On Mon, Jan 25, 2021 at 02:40:10PM +0800, xxm wrote: > Hi Leon, > > Thanks for your reply. > > 在 2021/1/25 13:48, Leon Romanovsky 写道: > > On Mon, Jan 25, 2021 at 10:49:27AM +0800, Simon Xue wrote: > > > pcie-dw-rockchip is based on DWC IP. But pcie-rockchip-host > > > is Rockchip designed IP which is only used for RK3399. So all the following > > > non-RK3399 SoCs should use this driver. > > > > > > Signed-off-by: Simon Xue <xxm@xxxxxxxxxxxxxx> > > > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> > > > --- > > > drivers/pci/controller/dwc/Kconfig | 9 + > > > drivers/pci/controller/dwc/Makefile | 1 + > > > drivers/pci/controller/dwc/pcie-dw-rockchip.c | 286 ++++++++++++++++++ > > > 3 files changed, 296 insertions(+) > > > create mode 100644 drivers/pci/controller/dwc/pcie-dw-rockchip.c > > > > > > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig > > > index 22c5529e9a65..aee408fe9283 100644 > > > --- a/drivers/pci/controller/dwc/Kconfig > > > +++ b/drivers/pci/controller/dwc/Kconfig > > > @@ -214,6 +214,15 @@ config PCIE_ARTPEC6_EP > > > Enables support for the PCIe controller in the ARTPEC-6 SoC to work in > > > endpoint mode. This uses the DesignWare core. > > > > > > +config PCIE_ROCKCHIP_DW_HOST > > > + bool "Rockchip DesignWare PCIe controller" > > > + select PCIE_DW > > > + select PCIE_DW_HOST > > > + depends on ARCH_ROCKCHIP || COMPILE_TEST > > > + depends on OF > > > + help > > > + Enables support for the DW PCIe controller in the Rockchip SoC. > > > + > > > config PCIE_INTEL_GW > > > bool "Intel Gateway PCIe host controller support" > > > depends on OF && (X86 || COMPILE_TEST) > > > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile > > > index a751553fa0db..30eef8e9ee8a 100644 > > > --- a/drivers/pci/controller/dwc/Makefile > > > +++ b/drivers/pci/controller/dwc/Makefile > > > @@ -13,6 +13,7 @@ obj-$(CONFIG_PCI_LAYERSCAPE_EP) += pci-layerscape-ep.o > > > obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o > > > obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o > > > obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o > > > +obj-$(CONFIG_PCIE_ROCKCHIP_DW_HOST) += pcie-dw-rockchip.o > > > obj-$(CONFIG_PCIE_INTEL_GW) += pcie-intel-gw.o > > > obj-$(CONFIG_PCIE_KIRIN) += pcie-kirin.o > > > obj-$(CONFIG_PCIE_HISI_STB) += pcie-histb.o > > > diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c > > > new file mode 100644 > > > index 000000000000..07f6d1cd5853 > > > --- /dev/null > > > +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c > > > @@ -0,0 +1,286 @@ > > > +// SPDX-License-Identifier: GPL-2.0 > > > +/* > > > + * PCIe host controller driver for Rockchip SoCs > > > + * > > > + * Copyright (C) 2021 Rockchip Electronics Co., Ltd. > > > + * http://www.rock-chips.com > > > + * > > > + * Author: Simon Xue <xxm@xxxxxxxxxxxxxx> > > > + */ > > > + > > > +#include <linux/clk.h> > > > +#include <linux/gpio/consumer.h> > > > +#include <linux/mfd/syscon.h> > > > +#include <linux/module.h> > > > +#include <linux/of_device.h> > > > +#include <linux/phy/phy.h> > > > +#include <linux/platform_device.h> > > > +#include <linux/regmap.h> > > > +#include <linux/reset.h> > > > + > > > +#include "pcie-designware.h" > > > + > > > +/* > > > + * The upper 16 bits of PCIE_CLIENT_CONFIG are a write > > > + * mask for the lower 16 bits. This allows atomic updates > > > + * of the register without locking. > > > + */ > > This is correct only for the variables that naturally aligned, I imagine > > that this is the case here and in the Linux, but better do not write comments > > in the code that are not accurate. > > Ok, will remove. > I wonder what it would be when outside the Linux? Could you share some information? The C standard says nothing about atomicity, integer assignment maybe atomic, maybe it isn’t. There is no guarantee, plain integer assignment in C is non-atomic by definition. The atomicity of u32 is very dependent on hardware vendor, memory model and compiler, for example x86 and ARMs guarantee atomicity for u32. This is why I said that probably here (Linux) it is ok and you are not alone in expecting lockless write. Thanks > > > Thanks > > > > > > > >
