[PATCH v3 21/22] riscv: dts: starfive: jh7100: Use physical memory ranges for DMA

[Samuel Holland]

JH7100 provides a physical memory region which is a noncached alias of
normal cacheable DRAM. Now that Linux can apply PMAs by selecting
between aliases of a physical memory region, any page of DRAM can be
marked as noncached for use with DMA, and the preallocated DMA pool is
no longer needed. This allows portable kernels to boot on JH7100 boards.

Signed-off-by: Samuel Holland <samuel.holland at sifive.com>
---

Changes in v3:
 - Fix the entry number of the paired region in the DT
 - Keep the ERRATA_STARFIVE_JH7100 option but update its description

Changes in v2:
 - Move the JH7100 DT changes from jh7100-common.dtsi to jh7100.dtsi
 - Keep RISCV_DMA_NONCOHERENT and RISCV_NONSTANDARD_CACHE_OPS selected

 arch/riscv/Kconfig.errata                     |  9 +++----
 arch/riscv/Kconfig.socs                       |  2 ++
 .../boot/dts/starfive/jh7100-common.dtsi      | 24 -------------------
 arch/riscv/boot/dts/starfive/jh7100.dtsi      |  4 ++++
 4 files changed, 11 insertions(+), 28 deletions(-)

diff --git a/arch/riscv/Kconfig.errata b/arch/riscv/Kconfig.errata
index 46a353a266e5..be5afec66eaa 100644
--- a/arch/riscv/Kconfig.errata
+++ b/arch/riscv/Kconfig.errata
@@ -77,13 +77,11 @@ config ERRATA_SIFIVE_CIP_1200
 	  If you don't know what to do here, say "Y".
 
 config ERRATA_STARFIVE_JH7100
-	bool "StarFive JH7100 support"
+	bool "StarFive JH7100 support for old devicetrees"
 	depends on ARCH_STARFIVE
 	depends on !DMA_DIRECT_REMAP
 	depends on NONPORTABLE
 	select DMA_GLOBAL_POOL
-	select RISCV_DMA_NONCOHERENT
-	select RISCV_NONSTANDARD_CACHE_OPS
 	select SIFIVE_CCACHE
 	default n
 	help
@@ -93,7 +91,10 @@ config ERRATA_STARFIVE_JH7100
 	  cache operations through the SiFive cache controller.
 
 	  Say "Y" if you want to support the BeagleV Starlight and/or
-	  StarFive VisionFive V1 boards.
+	  StarFive VisionFive V1 boards with older devicetrees that reserve
+	  memory for DMA using a "shared-dma-pool". If your devicetree has
+	  the "riscv,physical-memory-regions" property, you should instead
+	  enable RISCV_ISA_XLINUXMEMALIAS and use a portable kernel.
 
 config ERRATA_THEAD
 	bool "T-HEAD errata"
diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index 848e7149e443..a8950206fb75 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -50,6 +50,8 @@ config SOC_STARFIVE
 	bool "StarFive SoCs"
 	select PINCTRL
 	select RESET_CONTROLLER
+	select RISCV_DMA_NONCOHERENT
+	select RISCV_NONSTANDARD_CACHE_OPS
 	select ARM_AMBA
 	help
 	  This enables support for StarFive SoC platform hardware.
diff --git a/arch/riscv/boot/dts/starfive/jh7100-common.dtsi b/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
index ae1a6aeb0aea..47d0cf55bfc0 100644
--- a/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
+++ b/arch/riscv/boot/dts/starfive/jh7100-common.dtsi
@@ -42,30 +42,6 @@ led-ack {
 		};
 	};
 
-	reserved-memory {
-		#address-cells = <2>;
-		#size-cells = <2>;
-		ranges;
-
-		dma-reserved at fa000000 {
-			reg = <0x0 0xfa000000 0x0 0x1000000>;
-			no-map;
-		};
-
-		linux,dma at 107a000000 {
-			compatible = "shared-dma-pool";
-			reg = <0x10 0x7a000000 0x0 0x1000000>;
-			no-map;
-			linux,dma-default;
-		};
-	};
-
-	soc {
-		dma-ranges = <0x00 0x80000000 0x00 0x80000000 0x00 0x7a000000>,
-			     <0x00 0xfa000000 0x10 0x7a000000 0x00 0x01000000>,
-			     <0x00 0xfb000000 0x00 0xfb000000 0x07 0x85000000>;
-	};
-
 	wifi_pwrseq: wifi-pwrseq {
 		compatible = "mmc-pwrseq-simple";
 		reset-gpios = <&gpio 37 GPIO_ACTIVE_LOW>;
diff --git a/arch/riscv/boot/dts/starfive/jh7100.dtsi b/arch/riscv/boot/dts/starfive/jh7100.dtsi
index 7de0732b8eab..c7d7ec9ed8c9 100644
--- a/arch/riscv/boot/dts/starfive/jh7100.dtsi
+++ b/arch/riscv/boot/dts/starfive/jh7100.dtsi
@@ -7,11 +7,15 @@
 /dts-v1/;
 #include <dt-bindings/clock/starfive-jh7100.h>
 #include <dt-bindings/reset/starfive-jh7100.h>
+#include <dt-bindings/riscv/physical-memory.h>
 
 / {
 	compatible = "starfive,jh7100";
 	#address-cells = <2>;
 	#size-cells = <2>;
+	riscv,physical-memory-regions =
+		<0x00 0x80000000 0x08 0x00000000 (PMA_RWXA | PMA_NONCOHERENT_MEMORY) 0x0>,
+		<0x10 0x00000000 0x08 0x00000000 (PMA_RWX | PMA_NONCACHEABLE_MEMORY | PMR_ALIAS(0)) 0x0>;
 
 	cpus: cpus {
 		#address-cells = <1>;
-- 
2.47.2