diff mbox

[1/2] arm64: dts: r8a7795: Add Cortex-A53 CPU cores

Message ID 1449904607-4060-1-git-send-email-dirk.behme@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dirk Behme Dec. 12, 2015, 7:16 a.m. UTC 
From: Takeshi Kihara <takeshi.kihara.df@renesas.com>

This patch adds Cortex-A53 CPU cores to r8a7795 SoC for a total of 8
cores (4 x Cortex-A57 + 4 x Cortex-A53).

Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
---
Note: This patch is picked from

https://git.kernel.org/cgit/linux/kernel/git/horms/renesas-bsp.git/log/?h=v4.2/rcar-3.0.x

and rebased against

https://git.kernel.org/cgit/linux/kernel/git/horms/renesas.git/log/?h=next renesas-next-20151211v2-v4.4-rc1

 arch/arm64/boot/dts/renesas/r8a7795.dtsi | 46 +++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 7 deletions(-)

Comments

Geert Uytterhoeven Dec. 18, 2015, 11:02 a.m. UTC | #1 
Hi Dirk,

On Sat, Dec 12, 2015 at 8:16 AM, Dirk Behme <dirk.behme@gmail.com> wrote:
> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>
> This patch adds Cortex-A53 CPU cores to r8a7795 SoC for a total of 8
> cores (4 x Cortex-A57 + 4 x Cortex-A53).
>
> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> Signed-off-by: Dirk Behme <dirk.behme@gmail.com>

Thanks, I can confirm this works.

However, as the scheduler is not big.LITTLE aware (running processes are not
migrated automatically to the faster CA57 cores when these are idle), it makes
performance less deterministic.

Hence we would like to postpone this.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Dirk Behme Dec. 18, 2015, 11:58 a.m. UTC | #2 
Hi Geert,

On 18.12.2015 12:02, Geert Uytterhoeven wrote:
> Hi Dirk,
>
> On Sat, Dec 12, 2015 at 8:16 AM, Dirk Behme <dirk.behme@gmail.com> wrote:
>> From: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>>
>> This patch adds Cortex-A53 CPU cores to r8a7795 SoC for a total of 8
>> cores (4 x Cortex-A57 + 4 x Cortex-A53).
>>
>> Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
>> Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
>
> Thanks, I can confirm this works.
>
> However, as the scheduler is not big.LITTLE aware (running processes are not
> migrated automatically to the faster CA57 cores when these are idle), it makes
> performance less deterministic.


What's the plan, then?

Waiting for big.LITTLE getting merged before enabling the A53? Or not 
using the A53 at all?

Best regards

Dirk
diff mbox

Patch

diff --git a/arch/arm64/boot/dts/renesas/r8a7795.dtsi b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
index b9229a4..3633a2a 100644
--- a/arch/arm64/boot/dts/renesas/r8a7795.dtsi
+++ b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
@@ -60,6 +60,30 @@ 
 			device_type = "cpu";
 			enable-method = "psci";
 		};
+		a53_0: cpu@100 {
+			compatible = "arm,cortex-a53", "arm,armv8";
+			reg = <0x100>;
+			device_type = "cpu";
+			enable-method = "psci";
+		};
+		a53_1: cpu@101 {
+			compatible = "arm,cortex-a53","arm,armv8";
+			reg = <0x101>;
+			device_type = "cpu";
+			enable-method = "psci";
+		};
+		a53_2: cpu@102 {
+			compatible = "arm,cortex-a53","arm,armv8";
+			reg = <0x102>;
+			device_type = "cpu";
+			enable-method = "psci";
+		};
+		a53_3: cpu@103 {
+			compatible = "arm,cortex-a53","arm,armv8";
+			reg = <0x103>;
+			device_type = "cpu";
+			enable-method = "psci";
+		};
 	};
 
 	extal_clk: extal {
@@ -115,7 +139,7 @@ 
 			reg = <0x0 0xf1010000 0 0x1000>,
 			      <0x0 0xf1020000 0 0x2000>;
 			interrupts = <GIC_PPI 9
-					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_HIGH)>;
+					(GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_HIGH)>;
 		};
 
 		gpio0: gpio@e6050000 {
@@ -235,23 +259,31 @@ 
 			interrupts = <GIC_SPI 72 IRQ_TYPE_LEVEL_HIGH>,
 				     <GIC_SPI 73 IRQ_TYPE_LEVEL_HIGH>,
 				     <GIC_SPI 74 IRQ_TYPE_LEVEL_HIGH>,
-				     <GIC_SPI 75 IRQ_TYPE_LEVEL_HIGH>;
+				     <GIC_SPI 75 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 84 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 85 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>,
+				     <GIC_SPI 87 IRQ_TYPE_LEVEL_HIGH>;
 			interrupt-affinity = <&a57_0>,
 					     <&a57_1>,
 					     <&a57_2>,
-					     <&a57_3>;
+					     <&a57_3>,
+					     <&a53_0>,
+					     <&a53_1>,
+					     <&a53_2>,
+					     <&a53_3>;
 		};
 
 		timer {
 			compatible = "arm,armv8-timer";
 			interrupts = <GIC_PPI 13
-					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+					(GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
 				     <GIC_PPI 14
-					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+					(GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
 				     <GIC_PPI 11
-					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,
+					(GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>,
 				     <GIC_PPI 10
-					(GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>;
+					(GIC_CPU_MASK_SIMPLE(8) | IRQ_TYPE_LEVEL_LOW)>;
 		};
 
 		cpg: clock-controller@e6150000 {