mach-ux500: backport clock rate callbacks and MTU frequency fix

This is a backport of the changes adding per-clock callbacks
submitted to the mainline kernel tree, and reads out the MTU-
specific clock routing register.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/1700
Signed-off-by: Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
Change-Id: I41f65d78b995ecfa210b9bf6283351b027ae8bbd
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/2631
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

3 files changed, 116 insertions, 4 deletions

diff --git a/arch/arm/mach-ux500/clock.c b/arch/arm/mach-ux500/clock.c
index 24561b35ee7..43d6b9e2062 100755
--- a/arch/arm/mach-ux500/clock.c
+++ b/arch/arm/mach-ux500/clock.c
@@ -60,6 +60,9 @@
 #define PRCM_DMACLK_MGT		0x074
 #define PRCM_B2R2CLK_MGT	0x078
 #define PRCM_TVCLK_MGT		0x07C
+#define PRCM_TCR		0x1C8
+#define PRCM_TCR_STOPPED	(1 << 16)
+#define PRCM_TCR_DOZE_MODE	(1 << 17)
 #define PRCM_UNIPROCLK_MGT	0x278
 #define PRCM_SSPCLK_MGT		0x280
 #define PRCM_RNGCLK_MGT		0x284
@@ -141,10 +144,95 @@ void clk_disable(struct clk *clk)
 }
 EXPORT_SYMBOL(clk_disable);
 
+/*
+ * The MTU has a separate, rather complex muxing setup
+ * with alternative parents (peripheral cluster or
+ * ULP or fixed 32768 Hz) depending on settings
+ */
+static unsigned long clk_mtu_get_rate(struct clk *clk)
+{
+	void __iomem *addr = __io_address(UX500_PRCMU_BASE)
+		+ PRCM_TCR;
+	u32 tcr = readl(addr);
+	int mtu = (int) clk->data;
+	/*
+	 * One of these is selected eventually
+	 * TODO: Replace the constant with a reference
+	 * to the ULP source once this is modeled.
+	 */
+	unsigned long clk32k = 32768;
+	unsigned long mturate;
+	unsigned long retclk;
+
+	/* Get the rate from the parent as a default */
+	if (clk->parent_periph)
+		mturate = clk_get_rate(clk->parent_periph);
+	else if (clk->parent_cluster)
+		mturate = clk_get_rate(clk->parent_cluster);
+	else
+		/* We need to be connected SOMEWHERE */
+		BUG();
+
+	/*
+	 * Are we in doze mode?
+	 * In this mode the parent peripheral or the fixed 32768 Hz
+	 * clock is fed into the block.
+	 */
+	if (!(tcr & PRCM_TCR_DOZE_MODE)) {
+		/*
+		 * Here we're using the clock input from the APE ULP
+		 * clock domain. But first: are the timers stopped?
+		 */
+		if (tcr & PRCM_TCR_STOPPED) {
+			clk32k = 0;
+			mturate = 0;
+		} else {
+			/* Else default mode: 0 and 2.4 MHz */
+			clk32k = 0;
+			if (cpu_is_u5500())
+				/* DB5500 divides by 8 */
+				mturate /= 8;
+			else if (cpu_is_u8500ed()) {
+				/*
+				 * This clocking setting must not be used
+				 * in the ED chip, it is simply not
+				 * connected anywhere!
+				 */
+				mturate = 0;
+				BUG();
+			} else
+				/*
+				 * In this mode the ulp38m4 clock is divided
+				 * by a factor 16, on the DB8500 typically
+				 * 38400000 / 16 ~ 2.4 MHz.
+				 * TODO: Replace the constant with a reference
+				 * to the ULP source once this is modeled.
+				 */
+				mturate = 38400000 / 16;
+		}
+	}
+
+	/* Return the clock selected for this MTU */
+	if (tcr & (1 << mtu))
+		retclk = clk32k;
+	else
+		retclk = mturate;
+
+	pr_info("MTU%d clock rate: %lu Hz\n", mtu, retclk);
+	return retclk;
+}
+
 unsigned long clk_get_rate(struct clk *clk)
 {
 	unsigned long rate;
 
+	/*
+	 * If there is a custom getrate callback for this clock,
+	 * it will take precedence.
+	 */
+	if (clk->get_rate)
+		return clk->get_rate(clk);
+
 	if (clk->ops && clk->ops->get_rate)
 		return clk->ops->get_rate(clk);
 
@@ -385,8 +473,9 @@ static DEFINE_PRCC_CLK(5, usb_v1, 	0,  0, NULL);
 
 /* Peripheral Cluster #6 */
 
-static DEFINE_PRCC_CLK(6, mtu1_v1, 	8, -1, NULL);
-static DEFINE_PRCC_CLK(6, mtu0_v1, 	7, -1, NULL);
+/* MTU ID in data */
+static DEFINE_PRCC_CLK_CUSTOM(6, mtu1_v1, 8, -1, NULL, clk_mtu_get_rate, 1);
+static DEFINE_PRCC_CLK_CUSTOM(6, mtu0_v1, 7, -1, NULL, clk_mtu_get_rate, 0);
 static DEFINE_PRCC_CLK(6, cfgreg_v1, 	6,  6, NULL);
 static DEFINE_PRCC_CLK(6, dmc_ed, 	6,  6, NULL);
 static DEFINE_PRCC_CLK(6, hash1, 	5, -1, NULL);
@@ -401,8 +490,9 @@ static DEFINE_PRCC_CLK(6, rng_v1, 	0,  0, &clk_rngclk);
 /* Peripheral Cluster #7 */
 
 static DEFINE_PRCC_CLK(7, tzpc0_ed, 	4, -1, NULL);
-static DEFINE_PRCC_CLK(7, mtu1_ed, 	3, -1, NULL);
-static DEFINE_PRCC_CLK(7, mtu0_ed, 	2, -1, NULL);
+/* MTU ID in data */
+static DEFINE_PRCC_CLK_CUSTOM(7, mtu1_ed, 3, -1, NULL, clk_mtu_get_rate, 1);
+static DEFINE_PRCC_CLK_CUSTOM(7, mtu0_ed, 2, -1, NULL, clk_mtu_get_rate, 0);
 static DEFINE_PRCC_CLK(7, wdg_ed, 	1, -1, NULL);
 static DEFINE_PRCC_CLK(7, cfgreg_ed, 	0, -1, NULL);
 
@@ -677,6 +767,7 @@ int __init clk_init(void)
 		clk_prcmu_ops.enable = clk_prcmu_ed_enable;
 		clk_prcmu_ops.disable = clk_prcmu_ed_disable;
 		clk_i2cclk.rate = 48000000;
+		clk_per6clk.rate = 100000000;
 	} else if (cpu_is_u8500v1()) {
 		void __iomem *sdmmclkmgt = __io_address(U8500_PRCMU_BASE)
 					   + PRCM_SDMMCCLK_MGT;
@@ -691,6 +782,7 @@ int __init clk_init(void)
 		clk_prcmu_ops.disable = NULL;
 		clk_prcc_ops.enable = NULL;
 		clk_prcc_ops.disable = NULL;
+		clk_per6clk.rate = 26000000;
 	}
 
 	clks_register(u8500_common_clkregs, ARRAY_SIZE(u8500_common_clkregs));
diff --git a/arch/arm/mach-ux500/clock.h b/arch/arm/mach-ux500/clock.h
index 50383fb028d..5a454b95886 100755
--- a/arch/arm/mach-ux500/clock.h
+++ b/arch/arm/mach-ux500/clock.h
@@ -51,6 +51,9 @@ struct clkops {
  * @ops:		pointer to clkops struct used to control this clock
  * @name:		name, for debugging
  * @enabled:		refcount. positive if enabled, zero if disabled
+ * @get_rate:		custom callback for getting the clock rate
+ * @data:		custom per-clock data for example for the get_rate
+ *			callback
  * @rate:		fixed rate for clocks which don't implement
  * 			ops->getrate
  * @prcmu_cg_off:	address offset of the combined enable/disable register
@@ -90,6 +93,8 @@ struct clk {
 	const struct clkops	*ops;
 	const char 		*name;
 	unsigned int		enabled;
+	unsigned long		(*get_rate)(struct clk *);
+	void			*data;
 
 	unsigned long		rate;
 	struct list_head	list;
@@ -159,6 +164,20 @@ struct clk clk_##_name = {						\
 		.parent_periph 	= _kernclk				\
 	}
 
+#define DEFINE_PRCC_CLK_CUSTOM(_pclust, _name, _bus_en, _kernel_en, _kernclk, _callback, _data) \
+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,				\
+		.get_rate	= _callback,				\
+		.data		= (void *) _data			\
+	}
+
+
 #define CLK(_clk, _devname, _conname)			\
 	{						\
 		.clk	= &clk_##_clk,			\
diff --git a/arch/arm/mach-ux500/cpu-db5500.c b/arch/arm/mach-ux500/cpu-db5500.c
index c9844c9d86c..6bf35781d40 100644
--- a/arch/arm/mach-ux500/cpu-db5500.c
+++ b/arch/arm/mach-ux500/cpu-db5500.c
@@ -23,6 +23,7 @@ static struct map_desc u5500_io_desc[] __initdata = {
 	__IO_DEV_DESC(U5500_GPIO2_BASE, SZ_4K),
 	__IO_DEV_DESC(U5500_GPIO3_BASE, SZ_4K),
 	__IO_DEV_DESC(U5500_GPIO4_BASE, SZ_4K),
+	__IO_DEV_DESC(U5500_PRCMU_BASE, SZ_4K),
 };
 
 static struct resource mbox0_resources[] = {