Commit ddc32a87 authored by Juha Yrjola's avatar Juha Yrjola Committed by Tony Lindgren
Browse files

ARM: OMAP2: Make sure peripherals can be accessed after clk_enable 



Some peripherals seem to need additional delay until they
can actually be accessed after enabling their FCLK and ICLK.

Signed-off-by: default avatarJuha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent dc0d794e

arch/arm/mach-omap2/clock.c

+47 −1
Original line number Diff line number Diff line
@@ -32,6 +32,8 @@ 
#include "memory.h"

#include "clock.h"



#undef DEBUG



//#define DOWN_VARIABLE_DPLL 1			/* Experimental */



static struct prcm_config *curr_prcm_set;
@@ -114,10 +116,52 @@ static void omap2_clk_fixed_enable(struct clk *clk) 
	while (!(CM_IDLEST_CKGEN & cval)) {		/* Wait for lock */

		++i;

		udelay(1);

		if (i == 100000)

		if (i == 100000) {

			printk(KERN_ERR "Clock %s didn't lock\n", clk->name);

			break;

		}

	}

}



static void omap2_clk_wait_ready(struct clk *clk)

{

	unsigned long reg, other_reg, st_reg;

	u32 bit;

	int i;



	reg = (unsigned long) clk->enable_reg;

	if (reg == (unsigned long) &CM_FCLKEN1_CORE ||

	    reg == (unsigned long) &CM_FCLKEN2_CORE)

		other_reg = (reg & ~0xf0) | 0x10;

	else if (reg == (unsigned long) &CM_ICLKEN1_CORE ||

		 reg == (unsigned long) &CM_ICLKEN2_CORE)

		other_reg = (reg & ~0xf0) | 0x00;

	else

		return;



	/* No check for DSS or cam clocks */

	if ((reg & 0x0f) == 0) {

		if (clk->enable_bit <= 1 || clk->enable_bit == 31)

			return;

	}



	/* Check if both functional and interface clocks

	 * are running. */

	bit = 1 << clk->enable_bit;

	if (!(__raw_readl(other_reg) & bit))

		return;

	st_reg = (other_reg & ~0xf0) | 0x20;

	i = 0;

	while (!(__raw_readl(st_reg) & bit)) {

		i++;

		if (i == 100000) {

			printk(KERN_ERR "Timeout enabling clock %s\n", clk->name);

			break;

		}

	}

	if (i)

		pr_debug("Clock %s stable after %d loops\n", clk->name, i);

}



/* Enables clock without considering parent dependencies or use count

 * REVISIT: Maybe change this to use clk->enable like on omap1?
@@ -150,6 +194,8 @@ static int _omap2_clk_enable(struct clk * clk) 
	__raw_writel(regval32, clk->enable_reg);

	wmb();



	omap2_clk_wait_ready(clk);



	return 0;

}