[v2] ARM: l2c: Fix prefetch settings dt parsing

Commit Message

Fabrice Gasnier March 10, 2015, 8:59 a.m. UTC

Allow prefetch settings overriding by device tree, in case
l2x0_cache_size_of_parse() returns value, prefetch tuning
properties are silently ignored. E.g. arm,double-linefill* and
arm,prefetch*.
This happens for example, when "cache-size" or "cache-sets"
properties haven't been filled in l2c dt node.

Signed-off-by: Fabrice Gasnier <[e-mail]>
Reviewed-by: Tomasz Figa <[e-mail]>
---
V2: fix typo in commit message
s/prefect/prefetch/ and s/of tree/device tree/
---
 arch/arm/mm/cache-l2x0.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

Comments

Russell King - ARM Linux March 12, 2015, 2:57 p.m. UTC | #1

On Tue, Mar 10, 2015 at 09:59:01AM +0100, Fabrice GASNIER wrote:
> Allow prefetch settings overriding by device tree, in case
> l2x0_cache_size_of_parse() returns value, prefetch tuning
> properties are silently ignored. E.g. arm,double-linefill* and
> arm,prefetch*.
> This happens for example, when "cache-size" or "cache-sets"
> properties haven't been filled in l2c dt node.
> 
> Signed-off-by: Fabrice Gasnier <[e-mail]>
> Reviewed-by: Tomasz Figa <[e-mail]>

Patch is okay, but I think the commit message needs to be better :)

"Allow device tree to override the L2C prefetch settings, even when
l2x0_cache_size_of_parse() fails to parse the cache geometry due to (eg)
missing "cache-size" or "cache-sets" properties."

I think with something along those lines, the patch can be put in my
patch system for when I next get around to applying some kernel patches
instead of reading email. :)

Thanks.

Fabrice Gasnier March 12, 2015, 4:12 p.m. UTC | #2

Hi Russel,

I just sent a V3 to follow your remark.
If this is ok, l'll add it to your patch system.

Thanks for your review.
BR,
Fabrice
On 03/12/2015 03:57 PM, Russell King - ARM Linux wrote:
> On Tue, Mar 10, 2015 at 09:59:01AM +0100, Fabrice GASNIER wrote:
>> Allow prefetch settings overriding by device tree, in case
>> l2x0_cache_size_of_parse() returns value, prefetch tuning
>> properties are silently ignored. E.g. arm,double-linefill* and
>> arm,prefetch*.
>> This happens for example, when "cache-size" or "cache-sets"
>> properties haven't been filled in l2c dt node.
>>
>> Signed-off-by: Fabrice Gasnier <[e-mail]>
>> Reviewed-by: Tomasz Figa <[e-mail]>
> Patch is okay, but I think the commit message needs to be better :)
>
> "Allow device tree to override the L2C prefetch settings, even when
> l2x0_cache_size_of_parse() fails to parse the cache geometry due to (eg)
> missing "cache-size" or "cache-sets" properties."
>
> I think with something along those lines, the patch can be put in my
> patch system for when I next get around to applying some kernel patches
> instead of reading email. :)
>
> Thanks.
>

Patch

diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index c6c7696..8f15f70 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -1131,23 +1131,22 @@  static void __init l2c310_of_parse(const struct device_node *np,
 	}
 
 	ret = l2x0_cache_size_of_parse(np, aux_val, aux_mask, &assoc, SZ_512K);
-	if (ret)
-		return;
-
-	switch (assoc) {
-	case 16:
-		*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		*aux_val |= L310_AUX_CTRL_ASSOCIATIVITY_16;
-		*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		break;
-	case 8:
-		*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		break;
-	default:
-		pr_err("L2C-310 OF cache associativity %d invalid, only 8 or 16 permitted\n",
-		       assoc);
-		break;
+	if (!ret) {
+		switch (assoc) {
+		case 16:
+			*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			*aux_val |= L310_AUX_CTRL_ASSOCIATIVITY_16;
+			*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			break;
+		case 8:
+			*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			break;
+		default:
+			pr_err("L2C-310 OF cache associativity %d invalid, only 8 or 16 permitted\n",
+			       assoc);
+			break;
+		}
 	}
 
 	prefetch = l2x0_saved_regs.prefetch_ctrl;