ARM: 5964/1: ux500: support clock gating

Implement clock gating support for the u8500 clocks.

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 125 insertions, 0 deletions

diff --git a/arch/arm/mach-ux500/clock.h b/arch/arm/mach-ux500/clock.h
new file mode 100644
index 00000000000..e4f99b65026
--- /dev/null
+++ b/arch/arm/mach-ux500/clock.h
@@ -0,0 +1,125 @@
+/*
+ *  Copyright (C) 2010 ST-Ericsson
+ *  Copyright (C) 2009 STMicroelectronics
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/**
+ * struct clkops - ux500 clock operations
+ * @enable:	function to enable the clock
+ * @disable:	function to disable the clock
+ * @get_rate:	function to get the current clock rate
+ *
+ * This structure contains function pointers to functions that will be used to
+ * control the clock.  All of these functions are optional.  If get_rate is
+ * NULL, the rate in the struct clk will be used.
+ */
+struct clkops {
+	void (*enable) (struct clk *);
+	void (*disable) (struct clk *);
+	unsigned long (*get_rate) (struct clk *);
+};
+
+/**
+ * struct clk - ux500 clock structure
+ * @ops:		pointer to clkops struct used to control this clock
+ * @name:		name, for debugging
+ * @enabled:		refcount. positive if enabled, zero if disabled
+ * @rate:		fixed rate for clocks which don't implement
+ * 			ops->getrate
+ * @prcmu_cg_off:	address offset of the combined enable/disable register
+ * 			(used on u8500v1)
+ * @prcmu_cg_bit:	bit in the combined enable/disable register (used on
+ * 			u8500v1)
+ * @prcmu_cg_mgt:	address of the enable/disable register (used on
+ * 			u8500ed)
+ * @cluster:		peripheral cluster number
+ * @prcc_bus:		bit for the bus clock in the peripheral's CLKRST
+ * @prcc_kernel:	bit for the kernel clock in the peripheral's CLKRST.
+ * 			-1 if no kernel clock exists.
+ * @parent_cluster:	pointer to parent's cluster clk struct
+ * @parent_periph:	pointer to parent's peripheral clk struct
+ *
+ * Peripherals are organised into clusters, and each cluster has an associated
+ * bus clock.  Some peripherals also have a parent peripheral clock.
+ *
+ * In order to enable a clock for a peripheral, we need to enable:
+ * 	(1) the parent cluster (bus) clock at the PRCMU level
+ * 	(2) the parent peripheral clock (if any) at the PRCMU level
+ * 	(3) the peripheral's bus & kernel clock at the PRCC level
+ *
+ * (1) and (2) are handled by defining clk structs (DEFINE_PRCMU_CLK) for each
+ * of the cluster and peripheral clocks, and hooking these as the parents of
+ * the individual peripheral clocks.
+ *
+ * (3) is handled by specifying the bits in the PRCC control registers required
+ * to enable these clocks and modifying them in the ->enable and
+ * ->disable callbacks of the peripheral clocks (DEFINE_PRCC_CLK).
+ *
+ * This structure describes both the PRCMU-level clocks and PRCC-level clocks.
+ * The prcmu_* fields are only used for the PRCMU clocks, and the cluster,
+ * prcc, and parent pointers are only used for the PRCC-level clocks.
+ */
+struct clk {
+	const struct clkops	*ops;
+	const char 		*name;
+	unsigned int		enabled;
+
+	unsigned long		rate;
+	struct list_head	list;
+
+	/* These three are only for PRCMU clks */
+
+	unsigned int		prcmu_cg_off;
+	unsigned int		prcmu_cg_bit;
+	unsigned int		prcmu_cg_mgt;
+
+	/* The rest are only for PRCC clks */
+
+	int			cluster;
+	unsigned int		prcc_bus;
+	unsigned int		prcc_kernel;
+
+	struct clk		*parent_cluster;
+	struct clk		*parent_periph;
+};
+
+#define DEFINE_PRCMU_CLK(_name, _cg_off, _cg_bit, _reg)		\
+struct clk clk_##_name = {					\
+		.name		= #_name,			\
+		.ops    	= &clk_prcmu_ops, 		\
+		.prcmu_cg_off	= _cg_off, 			\
+		.prcmu_cg_bit	= _cg_bit,			\
+		.prcmu_cg_mgt	= PRCM_##_reg##_MGT		\
+	}
+
+#define DEFINE_PRCMU_CLK_RATE(_name, _cg_off, _cg_bit, _reg, _rate)	\
+struct clk clk_##_name = {						\
+		.name		= #_name,				\
+		.ops    	= &clk_prcmu_ops, 			\
+		.prcmu_cg_off	= _cg_off, 				\
+		.prcmu_cg_bit	= _cg_bit,				\
+		.rate		= _rate,				\
+		.prcmu_cg_mgt	= PRCM_##_reg##_MGT			\
+	}
+
+#define DEFINE_PRCC_CLK(_pclust, _name, _bus_en, _kernel_en, _kernclk)	\
+struct clk clk_##_name = {						\
+		.name		= #_name,				\
+		.ops    	= &clk_prcc_ops, 			\
+		.cluster 	= _pclust,				\
+		.prcc_bus 	= _bus_en, 				\
+		.prcc_kernel 	= _kernel_en, 				\
+		.parent_cluster = &clk_per##_pclust##clk,		\
+		.parent_periph 	= _kernclk				\
+	}
+
+#define CLK(_clk, _devname, _conname)			\
+	{						\
+		.clk	= &clk_##_clk,			\
+		.dev_id	= _devname,			\
+		.con_id = _conname,			\
+	}