[PATCH v2 18/18] riscv: dts: eswin: eic7700: Use physical memory ranges for DMA

Samuel Holland samuel.holland at sifive.com
Wed Oct 8 18:57:54 PDT 2025


EIC7700 provides a physical memory region which is a noncached alias of
normal cacheable DRAM. Declare this alias in the devicetree so Linux can
allocate noncached pages for noncoherent DMA, and M-mode firmware can
protect the noncached alias with PMPs.

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

Changes in v2:
 - New patch for v2

 arch/riscv/Kconfig.socs                | 2 ++
 arch/riscv/boot/dts/eswin/eic7700.dtsi | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index a8950206fb750..df3ed1d322fe7 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -9,6 +9,8 @@ config ARCH_ANDES
 
 config ARCH_ESWIN
 	bool "ESWIN SoCs"
+	select RISCV_DMA_NONCOHERENT
+	select RISCV_NONSTANDARD_CACHE_OPS
 	help
 	  This enables support for ESWIN SoC platform hardware,
 	  including the ESWIN EIC7700 SoC.
diff --git a/arch/riscv/boot/dts/eswin/eic7700.dtsi b/arch/riscv/boot/dts/eswin/eic7700.dtsi
index c3ed93008bca1..09292910065b2 100644
--- a/arch/riscv/boot/dts/eswin/eic7700.dtsi
+++ b/arch/riscv/boot/dts/eswin/eic7700.dtsi
@@ -5,9 +5,14 @@
 
 /dts-v1/;
 
+#include <dt-bindings/riscv/physical-memory.h>
+
 / {
 	#address-cells = <2>;
 	#size-cells = <2>;
+	riscv,physical-memory-regions =
+		<0x000 0x80000000 0x00f 0x80000000 (PMA_RWXA | PMA_NONCOHERENT_MEMORY) 0x0>,
+		<0x0c0 0x00000000 0x010 0x00000000 (PMA_RWX | PMA_NONCACHEABLE_MEMORY | PMR_ALIAS(1)) 0x0>;
 
 	cpus {
 		#address-cells = <1>;
-- 
2.47.2




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