Adding SKB recycling patches for improving network performance

README.md

@@ -0,0 +1,132 @@
+# Linux kernel for the BeagleV Starlight
+
+## What is this?
+
+The [BeagleV Starlight][bborg] board is a new Linux-capable 64bit RISC-V
+development board. It has not shipped yet, but [beta versions][beta] are out to
+developers. Consequently the board is not yet supported by upstream Linux. This
+tree is meant to collect all the in-development patches for running Linux on
+the board.
+
+[bborg]: https://beagleboard.org/beaglev
+[beta]: https://github.com/beagleboard/beaglev-starlight
+
+## Cross-compiling
+
+Cross-compiling the Linux kernel is surprisingly easy since it doesn't depend
+on any (target) libraries and most distributions already have packages with a
+working cross-compiler. We'll also need a few other tools to build everything:
+```shell
+# Debian/Ubuntu
+sudo apt-get install libncurses-dev libssl-dev bc flex bison make gcc gcc-riscv64-linux-gnu
+# Fedora
+sudo dnf install ncurses-devel openssl openssl-devel bc flex bison make gcc gcc-riscv64-linux-gnu
+# Archlinux
+sudo pacman -S --needed ncurses openssl bc flex bison make gcc riscv64-linux-gnu-gcc
+```
+
+The build system needs to know that we want to cross-compile a kernel for
+RISC-V by setting `ARCH=riscv`. It also needs to know the prefix of our
+cross-compiler using `CROSS_COMPILE=riscv64-linux-gnu-`. Also let's assume
+we're building on an 8-core machine so compilation can be greatly sped up by
+telling make to use all 8 cores with `-j8`.
+
+First we need to configure the kernel though. Linux has a *very* extensive
+configuration system, but you can get a good baseline configuration for the
+board using:
+```shell
+make -j8 ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- starlight_defconfig
+```
+
+There is nothing magic about this configuration other than it has all the
+drivers enabled that are working for the hardware on the board. In fact it has
+very little extra features enabled which is great for compile times, but you
+are very much encouraged to add additional drivers and configure your kernel
+further using
+```shell
+make -j8 ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- nconfig
+```
+
+Now compile the whole thing with
+```
+make -j8 ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu-
+```
+
+
+## Installing
+
+Once the build has finished the resulting kernel can be found at
+```shell
+arch/riscv/boot/Image
+```
+You'll also need the matching device tree at
+```shell
+arch/riscv/boot/dts/starfive/jh7100-starlight.dtb
+```
+These two files should be copied to the boot partition on the SD card. That is
+onto the same file system that contains the `extlinux/extlinux.conf`. On the
+default Fedora image this is mounted at `/boot`.
+
+Now add the following entry to the `extlinux/extlinux.conf` file:
+```
+label My New Kernel
+kernel /Image
+fdt /jh7100-starlight.dtb
+append earlycon root=/dev/mmcblk0p2 rootwait stmmac.chain_mode=1
+```
+
+This assumes your root file system is at `/dev/mmcblk0p2` which it is on the
+default Fedora image. Also if your kernel is very big it might be beneficial to
+use the compressed `Image.gz` rather than the uncompressed `Image`.
+
+The `starlight_defconfig` doesn't enable modules, but if you enabled them in
+your build you'll also need to install them in `/lib/modules/` on the root file
+system. How to do that best is out of scope for this README though.
+
+
+## Status
+
+#### SoC
+
+- [x] GPIO
+- [x] Serial port
+- [x] I2C
+- [x] SPI
+- [x] MMC / SDIO / SD card
+- [x] Random number generator
+- [x] Temperature sensor
+- [x] Ethernet, though a little flaky and `stmmac.chain_mode=1` needed on the cmdline
+- [ ] Clock tree, statically set up by u-boot
+- [ ] Pinctrl/Pinmux, statically set up by u-boot
+- [ ] Watchdog
+- [ ] USB, USB 2.0 seems to work ok, but USB 3.0 is very flaky / broken
+- [ ] Security Engine
+- [ ] Framebuffer
+- [ ] MIPI-DSI
+- [ ] ISP
+- [ ] MIPI-CSI
+- [ ] Video Decode
+- [ ] Video Encode
+- [ ] NVDLA
+- [ ] NNE50
+- [ ] Vision DSP
+
+#### Board
+
+- [x] LED
+- [x] PMIC / Reboot
+- [x] Ethernet PHY
+- [x] AP6236 Wifi
+- [ ] AP6236 Bluetooth
+- [ ] GD25LQ256D SPI flash
+- [ ] HDMI, unknown since framebuffer driver is failing
+
+
+## Contributing
+
+If you're working on cleaning up or upstreaming some of this or adding support
+for more of the SoC I'd very much like to incorporate it into this tree. Either
+send a pull request, mail or contact Esmil on IRC/Slack.
+
+Also I think of this tree mostly as a collection of patches that will hopefully
+mature enough to be submitted upstream. So expect regular rebases.

arch/riscv/Kconfig.socs

@@ -18,6 +18,56 @@ config SOC_SIFIVE
 	help
 	  This enables support for SiFive SoC platform hardware.
 
+config SOC_STARFIVE_VIC7100
+	bool "StarFive VIC7100 SoC"
+	select SOC_SIFIVE
+	select OF_RESERVED_MEM
+	select SIFIVE_L2
+	select SIFIVE_L2_FLUSH
+	select DW_AXI_DMAC_STARFIVE
+	select GPIO_STARFIVE_VIC
+	select HW_RANDOM_STARFIVE_VIC
+	help
+	  This enables support for StarFive VIC7100 SoC Platform Hardware.
+
+menu "StarFive VIC7100 SoC Debug Option"
+	depends on SOC_STARFIVE_VIC7100
+
+config FPGA_GMAC_FLUSH_DDR
+	bool "VIC7100 SOC GMAC description and packet buffer flush"
+	depends on SOC_STARFIVE_VIC7100
+	depends on STMMAC_ETH
+	default y if SOC_STARFIVE_VIC7100
+	help
+	  enable VIC7100 GMAC description and packet buffer flush
+
+config MMC_DW_FLUSH_DDR
+	bool "VIC7100 SOC DW MMC buffer flush"
+	depends on SOC_STARFIVE_VIC7100
+	depends on MMC_DW
+	default y if SOC_STARFIVE_VIC7100
+	help
+	  enable VIC7100 DW MMC description and data buffer flush
+
+config USB_CDNS3_HOST_FLUSH_DMA
+	bool "Cadence USB3 host controller flush dma memery"
+	depends on USB
+	depends on USB_CDNS3
+	depends on SOC_STARFIVE_VIC7100
+	default y if SOC_STARFIVE_VIC7100
+	help
+	  enable VIC7100 DW USB CDNS3 driver data buffer flush
+
+config SOC_STARFIVE_VIC7100_I2C_GPIO
+	bool "VIC7100 SOC I2C GPIO init"
+	depends on I2C_DESIGNWARE_CORE
+	depends on SOC_STARFIVE_VIC7100
+	default y if SOC_STARFIVE_VIC7100
+	help
+	  enable VIC7100 DW I2C GPIO init in Synopsys DesignWare master driver
+
+endmenu
+
 config SOC_VIRT
 	bool "QEMU Virt Machine"
 	select CLINT_TIMER if RISCV_M_MODE

arch/riscv/boot/dts/Makefile

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-subdir-y += sifive
+subdir-y += sifive starfive
 subdir-$(CONFIG_SOC_CANAAN_K210_DTB_BUILTIN) += canaan
 subdir-y += microchip
 

arch/riscv/boot/dts/starfive/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+dtb-$(CONFIG_SOC_STARFIVE_VIC7100) += jh7100-starlight.dtb