linux driver, port 2.6.19.2 - 2.6.38-rc2 ARM11 iMX31, amba MBX device LogicPD Litekit GLES driver

Code followed with question

#define MBX_REG_SYS_PHYS_BASE           0xC0000000
#define MBX_REG_RANGE                   0x00004000

static struct resource mxc_reg_resources[] = {
{
        .start = MBX_REG_SYS_PHYS_BASE,
        .end = MBX_REG_SYS_PHYS_BASE + MBX_REG_RANGE - 1,
        .flags = IORESOURCE_MEM }
};

        mbx_reg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!mbx_reg)
                return -EINVAL;

        reg_base = ioremap(mbx_reg->start, resource_size(mbx_reg));
        if (!reg_base) {
                ret = -ENOMEM;
                goto eremap;
        }

        printk(KERN_CRIT "Address: from 0x%08X to 0x%08X\n",
                         mbx_reg->start, reg_base);

        regread = mx3reg_read_reg(mx3reg, MBX1_GLOBREG_REVISION);
        printk(KERN_CRIT "MBX1_GLOBREG_REVISION: 0x%.8X\n", regread);

This code works on iMX31 from LogicPD using 2.6.19.2 with out of tree patching from freescale.

when porting it to 2.6.38-rc2 it no longer works. here are some data results:

Working results:

Address: 0xC7860000 MBX1_GLOBREG_REVISION: 0x01010200

Failed results:开发者_如何学C

Address: 0xC48A0000 MBX1_GLOBREG_REVISION: 0x00000000

Address: 0xC48A8000 MBX1_GLOBREG_REVISION: 0x00000000

Address: 0xC48B8000 MBX1_GLOBREG_REVISION: 0x00000000

Address: 0xC48C0000 MBX1_GLOBREG_REVISION: 0x00000000

maybe interesting is on 2.6.19.2 it always gets the same address mapped yet in 2.6.38-rc2 it does not.

---

Are you sure your defines are still good ? The output for this line should not change :

printk(KERN_CRIT "Address: from 0x%08X to 0x%08X\n",
                         mbx_reg->start, reg_base);

Since it is a physical address. However it is not printed in your output. Check the pripheral you are accessing is clocked.

---

In order to have this device ready to communicate you need to setup the peripheral port remap register

/* Setup Peripheral Port Remap register for AVIC */
       asm("ldr r0, =0xC0000015                                \n\
        mcr p15, 0, r0, c15, c2, 4");

here is the code from the original 2.6.19.2 kernel, executed from a board fixup routine. and of course the clocks would have to be enabled as well, and this driver example is not showing that either.