ARM: Tegra: Add smp_twd clock for Tegra20

Clockevent's frequency is changed upon cpufreq change
notification. It fetches local timer's rate to update the
clockevent frequency. This patch adds local timer clock
for Tegra20.

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/tegra20_clocks.c

@@ -376,6 +376,25 @@ struct clk_ops tegra_super_ops = {
 	.recalc_rate = tegra20_super_clk_recalc_rate,
 };
 
+static unsigned long tegra20_twd_clk_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct clk_tegra *c = to_clk_tegra(hw);
+	u64 rate = parent_rate;
+
+	if (c->mul != 0 && c->div != 0) {
+		rate *= c->mul;
+		rate += c->div - 1; /* round up */
+		do_div(rate, c->div);
+	}
+
+	return rate;
+}
+
+struct clk_ops tegra_twd_ops = {
+	.recalc_rate = tegra20_twd_clk_recalc_rate,
+};
+
 static u8 tegra20_cop_clk_get_parent(struct clk_hw *hw)
 {
 	return 0;

arch/arm/mach-tegra/tegra20_clocks.h

@@ -28,6 +28,7 @@ extern struct clk_ops tegra_cdev_clk_ops;
 extern struct clk_ops tegra_audio_sync_clk_ops;
 extern struct clk_ops tegra_super_ops;
 extern struct clk_ops tegra_cpu_ops;
+extern struct clk_ops tegra_twd_ops;
 extern struct clk_ops tegra_cop_ops;
 extern struct clk_ops tegra_bus_ops;
 extern struct clk_ops tegra_blink_clk_ops;

arch/arm/mach-tegra/tegra20_clocks_data.c

@@ -583,6 +583,34 @@ static struct clk_tegra tegra_cclk_hw = {
 DEFINE_CLK_TEGRA(cclk, 0, &tegra_super_ops, 0, mux_cclk,
 		mux_cclk_p, NULL);
 
+static const char *mux_twd[] = {
+	"cclk",
+};
+
+static struct clk *mux_twd_p[] = {
+	&tegra_cclk,
+};
+
+static struct clk tegra_clk_twd;
+static struct clk_tegra tegra_clk_twd_hw = {
+	.hw = {
+		.clk = &tegra_clk_twd,
+	},
+	.max_rate = 1000000000,
+	.mul = 1,
+	.div = 4,
+};
+
+static struct clk tegra_clk_twd = {
+	.name = "twd",
+	.ops = &tegra_twd_ops,
+	.hw = &tegra_clk_twd_hw.hw,
+	.parent = &tegra_cclk,
+	.parent_names = mux_twd,
+	.parents = mux_twd_p,
+	.num_parents = ARRAY_SIZE(mux_twd),
+};
+
 static struct clk tegra_sclk;
 static struct clk_tegra tegra_sclk_hw = {
 	.hw = {
@@ -1027,6 +1055,7 @@ static struct clk_duplicate tegra_clk_duplicates[] = {
 	CLK_DUPLICATE("cop",	"tegra-avp",	"cop"),
 	CLK_DUPLICATE("vde",	"tegra-aes",	"vde"),
 	CLK_DUPLICATE("cclk",	NULL,		"cpu"),
+	CLK_DUPLICATE("twd",	"smp_twd",	NULL),
 };
 
 #define CLK(dev, con, ck)	\
@@ -1057,6 +1086,7 @@ static struct clk *tegra_ptr_clks[] = {
 	&tegra_pll_x,
 	&tegra_pll_e,
 	&tegra_cclk,
+	&tegra_clk_twd,
 	&tegra_sclk,
 	&tegra_hclk,
 	&tegra_pclk,