[PATCH v5] ARM: cache-l2x0.c: save the final aux ctrl value for resuming

[PATCH v5] ARM: cache-l2x0.c: save the final aux ctrl value for resuming

[Yilu Mao]

There is a bug if l2x0 controller has been enabled when calling
l2x0_init, the aux ctrl register will not be saved in l2x0_saved_regs.
Therefore we will use uninitialized l2x0_saved_regs.aux_ctrl for
resuming later.

In this patch, the aux ctrl value is read and saved after it is
initialized. So we have the real value being set for resuming.

Signed-off-by: Yilu Mao <ylmao@marvell.com>
---
 arch/arm/mm/cache-l2x0.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index a53fd2a..670ad48 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -364,14 +364,18 @@ void __init l2x0_init(void __iomem *base, u32 aux_val, u32 aux_mask)
 		/* l2x0 controller is disabled */
 		writel_relaxed(aux, l2x0_base + L2X0_AUX_CTRL);
 
-		l2x0_saved_regs.aux_ctrl = aux;
-
 		l2x0_inv_all();
 
 		/* enable L2X0 */
 		writel_relaxed(1, l2x0_base + L2X0_CTRL);
 	}
 
+	/* Re-read it in case some bits are reserved. */
+	aux = readl_relaxed(l2x0_base + L2X0_AUX_CTRL);
+
+	/* Save the value for resuming. */
+	l2x0_saved_regs.aux_ctrl = aux;
+
 	outer_cache.inv_range = l2x0_inv_range;
 	outer_cache.clean_range = l2x0_clean_range;
 	outer_cache.flush_range = l2x0_flush_range;
-- 
1.7.5.4

Re: [PATCH v5] ARM: cache-l2x0.c: save the final aux ctrl value for resuming

[Catalin Marinas]

On Thu, May 03, 2012 at 01:07:37PM +0100, Yilu Mao wrote:
> There is a bug if l2x0 controller has been enabled when calling
> l2x0_init, the aux ctrl register will not be saved in l2x0_saved_regs.
> Therefore we will use uninitialized l2x0_saved_regs.aux_ctrl for
> resuming later.
> 
> In this patch, the aux ctrl value is read and saved after it is
> initialized. So we have the real value being set for resuming.
> 
> Signed-off-by: Yilu Mao <ylmao@marvell.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Re: [PATCH v5] ARM: cache-l2x0.c: save the final aux ctrl value for resuming

[Yilu Mao]

On 05/03/2012 08:59 PM, Catalin Marinas wrote:
> On Thu, May 03, 2012 at 01:07:37PM +0100, Yilu Mao wrote:
>> There is a bug if l2x0 controller has been enabled when calling
>> l2x0_init, the aux ctrl register will not be saved in l2x0_saved_regs.
>> Therefore we will use uninitialized l2x0_saved_regs.aux_ctrl for
>> resuming later.
>>
>> In this patch, the aux ctrl value is read and saved after it is
>> initialized. So we have the real value being set for resuming.
>>
>> Signed-off-by: Yilu Mao<ylmao@marvell.com>
>
> Acked-by: Catalin Marinas<catalin.marinas@arm.com>
Hi Catalin,

Thanks for reviewing.
I have another question:
There are a lot of registers in l2x0 controller.
Why we only save so small amount of registers?
Base on l2x0 spec, they suggest to save/restore all of them.

-- 
Thanks.

Best Wishes,
Yilu Mao