linux-kernel - Re: [PATCH 2/4] peci: Add peci-npcm controller driver

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Message-ID: <dfda43af-e9b4-85bf-e165-02127e02fbf0@molgen.mpg.de>
Date:   Thu, 20 Jul 2023 08:20:05 +0200
From:   Paul Menzel <pmenzel@...gen.mpg.de>
To:     Iwona Winiarska <iwona.winiarska@...el.com>
Cc:     openbmc@...ts.ozlabs.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, Conor Dooley <conor+dt@...nel.org>,
        Tyrone Ting <warp5tw@...il.com>,
        Benjamin Fair <benjaminfair@...gle.com>,
        Avi Fishman <avifishman70@...il.com>,
        Patrick Venture <venture@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Tomer Maimon <tmaimon77@...il.com>
Subject: Re: [PATCH 2/4] peci: Add peci-npcm controller driver

Dear Iwona,


Am 20.07.23 um 00:08 schrieb Iwona Winiarska:
> From: Tomer Maimon <tmaimon77@...il.com>
> 
> Add support for Nuvoton NPCM BMC hardware to the Platform Environment
> Control Interface (PECI) subsystem.

Please elaborate on the implementation, and document the used datasheets.

Additionally, please document how you tested this.

> Signed-off-by: Tomer Maimon <tmaimon77@...il.com>
> Signed-off-by: Tyrone Ting <warp5tw@...il.com>
> Co-developed-by: Iwona Winiarska <iwona.winiarska@...el.com>
> Signed-off-by: Iwona Winiarska <iwona.winiarska@...el.com>
> ---
>   drivers/peci/controller/Kconfig     |  16 ++
>   drivers/peci/controller/Makefile    |   1 +
>   drivers/peci/controller/peci-npcm.c | 298 ++++++++++++++++++++++++++++
>   3 files changed, 315 insertions(+)
>   create mode 100644 drivers/peci/controller/peci-npcm.c
> 
> diff --git a/drivers/peci/controller/Kconfig b/drivers/peci/controller/Kconfig
> index 2fc5e2abb74a..4f9c245ad042 100644
> --- a/drivers/peci/controller/Kconfig
> +++ b/drivers/peci/controller/Kconfig
> @@ -16,3 +16,19 @@ config PECI_ASPEED
>   
>   	  This driver can also be built as a module. If so, the module will
>   	  be called peci-aspeed.
> +
> +config PECI_NPCM
> +	tristate "Nuvoton NPCM PECI support"
> +	depends on ARCH_NPCM || COMPILE_TEST
> +	depends on OF
> +	select REGMAP_MMIO
> +	help
> +	  This option enables PECI controller driver for Nuvoton NPCM7XX
> +	  and NPCM8XX SoCs. It allows BMC to discover devices connected
> +	  to it and communicate with them using PECI protocol.
> +
> +	  Say Y here if you want support for the Platform Environment Control
> +	  Interface (PECI) bus adapter driver on the Nuvoton NPCM SoCs.
> +
> +	  This support is also available as a module. If so, the module
> +	  will be called peci-npcm.
> diff --git a/drivers/peci/controller/Makefile b/drivers/peci/controller/Makefile
> index 022c28ef1bf0..e247449bb423 100644
> --- a/drivers/peci/controller/Makefile
> +++ b/drivers/peci/controller/Makefile
> @@ -1,3 +1,4 @@
>   # SPDX-License-Identifier: GPL-2.0-only
>   
>   obj-$(CONFIG_PECI_ASPEED)	+= peci-aspeed.o
> +obj-$(CONFIG_PECI_NPCM)		+= peci-npcm.o
> diff --git a/drivers/peci/controller/peci-npcm.c b/drivers/peci/controller/peci-npcm.c
> new file mode 100644
> index 000000000000..3647e3628a17
> --- /dev/null
> +++ b/drivers/peci/controller/peci-npcm.c
> @@ -0,0 +1,298 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2019 Nuvoton Technology corporation.

No dot/period at the end.

[…]

> +static int npcm_peci_xfer(struct peci_controller *controller, u8 addr, struct peci_request *req)
> +{
> +	struct npcm_peci *priv = dev_get_drvdata(controller->dev.parent);
> +	unsigned long timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
> +	unsigned int msg_rd;
> +	u32 cmd_sts;
> +	int i, ret;
> +
> +	/* Check command sts and bus idle state */
> +	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
> +				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
> +				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
> +				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
> +	if (ret)
> +		return ret; /* -ETIMEDOUT */
> +
> +	spin_lock_irq(&priv->lock);
> +	reinit_completion(&priv->xfer_complete);
> +
> +	regmap_write(priv->regmap, NPCM_PECI_ADDR, addr);
> +	regmap_write(priv->regmap, NPCM_PECI_RD_LENGTH, NPCM_PECI_WR_LEN_MASK & req->rx.len);
> +	regmap_write(priv->regmap, NPCM_PECI_WR_LENGTH, NPCM_PECI_WR_LEN_MASK & req->tx.len);
> +
> +	if (req->tx.len) {
> +		regmap_write(priv->regmap, NPCM_PECI_CMD, req->tx.buf[0]);
> +
> +		for (i = 0; i < (req->tx.len - 1); i++)
> +			regmap_write(priv->regmap, NPCM_PECI_DAT_INOUT(i), req->tx.buf[i + 1]);
> +	}
> +
> +#if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
> +	dev_dbg(priv->dev, "addr : %#02x, tx.len : %#02x, rx.len : %#02x\n",
> +		addr, req->tx.len, req->rx.len);
> +	print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req->tx.len);
> +#endif

The preprocessor guards are not needed, as it’s taken care of in 
`include/linux/printk.h`. Also in other parts of the patch.

[…]

> +module_platform_driver(npcm_peci_driver);
> +
> +MODULE_AUTHOR("Tomer Maimon <tomer.maimon@...oton.com>");
> +MODULE_DESCRIPTION("NPCM PECI driver");
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(PECI);

Also add an entry to `MAINTAINERS`, if Tomer is going to be the maintainer?


Kind regards,

Paul