diff options
| -rw-r--r-- | target/linux/sunxi/patches-4.19/010-v5.3-drivers-ata-ahci_sunxi-Increased-SATA-AHCI-DMA-TX-RX.patch | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/target/linux/sunxi/patches-4.19/010-v5.3-drivers-ata-ahci_sunxi-Increased-SATA-AHCI-DMA-TX-RX.patch b/target/linux/sunxi/patches-4.19/010-v5.3-drivers-ata-ahci_sunxi-Increased-SATA-AHCI-DMA-TX-RX.patch new file mode 100644 index 0000000000..74e51c094c --- /dev/null +++ b/target/linux/sunxi/patches-4.19/010-v5.3-drivers-ata-ahci_sunxi-Increased-SATA-AHCI-DMA-TX-RX.patch @@ -0,0 +1,94 @@ +From 120357ea176e420d313cf8cf2ff35fbe233d3bab Mon Sep 17 00:00:00 2001 +From: Uenal Mutlu <um@mutluit.com> +Date: Mon, 13 May 2019 16:24:10 +0200 +Subject: [PATCH] drivers: ata: ahci_sunxi: Increased SATA/AHCI DMA TX/RX FIFOs + +Increasing the SATA/AHCI DMA TX/RX FIFOs (P0DMACR.TXTS and .RXTS, ie. +TX_TRANSACTION_SIZE and RX_TRANSACTION_SIZE) from default 0x0 each +to 0x3 each, gives a write performance boost of 120 MiB/s to 132 MiB/s +from lame 36 MiB/s to 45 MiB/s previously. +Read performance is above 200 MiB/s. +[tested on SSD using dd bs=4K/8K/12K/16K/20K/24K/32K: peak-perf at 12K] + +Tested on the SBCs Banana Pi R1 (aka Lamobo R1) and Banana Pi M1 which +are based on the Allwinner A20 32bit-SoC (ARMv7-a / arm-linux-gnueabihf). +These devices are RaspberryPi-like small devices. + +This problem of slow SATA write-speed with these small devices lasts +for about 7 years now (beginning with the A10 SoC). Many commentators +throughout the years wrongly assumed the slow write speed was a +hardware limitation. This patch finally solves the problem, which +in fact was just a hard-to-find software problem due to lack of +SATA/AHCI documentation by the SoC-maker Allwinner Technology. + +Lists 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/SATA#Devices_with_SATA_ports + See also http://linux-sunxi.org/Category:Devices_with_SATA_port + +Tested-by: Chen-Yu Tsai <wens@csie.org> +Acked-by: Maxime Ripard <maxime.ripard@bootlin.com> +Reviewed-by: Hans de Goede <hdegoede@redhat.com> +Signed-off-by: Uenal Mutlu <um@mutluit.com> +Signed-off-by: Jens Axboe <axboe@kernel.dk> +--- + drivers/ata/ahci_sunxi.c | 47 ++++++++++++++++++++++++++++++++++++++-- + 1 file changed, 45 insertions(+), 2 deletions(-) + +--- a/drivers/ata/ahci_sunxi.c ++++ b/drivers/ata/ahci_sunxi.c +@@ -157,8 +157,51 @@ static void ahci_sunxi_start_engine(stru + void __iomem *port_mmio = ahci_port_base(ap); + struct ahci_host_priv *hpriv = ap->host->private_data; + +- /* Setup DMA before DMA start */ +- sunxi_clrsetbits(hpriv->mmio + AHCI_P0DMACR, 0x0000ff00, 0x00004400); ++ /* Setup DMA before DMA start ++ * ++ * NOTE: A similar SoC with SATA/AHCI by Texas Instruments documents ++ * this Vendor Specific Port (P0DMACR, aka PxDMACR) in its ++ * User's Guide document (TMS320C674x/OMAP-L1x Processor ++ * Serial ATA (SATA) Controller, Literature Number: SPRUGJ8C, ++ * March 2011, Chapter 4.33 Port DMA Control Register (P0DMACR), ++ * p.68, https://www.ti.com/lit/ug/sprugj8c/sprugj8c.pdf) ++ * as equivalent to the following struct: ++ * ++ * struct AHCI_P0DMACR_t ++ * { ++ * unsigned TXTS : 4; ++ * unsigned RXTS : 4; ++ * unsigned TXABL : 4; ++ * unsigned RXABL : 4; ++ * unsigned Reserved : 16; ++ * }; ++ * ++ * TXTS: Transmit Transaction Size (TX_TRANSACTION_SIZE). ++ * This field defines the DMA transaction size in DWORDs for ++ * transmit (system bus read, device write) operation. [...] ++ * ++ * RXTS: Receive Transaction Size (RX_TRANSACTION_SIZE). ++ * This field defines the Port DMA transaction size in DWORDs ++ * for receive (system bus write, device read) operation. [...] ++ * ++ * TXABL: Transmit Burst Limit. ++ * This field allows software to limit the VBUSP master read ++ * burst size. [...] ++ * ++ * RXABL: Receive Burst Limit. ++ * Allows software to limit the VBUSP master write burst ++ * size. [...] ++ * ++ * Reserved: Reserved. ++ * ++ * ++ * NOTE: According to the above document, the following alternative ++ * to the code below could perhaps be a better option ++ * (or preparation) for possible further improvements later: ++ * sunxi_clrsetbits(hpriv->mmio + AHCI_P0DMACR, 0x0000ffff, ++ * 0x00000033); ++ */ ++ sunxi_clrsetbits(hpriv->mmio + AHCI_P0DMACR, 0x0000ffff, 0x00004433); + + /* Start DMA */ + sunxi_setbits(port_mmio + PORT_CMD, PORT_CMD_START); |