Issues About MX6_IO_ADDRESS

tony_l_cai — Thu, 25 Jun 2015 07:17:25 GMT

Dear all,

I want to read value of the register CCM_CLPCR(Address: 20C_4000h base + 54h offset = 20C_4054h) ,and I my code is following:

	void __iomem *mx6_CCM_base = MX6_IO_ADDRESS(CCM_BASE_ADDR);
	u32 ret32;
	ret32 = readl(mx6_CCM_base + 0x54);
	printk(KERN_ERR "---mx6_CCM_base + CLKCTL_CLPCR:%x-----reg--:%x--------\n",mx6_CCM_base + 0x54,ret32);

So the log is :---mx6_CCM_base + CLKCTL_CLPCR:f40c4054-----reg--:178--------

But I'm so confused that why the addr is 0xf40c4054 not 0x20c4054(this value is on the reference manual).And I also find the following code

/* define virtual address */

#define PERIPBASE_VIRT 0xF0000000

#define MX6_IO_ADDRESS(x) ((x) - PERIPBASE_VIRT)

Maybe I dont know the basic knowedge about these code,could you give me some guideline in details,especially the virtual address?

and before this ,I want to know the value that I read is right?

3Q~

Re: Issues About MX6_IO_ADDRESS

igorpadykov — Thu, 25 Jun 2015 07:40:33 GMT

HI tony

you are right: 0xf40c4054 is virtual address, that is 0x20c4054 + PERIPBASE_VIRT,

check attached mx6.h (..linux-3.0.35_4.1.0/arch/arm/plat-mxc/include/mach)

#define PERIPBASE_VIRT

0xF2000000

Best regards

igor

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