imx: timer: Modify GPT timer driver for mx7

Modify the GPT common platform driver for mx7 which only use 24Mhz
OSC as clock source.

Note: at default, the mx7d will use system counter as timer. The GPT
is disabled.

Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
diff --git a/arch/arm/mach-imx/timer.c b/arch/arm/mach-imx/timer.c
index fa1941a..a3c4788 100644
--- a/arch/arm/mach-imx/timer.c
+++ b/arch/arm/mach-imx/timer.c
@@ -39,18 +39,16 @@
 #define GPTPR_PRESCALER24M_SHIFT 12
 #define GPTPR_PRESCALER24M_MASK (0xF << GPTPR_PRESCALER24M_SHIFT)
 
+DECLARE_GLOBAL_DATA_PTR;
+
 static inline int gpt_has_clk_source_osc(void)
 {
-#if defined(CONFIG_MX6)
 	if (((is_mx6dq()) && (soc_rev() > CHIP_REV_1_0)) ||
 	    is_mx6dqp() || is_mx6sdl() || is_mx6sx() || is_mx6ul() ||
-	    is_mx6ull() || is_mx6sll())
+	    is_mx6ull() || is_mx6sll() || is_mx7())
 		return 1;
 
 	return 0;
-#else
-	return 0;
-#endif
 }
 
 static inline ulong gpt_get_clk(void)
@@ -73,7 +71,8 @@
 	__raw_writel(GPTCR_SWR, &cur_gpt->control);
 
 	/* We have no udelay by now */
-	__raw_writel(0, &cur_gpt->control);
+	for (i = 0; i < 100; i++)
+		__raw_writel(0, &cur_gpt->control);
 
 	i = __raw_readl(&cur_gpt->control);
 	i &= ~GPTCR_CLKSOURCE_MASK;
@@ -87,7 +86,7 @@
 		 * Enable bit and prescaler
 		 */
 		if (is_mx6sdl() || is_mx6sx() || is_mx6ul() || is_mx6ull() ||
-		    is_mx6sll()) {
+		    is_mx6sll() || is_mx7()) {
 			i |= GPTCR_24MEN;
 
 			/* Produce 3Mhz clock */
@@ -103,6 +102,9 @@
 #endif
 	__raw_writel(i, &cur_gpt->control);
 
+	gd->arch.tbl = __raw_readl(&cur_gpt->counter);
+	gd->arch.tbu = 0;
+
 	return 0;
 }