lkml.org 
[lkml]   [2013]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 8/9] [HACK] ARM: imx: work around v7_cpu_resume link error
On Tue, 19 Feb 2013, Shawn Guo wrote:

> On Mon, Feb 18, 2013 at 12:06:32PM -0500, Nicolas Pitre wrote:
> > Try the following instead. It makes the code simpler and easier to
> > debug.
> >
> It works now. Thanks, Nico. Care to send a patch for it? I'd like
> to apply it.

----- >8

FRom: Nicolas Pitre <nicolas.pitre@linaro.org>
Date: Mon, 18 Feb 2013 12:06:32 -0500 (EST)
Subject: ARM: mach-imx: move early resume code out of the .data section

Building the kernel with allyesconfig fails because the i.mx early
resume code located in the .data section is unable to fixup the bl
relocation as the branch target gets too far away.

The idea of having code in the .data section allows for easy access to
nearby data using relative addressing while the MMU is off. However it
is probably best to move the code back to the .text section where it
belongs and fixup the data access instead. This solves the bl reloc
issue (at least until this becomes a general problem) and simplifies
the code as well.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
---

I'll probably convert other "code in .data" instances as well in the
near future.

diff --git a/arch/arm/mach-imx/headsmp.S b/arch/arm/mach-imx/headsmp.S
index 7e49deb128..27bc06e910 100644
--- a/arch/arm/mach-imx/headsmp.S
+++ b/arch/arm/mach-imx/headsmp.S
@@ -73,16 +73,16 @@ ENDPROC(v7_secondary_startup)

#ifdef CONFIG_PM
/*
- * The following code is located into the .data section. This is to
- * allow phys_l2x0_saved_regs to be accessed with a relative load
- * as we are running on physical address here.
+ * The following code must assume it is running from physical address
+ * where absolute virtual addresses to the data section have to be
+ * turned into relative ones.
*/
- .data
- .align

#ifdef CONFIG_CACHE_L2X0
.macro pl310_resume
- ldr r2, phys_l2x0_saved_regs
+ adr r0, l2x0_saved_regs_offset
+ ldr r2, [r0]
+ add r2, r2, r0
ldr r0, [r2, #L2X0_R_PHY_BASE] @ get physical base of l2x0
ldr r1, [r2, #L2X0_R_AUX_CTRL] @ get aux_ctrl value
str r1, [r0, #L2X0_AUX_CTRL] @ restore aux_ctrl
@@ -90,9 +90,9 @@ ENDPROC(v7_secondary_startup)
str r1, [r0, #L2X0_CTRL] @ re-enable L2
.endm

- .globl phys_l2x0_saved_regs
-phys_l2x0_saved_regs:
- .long 0
+l2x0_saved_regs_offset:
+ .word l2x0_saved_regs - .
+
#else
.macro pl310_resume
.endm
diff --git a/arch/arm/mach-imx/pm-imx6q.c b/arch/arm/mach-imx/pm-imx6q.c
index f7b0c2b1b9..f3791f980d 100644
--- a/arch/arm/mach-imx/pm-imx6q.c
+++ b/arch/arm/mach-imx/pm-imx6q.c
@@ -21,8 +21,6 @@
#include <mach/common.h>
#include <mach/hardware.h>

-extern unsigned long phys_l2x0_saved_regs;
-
static int imx6q_suspend_finish(unsigned long val)
{
cpu_do_idle();
@@ -55,18 +53,5 @@ static const struct platform_suspend_ops imx6q_pm_ops = {

void __init imx6q_pm_init(void)
{
- /*
- * The l2x0 core code provides an infrastucture to save and restore
- * l2x0 registers across suspend/resume cycle. But because imx6q
- * retains L2 content during suspend and needs to resume L2 before
- * MMU is enabled, it can only utilize register saving support and
- * have to take care of restoring on its own. So we save physical
- * address of the data structure used by l2x0 core to save registers,
- * and later restore the necessary ones in imx6q resume entry.
- */
-#ifdef CONFIG_CACHE_L2X0
- phys_l2x0_saved_regs = __pa(&l2x0_saved_regs);
-#endif
-
suspend_set_ops(&imx6q_pm_ops);
}

\
 
 \ /
  Last update: 2013-02-19 05:41    [W:0.076 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site