[PATCH v2] ARM: dts: bcm2711: Move emmc2 into its own bus

* [PATCH v2] ARM: dts: bcm2711: Move emmc2 into its own bus
@ 2020-03-04 13:24 Nicolas Saenz Julienne
  2020-03-09 15:20 ` Nicolas Saenz Julienne
  0 siblings, 1 reply; 2+ messages in thread
From: Nicolas Saenz Julienne @ 2020-03-04 13:24 UTC (permalink / raw)
  To: Rob Herring, Nicolas Saenz Julienne
  Cc: devicetree, f.fainelli, phil, linux-kernel,
	bcm-kernel-feedback-list, linux-rpi-kernel, linux-arm-kernel

Depending on bcm2711's revision its emmc2 controller might have
different DMA constraints. Raspberry Pi 4's firmware will take care of
updating those, but only if a certain alias is found in the device tree.
So, move emmc2 into its own bus, so as not to pollute other devices with
dma-ranges changes and create the emmc2bus alias.

Based in Phil ELwell's downstream implementation.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---

Changes since v1:
 - Add comment in dt
 - Fix commit title

 arch/arm/boot/dts/bcm2711-rpi-4-b.dts |  1 +
 arch/arm/boot/dts/bcm2711.dtsi        | 25 ++++++++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
index 1d4b589fe233..e26ea9006378 100644
--- a/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
+++ b/arch/arm/boot/dts/bcm2711-rpi-4-b.dts
@@ -20,6 +20,7 @@ memory@0 {
 	};
 
 	aliases {
+		emmc2bus = &emmc2bus;
 		ethernet0 = &genet;
 		pcie0 = &pcie0;
 	};
diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi
index d1e684d0acfd..a91cf68e3c4c 100644
--- a/arch/arm/boot/dts/bcm2711.dtsi
+++ b/arch/arm/boot/dts/bcm2711.dtsi
@@ -241,17 +241,32 @@ pwm1: pwm@7e20c800 {
 			status = "disabled";
 		};
 
+		hvs@7e400000 {
+			interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
+		};
+	};
+
+	/*
+	 * emmc2 has different DMA constraints based on SoC revisions. It was
+	 * moved into its own bus, so as for RPi4's firmware to update them.
+	 * The firmware will find whether the emmc2bus alias is defined, and if
+	 * so, it'll edit the dma-ranges property below accordingly.
+	 */
+	emmc2bus: emmc2bus {
+		compatible = "simple-bus";
+		#address-cells = <2>;
+		#size-cells = <1>;
+
+		ranges = <0x0 0x7e000000  0x0 0xfe000000  0x01800000>;
+		dma-ranges = <0x0 0xc0000000  0x0 0x00000000  0x40000000>;
+
 		emmc2: emmc2@7e340000 {
 			compatible = "brcm,bcm2711-emmc2";
-			reg = <0x7e340000 0x100>;
+			reg = <0x0 0x7e340000 0x100>;
 			interrupts = <GIC_SPI 126 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&clocks BCM2711_CLOCK_EMMC2>;
 			status = "disabled";
 		};
-
-		hvs@7e400000 {
-			interrupts = <GIC_SPI 97 IRQ_TYPE_LEVEL_HIGH>;
-		};
 	};
 
 	arm-pmu {
-- 
2.25.1


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