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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2007 Freescale Semiconductor, Inc. All Rights Reserved.
* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
*/
/*
* i.MX27 specific CPU detection code
*/
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/module.h>
#include "hardware.h"
static int mx27_cpu_rev = -1;
static int mx27_cpu_partnumber;
#define SYS_CHIP_ID 0x00 /* The offset of CHIP ID register */
#define SYSCTRL_OFFSET 0x800 /* Offset from CCM base address */
static int mx27_read_cpu_rev(void)
{
void __iomem *ccm_base;
struct device_node *np;
u32 val;
np = of_find_compatible_node(NULL, NULL, "fsl,imx27-ccm");
ccm_base = of_iomap(np, 0);
of_node_put(np);
BUG_ON(!ccm_base);
/*
* now we have access to the IO registers. As we need
* the silicon revision very early we read it here to
* avoid any further hooks
*/
val = imx_readl(ccm_base + SYSCTRL_OFFSET + SYS_CHIP_ID);
mx27_cpu_partnumber = (int)((val >> 12) & 0xFFFF);
switch (val >> 28) {
case 0:
return IMX_CHIP_REVISION_1_0;
case 1:
return IMX_CHIP_REVISION_2_0;
case 2:
return IMX_CHIP_REVISION_2_1;
default:
return IMX_CHIP_REVISION_UNKNOWN;
}
}
/*
* Returns:
* the silicon revision of the cpu
* -EINVAL - not a mx27
*/
int mx27_revision(void)
{
if (mx27_cpu_rev == -1)
mx27_cpu_rev = mx27_read_cpu_rev();
if (mx27_cpu_partnumber != 0x8821)
return -EINVAL;
return mx27_cpu_rev;
}
EXPORT_SYMBOL(mx27_revision);
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