwood_pcie_setup(int nr, struct pci_sys_data *sys)
 {
 	struct resource *res;
+	extern unsigned int kirkwood_clk_ctrl;
 
 	/*
 	 * Generic PCIe unit setup.
@@ -133,6 +135,8 @@ static int kirkwood_pcie_setup(int nr, struct pci_sys_data *sys)
 	sys->resource[2] = NULL;
 	sys->io_offset = 0;
 
+	kirkwood_clk_ctrl |= CGC_PEX0;
+
 	return 1;
 }