Re: [PATCH v2 1/3] PCI: qcom: Refactor common code

Manivannan Sadhasivam
2024-04-02T05:33:41Z

On Wed, Mar 20, 2024 at 12:14:45AM -0700, Shashank Babu Chinta Venkata wrote:
> Refactor common code from RC(Root Complex) and EP(End Point)
> drivers and move them to a common repository. This acts as placeholder

s/repository/driver

> for common source code for both drivers avoiding duplication.

'thus avoiding'

>
> 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-cmn.c | 81 ++++++++++++++++++++++

I'd prefer, pcie-qcom-common.c

> drivers/pci/controller/dwc/pcie-qcom-cmn.h | 14 ++++
> drivers/pci/controller/dwc/pcie-qcom-ep.c | 39 ++---------
> drivers/pci/controller/dwc/pcie-qcom.c | 67 +++---------------
> 6 files changed, 113 insertions(+), 94 deletions(-)
> create mode 100644 drivers/pci/controller/dwc/pcie-qcom-cmn.c
> create mode 100644 drivers/pci/controller/dwc/pcie-qcom-cmn.h
>
> diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
> index 8afacc90c63b..41d2746edc5f 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_CMN

I'd prefer, '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_CMN
> 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_CMN
> 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..521572093ebf 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-$(CONFIG_PCIE_QCOM_CMN) += pcie-qcom-cmn.o
> obj-$(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-cmn.c b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
> new file mode 100644
> index 000000000000..64fa412ec293
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.c
> @@ -0,0 +1,81 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2014-2015, 2020 The Linux Foundation. All rights reserved.
> + * Copyright 2015, 2021 Linaro Limited.

Copyright (c)

> + * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
> + *
> + */
> +
> +#include <linux/debugfs.h>

Why do you need this header in this patch?

> +#include <linux/pci.h>
> +#include <linux/interconnect.h>
> +
> +#include "../../pci.h"
> +#include "pcie-designware.h"
> +#include "pcie-qcom-cmn.h"
> +
> +#define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \
> + Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_link_speed[speed]))
> +
> +int qcom_pcie_cmn_icc_get_resource(struct dw_pcie *pci, struct icc_path *icc_mem)

qcom_pcie_common_icc_get?

> +{
> + if (IS_ERR(pci))
> + return PTR_ERR(pci);

Why this check is needed?

> +
> + icc_mem = devm_of_icc_get(pci->dev, "pcie-mem");
> + if (IS_ERR(icc_mem))
> + return PTR_ERR(icc_mem);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(qcom_pcie_cmn_icc_get_resource);
> +
> +int qcom_pcie_cmn_icc_init(struct dw_pcie *pci, struct icc_path *icc_mem)

qcom_pcie_common_icc_init?

> +{
> + int ret;
> +
> + if (IS_ERR(pci))
> + return PTR_ERR(pci);
> +

Again, why this is needed?

> + if (IS_ERR(icc_mem))
> + return PTR_ERR(icc_mem);
> +

If 'devm_of_icc_get' has failed previously we wouldn't reach here. And also,
there is no need to check for NULL since the ICC core already does that.

> + /*
> + * 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_cmn_icc_init);
> +
> +void qcom_pcie_cmn_icc_update(struct dw_pcie *pci, struct icc_path *icc_mem)

qcom_pcie_common_icc_update?

> +{
> + 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);
> +

You can keep the link check here since that should work for both RC and EP.

> + 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",
> + ret);
> +}
> +EXPORT_SYMBOL_GPL(qcom_pcie_cmn_icc_update);
> diff --git a/drivers/pci/controller/dwc/pcie-qcom-cmn.h b/drivers/pci/controller/dwc/pcie-qcom-cmn.h
> new file mode 100644
> index 000000000000..845eda23ae59
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pcie-qcom-cmn.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2014-2015, 2020 The Linux Foundation. All rights reserved.
> + * Copyright 2015, 2021 Linaro Limited.
> + * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/pci.h>
> +#include "../../pci.h"
> +#include "pcie-designware.h"

Again, headers should be included only if it is used in the same file itself.

- Mani

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