Re: [RFC PATCH] drivers: ata: ahci_sunxi: Increased SATA/AHCI DMA TX/RX FIFOs

From: Maxime Ripard <maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>
To: Uenal Mutlu <um-lNbj7F0cCK5BDgjK7y7TUQ@public.gmane.org>
Cc: Jens Axboe <axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org>,
	Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
	linux-ide-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org,
	u-boot-0aAXYlwwYIKGBzrmiIFOJg@public.gmane.org,
	linux-amarula-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org,
	Jagan Teki
	<jagan-dyjBcgdgk7Pe9wHmmfpqLFaTQe2KTcn/@public.gmane.org>,
	Pablo Greco
	<pgreco-/kQrlZ55X3WoClj4AeEUq9i2O/JbrIOy@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Oliver Schinagl <oliver-dxLnbx3+1qmEVqv0pETR8A@public.gmane.org>,
	Linus Walleij
	<linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	FUKAUMI Naoki <naobsd-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org>
Subject: Re: [RFC PATCH] drivers: ata: ahci_sunxi: Increased SATA/AHCI DMA TX/RX FIFOs
Date: Sun, 12 May 2019 14:12:45 +0200	[thread overview]
Message-ID: <20190512121245.l3cvg4std6yanwix@flea> (raw)
In-Reply-To: <20190510192550.17458-1-um-lNbj7F0cCK5BDgjK7y7TUQ@public.gmane.org>

Hi,

On Fri, May 10, 2019 at 09:25:50PM +0200, Uenal Mutlu wrote:
> Increasing the SATA/AHCI DMA TX/RX FIFOs (P0DMACR.TXTS and .RXTS) from
> default 0x0 each to 0x3 each gives a write performance boost of 120MB/s
> from lame 36MB/s to 45MB/s previously. Read performance is about 200MB/s
> [tested on SSD using dd bs=4K count=512K].
>
> Tested on the Banana Pi R1 (aka Lamobo R1) and Banana Pi M1 SBCs
> with Allwinner A20 32bit-SoCs (ARMv7-a / arm-linux-gnueabihf).
> These devices are RaspberryPi-like small devices.
>
> RFC: Since more than about 25 similar SBC/SoC models do use the
> ahci_sunxi driver, users are encouraged to test it on all the
> affected boards and give feedback.
>
> List of the affected sunxi and other boards and SoCs with SATA using
> the ahci_sunxi driver:
>   $ grep -i -e "^&ahci" arch/arm/boot/dts/sun*dts
>   and http://linux-sunxi.org/Category:Devices_with_SATA_port
>
> Signed-off-by: Uenal Mutlu <um-lNbj7F0cCK5BDgjK7y7TUQ@public.gmane.org>
> ---
>  drivers/ata/ahci_sunxi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/ata/ahci_sunxi.c b/drivers/ata/ahci_sunxi.c
> index 911710643305..257986431c79 100644
> --- a/drivers/ata/ahci_sunxi.c
> +++ b/drivers/ata/ahci_sunxi.c
> @@ -158,7 +158,7 @@ static void ahci_sunxi_start_engine(struct ata_port *ap)
>  	struct ahci_host_priv *hpriv = ap->host->private_data;
>
>  	/* Setup DMA before DMA start */
> -	sunxi_clrsetbits(hpriv->mmio + AHCI_P0DMACR, 0x0000ff00, 0x00004400);
> +	sunxi_clrsetbits(hpriv->mmio + AHCI_P0DMACR, 0x0000ffff, 0x00004433);

Having comments / defines here would be great, once fixed:
Acked-by: Maxime Ripard <maxime.ripard-LDxbnhwyfcJBDgjK7y7TUQ@public.gmane.org>

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com