Re: [PATCH v3 1/3] PCI: qcom: Refactor common code

[Manivannan Sadhasivam <mani@kernel.org>]

On Thu, Apr 18, 2024 at 05:09:34PM -0700, Shashank Babu Chinta Venkata wrote:
> Refactor common code from RC(Root Complex) and EP(End Point)
> drivers and move them to a common driver. This acts as placeholder
> for common source code for both drivers, thus avoiding duplication.
> 
> Signed-off-by: Shashank Babu Chinta Venkata <quic_schintav@quicinc.com>
> ---
>  drivers/pci/controller/dwc/Kconfig            |  5 ++
>  drivers/pci/controller/dwc/Makefile           |  1 +
>  drivers/pci/controller/dwc/pcie-qcom-common.c | 75 +++++++++++++++++++
>  drivers/pci/controller/dwc/pcie-qcom-common.h | 12 +++
>  drivers/pci/controller/dwc/pcie-qcom-ep.c     | 39 +---------
>  drivers/pci/controller/dwc/pcie-qcom.c        | 67 ++---------------
>  6 files changed, 105 insertions(+), 94 deletions(-)
>  create mode 100644 drivers/pci/controller/dwc/pcie-qcom-common.c
>  create mode 100644 drivers/pci/controller/dwc/pcie-qcom-common.h
> 
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 8afacc90c63b..1599550cd628 100644
> --- a/drivers/pci/controller/dwc/Kconfig
> +++ b/drivers/pci/controller/dwc/Kconfig
> @@ -265,12 +265,16 @@ config PCIE_DW_PLAT_EP
>  	  order to enable device-specific features PCI_DW_PLAT_EP must be
>  	  selected.
>  
> +config PCIE_QCOM_COMMON
> +	bool
> +
>  config PCIE_QCOM
>  	bool "Qualcomm PCIe controller (host mode)"
>  	depends on OF && (ARCH_QCOM || COMPILE_TEST)
>  	depends on PCI_MSI
>  	select PCIE_DW_HOST
>  	select CRC8
> +	select PCIE_QCOM_COMMON
>  	help
>  	  Say Y here to enable PCIe controller support on Qualcomm SoCs. The
>  	  PCIe controller uses the DesignWare core plus Qualcomm-specific
> @@ -281,6 +285,7 @@ config PCIE_QCOM_EP
>  	depends on OF && (ARCH_QCOM || COMPILE_TEST)
>  	depends on PCI_ENDPOINT
>  	select PCIE_DW_EP
> +	select PCIE_QCOM_COMMON
>  	help
>  	  Say Y here to enable support for the PCIe controllers on Qualcomm SoCs
>  	  to work in endpoint mode. The PCIe controller uses the DesignWare core
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index bac103faa523..3f557dd60c38 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
>  obj-$(CONFIG_PCI_LAYERSCAPE_EP) += pci-layerscape-ep.o
>  obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
>  obj-$(CONFIG_PCIE_QCOM_EP) += pcie-qcom-ep.o
> +obj-$(CONFIG_PCIE_QCOM_COMMON) += pcie-qcom-common.o
>  obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
>  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
>  obj-$(CONFIG_PCIE_ROCKCHIP_DW_HOST) += pcie-dw-rockchip.o
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-common.c b/drivers/pci/controller/dwc/pcie-qcom-common.c
> new file mode 100644
> index 000000000000..dc2120ec5fef
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-qcom-common.c
> @@ -0,0 +1,75 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2014-2015, 2020 The Linux Foundation. All rights reserved.
> + * Copyright (c) 2015, 2021 Linaro Limited.
> + * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
> + *
> + */
> +
> +#include <linux/pci.h>
> +#include <linux/interconnect.h>

Sort these alphabetically.

> +
> +#include "../../pci.h"
> +#include "pcie-designware.h"
> +#include "pcie-qcom-common.h"
> +
> +#define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
> +		Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
> +
> +int qcom_pcie_common_icc_get_resource(struct dw_pcie *pci, struct icc_path **icc_mem_p)

This API can be used for other paths also in the future (like CPU-PCIe). So it
should accept the path name and directly return the 'struct icc_path' pointer.

> +{
> +	*icc_mem_p = devm_of_icc_get(pci->dev, "pcie-mem");
> +	if (IS_ERR_OR_NULL(icc_mem_p))
> +		return PTR_ERR(icc_mem_p);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_pcie_common_icc_get_resource);
> +
> +int qcom_pcie_common_icc_init(struct dw_pcie *pci, struct icc_path *icc_mem)
> +{
> +	int ret;
> +
> +	/*
> +	 * Some Qualcomm platforms require interconnect bandwidth constraints
> +	 * to be set before enabling interconnect clocks.
> +	 *
> +	 * Set an initial peak bandwidth corresponding to single-lane Gen 1
> +	 * for the pcie-mem path.
> +	 */
> +	ret = icc_set_bw(icc_mem, 0, QCOM_PCIE_LINK_SPEED_TO_BW(1));
> +	if (ret) {
> +		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_pcie_common_icc_init);
> +
> +void qcom_pcie_common_icc_update(struct dw_pcie *pci, struct icc_path *icc_mem)
> +{
> +	u32 offset, status;
> +	int speed, width;
> +	int ret;
> +
> +	if (!icc_mem)
> +		return;
> +
> +	offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
> +	status = readw(pci->dbi_base + offset + PCI_EXP_LNKSTA);
> +
> +	/* Only update constraints if link is up. */
> +	if (!(status & PCI_EXP_LNKSTA_DLLLA))
> +		return;
> +
> +	speed = FIELD_GET(PCI_EXP_LNKSTA_CLS, status);
> +	width = FIELD_GET(PCI_EXP_LNKSTA_NLW, status);
> +
> +	ret = icc_set_bw(icc_mem, 0, width * QCOM_PCIE_LINK_SPEED_TO_BW(speed));
> +	if (ret)
> +		dev_err(pci->dev, "failed to set interconnect bandwidth: %d\n",

'Failed to set bandwidth for PCIe-MEM interconnect path: %d\n'

- Mani

-- 
மணிவண்ணன் சதாசிவம்