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Commit 56b7eec0 authored by Lothar Waßmann's avatar Lothar Waßmann Committed by Shawn Guo
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ARM: mxs: Fix BUG() when invoking mxs_restart() from interrupt context 



The mxs_restart() function uses of_iomap() which triggers the
following BUG_ON(in_interrupt()) when called in interrupt context
(e.g. thru SYSRQ-B):

      SysRq : Resetting
      ------------[ cut here ]------------
      kernel BUG at mm/vmalloc.c:1310!
      Internal error: Oops - BUG: 0 [#1] PREEMPT ARM
      Modules linked in: i2c_dev
      CPU: 0 PID: 0 Comm: swapper Not tainted 3.11.0-rc2-next-20130729-karo+ #196
      task: c04e1c38 ti: c04d8000 task.ti: c04d8000
      PC is at __get_vm_area_node.clone.25+0x34/0x140
      LR is at get_vm_area_caller+0x38/0x44
      pc : [<c008a988>]    lr : [<c008b434>]    psr: 20000013
      sp : c04d9db0  ip : 00000001  fp : 00000001
      r10: c8800000  r9 : 00000000  r8 : 000000d0
      r7 : 00002000  r6 : 00000001  r5 : 00000001  r4 : 00002000
      r3 : 00010000  r2 : 00000001  r1 : c04d9db0  r0 : 00002000
      Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
      Control: 0005317f  Table: 46920000  DAC: 00000017
      Process swapper (pid: 0, stack limit = 0xc04d81b8)

Create the mapping upon startup from mxs_machine_init().

Signed-off-by: default avatarLothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: default avatarShawn Guo <shawn.guo@linaro.org>
parent 5cd86ef5

arch/arm/mach-mxs/mach-mxs.c

+32 −21
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ 
static u32 chipid;

static u32 socid;



static void __iomem *reset_addr;



static inline void __mxs_setl(u32 mask, void __iomem *reg)

{

	__raw_writel(mask, reg + MXS_SET_ADDR);
@@ -400,6 +402,27 @@ static const char __init *mxs_get_revision(void) 
		return kasprintf(GFP_KERNEL, "%s", "Unknown");

}



#define MX23_CLKCTRL_RESET_OFFSET	0x120

#define MX28_CLKCTRL_RESET_OFFSET	0x1e0



static int __init mxs_restart_init(void)

{

	struct device_node *np;



	np = of_find_compatible_node(NULL, NULL, "fsl,clkctrl");

	reset_addr = of_iomap(np, 0);

	if (!reset_addr)

		return -ENODEV;



	if (of_device_is_compatible(np, "fsl,imx23-clkctrl"))

		reset_addr += MX23_CLKCTRL_RESET_OFFSET;

	else

		reset_addr += MX28_CLKCTRL_RESET_OFFSET;

	of_node_put(np);



	return 0;

}



static void __init mxs_machine_init(void)

{

	struct device_node *root;
@@ -443,12 +466,12 @@ static void __init mxs_machine_init(void) 
	of_platform_populate(NULL, of_default_bus_match_table,

			     NULL, parent);



	mxs_restart_init();



	if (of_machine_is_compatible("karo,tx28"))

		tx28_post_init();

}



#define MX23_CLKCTRL_RESET_OFFSET	0x120

#define MX28_CLKCTRL_RESET_OFFSET	0x1e0

#define MXS_CLKCTRL_RESET_CHIP		(1 << 1)



/*
@@ -456,19 +479,7 @@ static void __init mxs_machine_init(void) 
 */

static void mxs_restart(enum reboot_mode mode, const char *cmd)

{

	struct device_node *np;

	void __iomem *reset_addr;



	np = of_find_compatible_node(NULL, NULL, "fsl,clkctrl");

	reset_addr = of_iomap(np, 0);

	if (!reset_addr)

		goto soft;



	if (of_device_is_compatible(np, "fsl,imx23-clkctrl"))

		reset_addr += MX23_CLKCTRL_RESET_OFFSET;

	else

		reset_addr += MX28_CLKCTRL_RESET_OFFSET;



	if (reset_addr) {

		/* reset the chip */

		__mxs_setl(MXS_CLKCTRL_RESET_CHIP, reset_addr);
@@ -476,8 +487,8 @@ static void mxs_restart(enum reboot_mode mode, const char *cmd) 


		/* Delay to allow the serial port to show the message */

		mdelay(50);

	}



soft:

	/* We'll take a jump through zero as a poor second */

	soft_restart(0);

}