Re: [PATCH v2 17/18] riscv: dts: starfive: jh7100: Use physical memory ranges for DMA

[Emil Renner Berthing <emil.renner.berthing@canonical.com>]

Samuel Holland wrote:
> 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@sifive.com>
> ---
>
> 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                     | 19 ---------------
>  arch/riscv/Kconfig.socs                       |  2 ++
>  .../boot/dts/starfive/jh7100-common.dtsi      | 24 -------------------
>  arch/riscv/boot/dts/starfive/jh7100.dtsi      |  4 ++++
>  4 files changed, 6 insertions(+), 43 deletions(-)
>
> diff --git a/arch/riscv/Kconfig.errata b/arch/riscv/Kconfig.errata
> index e318119d570de..62700631a5c5d 100644
> --- a/arch/riscv/Kconfig.errata
> +++ b/arch/riscv/Kconfig.errata
> @@ -53,25 +53,6 @@ config ERRATA_SIFIVE_CIP_1200
>
>  	  If you don't know what to do here, say "Y".
>
> -config ERRATA_STARFIVE_JH7100
> -	bool "StarFive JH7100 support"
> -	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
> -	  The StarFive JH7100 was a test chip for the JH7110 and has
> -	  caches that are non-coherent with respect to peripheral DMAs.
> -	  It was designed before the Zicbom extension so needs non-standard
> -	  cache operations through the SiFive cache controller.
> -
> -	  Say "Y" if you want to support the BeagleV Starlight and/or
> -	  StarFive VisionFive V1 boards.
> -
>  config ERRATA_THEAD
>  	bool "T-HEAD errata"
>  	depends on RISCV_ALTERNATIVE
> diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> index 848e7149e4435..a8950206fb750 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

Hi Samuel,

Thanks for working on this! I think you also need to select DMA_DIRECT_REMAP
here, otherwise devices complain that they can't allocate coherent memory at
all.

But even with that added it still doesn't work for me with 6.17 on the JH7100,
the sdcard isn't initialized properly, and I haven't figured out why yet. I
seem to remember your previous version did work though.

Plain 6.17:          https://esmil.dk/pma/upstream.txt
6.17 + this series:  https://esmil.dk/pma/test.txt

The kernel config I'm using is available here:
https://esmil.dk/pma/config.txt

/Emil

>  	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 ae1a6aeb0aeaa..47d0cf55bfc02 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@fa000000 {
> -			reg = <0x0 0xfa000000 0x0 0x1000000>;
> -			no-map;
> -		};
> -
> -		linux,dma@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 7de0732b8eabe..34ff65d65ac7e 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(1)) 0x0>;
>
>  	cpus: cpus {
>  		#address-cells = <1>;
> --
> 2.47.2
>