[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>

1 files changed, 59 insertions, 0 deletions

diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
index 6e3eb1a6a660..d127731f47dc 100644
--- a/arch/arm/mach-kirkwood/common.c
+++ b/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);