Re: [PATCH] ARM: l2x0: add prefetch and power ctrl registers configuration support

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On 11/07/13 06:07, Jisheng Zhang wrote:
PL310 supports Prefetch offset/control register from r2p0 and Power
control register from r3p0. This patch adds the support to configure
these two registers if there are. The dt binding document is also updated.

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>
---
  Documentation/devicetree/bindings/arm/l2cc.txt |  4 ++++
  arch/arm/mm/cache-l2x0.c                       | 19 +++++++++++++++++++
  2 files changed, 23 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt b/Documentation/devicetree/bindings/arm/l2cc.txt
index c0c7626..32cd08c 100644
--- a/Documentation/devicetree/bindings/arm/l2cc.txt
+++ b/Documentation/devicetree/bindings/arm/l2cc.txt
@@ -39,6 +39,10 @@ Optional properties:
  - arm,filter-ranges : <start length> Starting address and length of window to
    filter. Addresses in the filter window are directed to the M1 port. Other
    addresses will go to the M0 port.
+- arm,prefetch-ctrl : The value for Prefetch Offset/Control Register if there
+  is. This is a single cell.
+- arm,pwr-ctrl : The value for Power Control Register if there is. This is a
+  single cell.

Jisheng,

I did some research over L2x0/L310 aux-ctrl registers and possible
properties for them. Both properties introduced here, just allow you
to put in a magic number, while IMHO properties should better reflect
the actual function rather than hard-coded values.

A quick look at L310 TRM for Power Control Register gives:

Bit 1: dynamic_clk_gating_en (1=enabled, 0=masked)
Bit 0: standby mode en (1=enabled, 0=masked)

So, properties should one of:

(a) arm,dynamic-clock-gating = <0/1>
    arm,standby-mode = <0/1>
(b) arm,dynamic-clock-gating-enable/-disable;
    arm,standby-mode-enable/-disable

If we want to have set/clear/don't touch behavior, I'd prefer (a) as
it is easier to deal with in code. Moreover, -enable/-disable of (b)
may not always fit the property name, so there will also be
arm,no-feature-foo or arm,force-feature-bar.

The same also applies for Prefetch Control register, too.

Sebastian

  - interrupts : 1 combined interrupt.
  - cache-id-part: cache id part number to be used if it is not present
    on hardware
diff --git a/arch/arm/mm/cache-l2x0.c b/arch/arm/mm/cache-l2x0.c
index 447da6f..8f536ea 100644
--- a/arch/arm/mm/cache-l2x0.c
+++ b/arch/arm/mm/cache-l2x0.c
@@ -704,6 +704,8 @@ static void __init pl310_of_setup(const struct device_node *np,
  	u32 data[3] = { 0, 0, 0 };
  	u32 tag[3] = { 0, 0, 0 };
  	u32 filter[2] = { 0, 0 };
+	u32 l2x0_revision = readl_relaxed(l2x0_base + L2X0_CACHE_ID) &
+		L2X0_CACHE_ID_RTL_MASK;

  	of_property_read_u32_array(np, "arm,tag-latency", tag, ARRAY_SIZE(tag));
  	if (tag[0] && tag[1] && tag[2])
@@ -730,6 +732,23 @@ static void __init pl310_of_setup(const struct device_node *np,
  		writel_relaxed((filter[0] & ~(SZ_1M - 1)) | L2X0_ADDR_FILTER_EN,
  			       l2x0_base + L2X0_ADDR_FILTER_START);
  	}
+
+	if (l2x0_revision >= L2X0_CACHE_ID_RTL_R2P0) {
+		u32 prefetch_ctrl = 0;
+
+		of_property_read_u32(np, "arm,prefetch-ctrl",
+				     &prefetch_ctrl);
+		if (prefetch_ctrl)
+			writel_relaxed(prefetch_ctrl, l2x0_base +
+					L2X0_PREFETCH_CTRL);
+		if (l2x0_revision >= L2X0_CACHE_ID_RTL_R3P0) {
+			u32 pwr_ctrl = 0;
+			of_property_read_u32(np, "arm,pwr-ctrl", &pwr_ctrl);
+			if (pwr_ctrl)
+				writel_relaxed(pwr_ctrl, l2x0_base +
+						L2X0_POWER_CTRL);
+		}
+	}
  }

  static void __init pl310_save(void)


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