From: "Arnd Bergmann" <arnd@arndb.de>
To: "Brad Larson" <blarson@amd.com>, linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org,
"linux-mmc @ vger . kernel . org" <linux-mmc@vger.kernel.org>,
linux-spi@vger.kernel.org,
"Adrian Hunter" <adrian.hunter@intel.com>,
alcooperx@gmail.com,
"Andy Shevchenko" <andy.shevchenko@gmail.com>,
brendan.higgins@linux.dev,
"Brian Norris" <briannorris@chromium.org>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Conor Dooley" <conor+dt@kernel.org>,
"David Gow" <davidgow@google.com>,
gsomlo@gmail.com, "Greg Ungerer" <gerg@linux-m68k.org>,
"Hal Feng" <hal.feng@starfivetech.com>,
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"Emil Renner Berthing" <kernel@esmil.dk>,
"Krzysztof Kozlowski" <krzk@kernel.org>,
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"Mark Brown" <broonie@kernel.org>,
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"Tom Lendacky" <thomas.lendacky@amd.com>,
"Tony Huang" <tonyhuang.sunplus@gmail.com>,
"Ulf Hansson" <ulf.hansson@linaro.org>,
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"Will Deacon" <will@kernel.org>,
"Yinbo Zhu" <zhuyinbo@loongson.cn>,
devicetree@vger.kernel.org
Subject: Re: [PATCH v14 8/8] soc: amd: Add support for AMD Pensando SoC Controller
Date: Tue, 16 May 2023 13:03:01 +0200 [thread overview]
Message-ID: <bc5118f2-8982-46ff-bc75-d0c71475e909@app.fastmail.com> (raw)
In-Reply-To: <20230515181606.65953-9-blarson@amd.com>
On Mon, May 15, 2023, at 20:16, Brad Larson wrote:
> The Pensando SoC controller is a SPI connected companion device
> that is present in all Pensando SoC board designs. The essential
> board management registers are accessed on chip select 0 with
> board mgmt IO support accessed using additional chip selects.
>
> Signed-off-by: Brad Larson <blarson@amd.com>
Hi Brad,
I'm sorry I wasn't paying enough attention to this driver as the
past 13 revisions went by.
> v10 changes:
> - Different driver implementation specific to this Pensando controller device.
> - Moved to soc/amd directory under new name based on guidance. This driver is
> of no use to any design other than all Pensando SoC based cards.
> - Removed use of builtin_driver, can be built as a module.
it looks like this was a fundamental change that I failed to see.
> +# SPDX-License-Identifier: GPL-2.0-only
> +menu "AMD Pensando SoC drivers"
> +
> +config AMD_PENSANDO_CTRL
> + tristate "AMD Pensando SoC Controller"
> + depends on SPI_MASTER=y
> + depends on (ARCH_PENSANDO && OF) || COMPILE_TEST
> + default ARCH_PENSANDO
> + select REGMAP_SPI
> + select MFD_SYSCON
> + help
> + Enables AMD Pensando SoC controller device support. This is a SPI
> + attached companion device in all Pensando SoC board designs which
> + provides essential board control/status registers and management IO
> + support.
So generally speaking, I don't want custom user interfaces in
drivers/soc. It looks like this one has internal interfaces for
a reset controller and the regmap, so those parts are fine, but
I'm confused about the purpose of the ioctl interface:
> +static long
> +penctrl_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> +{
> + if (num_msgs > 1) {
> + msg++;
> + if (msg->len > PENCTRL_MAX_MSG_LEN) {
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> + t[1].rx_buf = rx_buf;
> + t[1].len = msg->len;
> + }
> + spi_message_init_with_transfers(&m, t, num_msgs);
This seems to be just a passthrough of user space messages, which
is what the spidev driver already provides, but using a different
ioctl interface. I don't really want any user-level interfaces
in drivers/soc as a rule, but having one that duplicates existing
functionality seems particularly wrong.
Can you explain what the purpose is? Is this about serializing
access between the in-kernel reset control and the user-side
access?
Also, can you explain why this needs a low-lever user interface
in the first place, rather than something that can be expressed
using high-level abstractions as you already do with the reset
control?
All of the above should be part of the changelog text to get a
driver like this merged. I don't think we can get a quick
solution here though, so maybe you can start by removing the
ioctl side and having the rest of the driver in drivers/reset?
Arnd
next prev parent reply other threads:[~2023-05-16 11:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-15 18:15 [PATCH v14 0/8] Support AMD Pensando Elba SoC Brad Larson
2023-05-15 18:15 ` [PATCH v14 1/8] dt-bindings: arm: add AMD Pensando boards Brad Larson
2023-05-15 18:16 ` [PATCH v14 2/8] dt-bindings: spi: cdns: Add compatible for AMD Pensando Elba SoC Brad Larson
2023-05-16 15:18 ` Mark Brown
2023-05-15 18:16 ` [PATCH v14 3/8] dt-bindings: soc: amd: amd,pensando-elba-ctrl: Add Pensando SoC Controller Brad Larson
2023-05-15 18:16 ` [PATCH v14 4/8] MAINTAINERS: Add entry for AMD PENSANDO Brad Larson
2023-05-15 18:16 ` [PATCH v14 5/8] arm64: Add config for AMD Pensando SoC platforms Brad Larson
2023-05-15 18:16 ` [PATCH v14 6/8] arm64: dts: Add AMD Pensando Elba SoC support Brad Larson
2023-05-16 7:17 ` Krzysztof Kozlowski
2023-05-16 7:54 ` Michal Simek
2023-05-23 19:28 ` Brad Larson
2023-05-24 11:52 ` Geert Uytterhoeven
2023-05-30 22:03 ` Brad Larson
2023-05-31 13:09 ` Geert Uytterhoeven
2023-06-05 23:52 ` Brad Larson
2023-05-15 18:16 ` [PATCH v14 7/8] spi: cadence-quadspi: Add compatible for AMD Pensando Elba SoC Brad Larson
2023-05-15 18:16 ` [PATCH v14 8/8] soc: amd: Add support for AMD Pensando SoC Controller Brad Larson
2023-05-15 21:05 ` Andy Shevchenko
2023-05-23 2:12 ` Brad Larson
2023-05-16 5:19 ` Mahapatra, Amit Kumar
2023-05-16 7:36 ` Michal Simek
2023-05-17 11:14 ` Geert Uytterhoeven
2023-05-16 8:45 ` kernel test robot
2023-05-16 11:03 ` Arnd Bergmann [this message]
2023-05-23 22:11 ` Brad Larson
2023-05-24 12:41 ` Arnd Bergmann
2023-08-07 22:17 ` Brad Larson
2023-05-16 7:14 ` [PATCH v14 0/8] Support AMD Pensando Elba SoC Krzysztof Kozlowski
2023-05-17 14:43 ` (subset) " Mark Brown
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