linux-kernel - Re: [PATCH 2/5] drivers: mtd: nand: Add qpic

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Message-ID: <CAA8EJpquDwDg+OrZKeJrTWEtokCF7uyHMyzCFK2etSsDip8_6Q@mail.gmail.com>
Date: Thu, 15 Feb 2024 17:00:00 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Md Sadre Alam <quic_mdalam@...cinc.com>
Cc: andersson@...nel.org, konrad.dybcio@...aro.org, broonie@...nel.org, 
	robh@...nel.org, krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org, 
	miquel.raynal@...tlin.com, richard@....at, vigneshr@...com, 
	manivannan.sadhasivam@...aro.org, linux-arm-msm@...r.kernel.org, 
	linux-spi@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-mtd@...ts.infradead.org, 
	quic_srichara@...cinc.com, quic_varada@...cinc.com
Subject: Re: [PATCH 2/5] drivers: mtd: nand: Add qpic_common API file

On Thu, 15 Feb 2024 at 15:53, Md Sadre Alam <quic_mdalam@...cinc.com> wrote:
>
> Add qpic_common.c file which hold all the common
> qpic APIs which will be used by both qpic raw nand
> driver and qpic spi nand driver.
>
> Co-developed-by: Sricharan Ramabadhran <quic_srichara@...cinc.com>
> Signed-off-by: Sricharan Ramabadhran <quic_srichara@...cinc.com>
> Co-developed-by: Varadarajan Narayanan <quic_varada@...cinc.com>
> Signed-off-by: Varadarajan Narayanan <quic_varada@...cinc.com>
> Signed-off-by: Md Sadre Alam <quic_mdalam@...cinc.com>
> ---
>  drivers/mtd/nand/Makefile            |    1 +
>  drivers/mtd/nand/qpic_common.c       |  786 +++++++++++++++++
>  drivers/mtd/nand/raw/qcom_nandc.c    | 1226 +-------------------------
>  include/linux/mtd/nand-qpic-common.h |  488 ++++++++++
>  4 files changed, 1291 insertions(+), 1210 deletions(-)
>  create mode 100644 drivers/mtd/nand/qpic_common.c
>  create mode 100644 include/linux/mtd/nand-qpic-common.h
>
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index 19e1291ac4d5..131707a41293 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -12,3 +12,4 @@ nandcore-$(CONFIG_MTD_NAND_ECC) += ecc.o
>  nandcore-$(CONFIG_MTD_NAND_ECC_SW_HAMMING) += ecc-sw-hamming.o
>  nandcore-$(CONFIG_MTD_NAND_ECC_SW_BCH) += ecc-sw-bch.o
>  nandcore-$(CONFIG_MTD_NAND_ECC_MXIC) += ecc-mxic.o
> +obj-y += qpic_common.o
> diff --git a/drivers/mtd/nand/qpic_common.c b/drivers/mtd/nand/qpic_common.c
> new file mode 100644
> index 000000000000..4d74ba888028
> --- /dev/null
> +++ b/drivers/mtd/nand/qpic_common.c
> @@ -0,0 +1,786 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * QPIC Controller common API file.
> + * Copyright (C) 2023  Qualcomm Inc.
> + * Authors:    Md sadre Alam           <quic_mdalam@...cinc.com>
> + *             Sricharan R             <quic_srichara@...cinc.com>
> + *             Varadarajan Narayanan   <quic_varada@...cinc.com>

This is a bit of an exaggeration. You are moving code, not writing new
code. Please retain the existing copyrights for the moved code.

> + *
> + */
> +
> +#include <linux/mtd/nand-qpic-common.h>
> +
> +struct qcom_nand_controller *
> +get_qcom_nand_controller(struct nand_chip *chip)
> +{
> +       return container_of(chip->controller, struct qcom_nand_controller,
> +                           controller);
> +}
> +EXPORT_SYMBOL(get_qcom_nand_controller);

NAK for adding functions to the global export namespace without a
proper driver-specific prefix.

Also, a bunch of the code here seems not so well thought. It was fine
for an internal interface, but it doesn't look so good as a common
wrapper. Please consider defining a sensible common code module
interface instead.

At least each function that is being exported should get a kerneldoc.

Last, but not least, please use EXPORT_SYMBOL_GPL.

> +
> +/*
> + * Helper to prepare DMA descriptors for configuring registers
> + * before reading a NAND page.
> + */
> +void config_nand_page_read(struct nand_chip *chip)
> +{
> +       struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> +
> +       write_reg_dma(nandc, NAND_ADDR0, 2, 0);
> +       write_reg_dma(nandc, NAND_DEV0_CFG0, 3, 0);
> +       if (!nandc->props->qpic_v2)
> +               write_reg_dma(nandc, NAND_EBI2_ECC_BUF_CFG, 1, 0);
> +       write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1, 0);
> +       write_reg_dma(nandc, NAND_ERASED_CW_DETECT_CFG, 1,
> +                     NAND_ERASED_CW_SET | NAND_BAM_NEXT_SGL);
> +}
> +EXPORT_SYMBOL(config_nand_page_read);
> +
> +/* Frees the BAM transaction memory */
> +void free_bam_transaction(struct qcom_nand_controller *nandc)
> +{
> +       struct bam_transaction *bam_txn = nandc->bam_txn;
> +
> +       devm_kfree(nandc->dev, bam_txn);

devm_kfree is usually a bad sign. Either the devm_kfree should be
dropped (because the memory area is allocated only during probe / init
and doesn't need to be freed manually) or use kalloc/kfree directly
without devres wrapping.

> +}
> +EXPORT_SYMBOL(free_bam_transaction);
> +

[skipped the rest]

> --
> 2.34.1
>
>


--
With best wishes
Dmitry