Date: Tue, 21 May 2024 11:52:35 +0200
From: neil.armstrong@...aro.org
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konrad.dybcio@...aro.org>,
 Loic Poulain <loic.poulain@...aro.org>, Kalle Valo <kvalo@...nel.org>,
 Mathieu Poirier <mathieu.poirier@...aro.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 wcn36xx@...ts.infradead.org, linux-wireless@...r.kernel.org,
 linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
 Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH 01/12] soc: qcom: add firmware name helper

On 21/05/2024 11:45, Dmitry Baryshkov wrote:
> Qualcomm platforms have different sets of the firmware files, which
> differ from platform to platform (and from board to board, due to the
> embedded signatures). Rather than listing all the firmware files,
> including full paths, in the DT, provide a way to determine firmware
> path based on the root DT node compatible.

Ok this looks quite over-engineered but necessary to handle the legacy,
but I really think we should add a way to look for a board-specific path
first and fallback to those SoC specific paths.

Neil

> 
> Suggested-by: Arnd Bergmann <arnd@...db.de>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
>   drivers/soc/qcom/Kconfig           |  5 +++
>   drivers/soc/qcom/Makefile          |  1 +
>   drivers/soc/qcom/qcom_fw_helper.c  | 86 ++++++++++++++++++++++++++++++++++++++
>   include/linux/soc/qcom/fw_helper.h | 10 +++++
>   4 files changed, 102 insertions(+)
> 
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 5af33b0e3470..b663774d65f8 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -62,6 +62,11 @@ config QCOM_MDT_LOADER
>   	tristate
>   	select QCOM_SCM
>   
> +config QCOM_FW_HELPER
> +	tristate "NONE FW HELPER"
> +	help
> +	  Helpers to return platform-specific location for the firmware files.
> +
>   config QCOM_OCMEM
>   	tristate "Qualcomm On Chip Memory (OCMEM) driver"
>   	depends on ARCH_QCOM
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index ca0bece0dfff..e612bee5b955 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
>   obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
>   obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
>   obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
> +obj-$(CONFIG_QCOM_FW_HELPER)	+= qcom_fw_helper.o
>   obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
>   obj-$(CONFIG_QCOM_PDR_HELPERS)	+= pdr_interface.o
>   obj-$(CONFIG_QCOM_PMIC_GLINK)	+= pmic_glink.o
> diff --git a/drivers/soc/qcom/qcom_fw_helper.c b/drivers/soc/qcom/qcom_fw_helper.c
> new file mode 100644
> index 000000000000..13123c2514b8
> --- /dev/null
> +++ b/drivers/soc/qcom/qcom_fw_helper.c
> @@ -0,0 +1,86 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Qualcomm Firmware loading data
> + *
> + * Copyright (C) 2024 Linaro Ltd
> + */
> +
> +#include <linux/cleanup.h>
> +#include <linux/device.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/soc/qcom/fw_helper.h>
> +
> +static DEFINE_MUTEX(qcom_fw_mutex);
> +static const char *fw_path;
> +
> +static const struct of_device_id qcom_fw_paths[] = {
> +	/* device-specific entries */
> +	{ .compatible = "thundercomm,db845c", .data = "qcom/sdm845/Thundercomm/db845c", },
> +	{ .compatible = "qcom,qrb5165-rb5", .data = "qcom/sm8250/Thundercomm/RB5", },
> +	/* SoC default entries */
> +	{ .compatible = "qcom,apq8016", .data = "qcom/apq8016", },
> +	{ .compatible = "qcom,apq8096", .data = "qcom/apq8096", },
> +	{ .compatible = "qcom,sdm845", .data = "qcom/sdm845", },
> +	{ .compatible = "qcom,sm8250", .data = "qcom/sm8250", },
> +	{ .compatible = "qcom,sm8350", .data = "qcom/sm8350", },
> +	{ .compatible = "qcom,sm8450", .data = "qcom/sm8450", },
> +	{ .compatible = "qcom,sm8550", .data = "qcom/sm8550", },
> +	{ .compatible = "qcom,sm8650", .data = "qcom/sm8650", },
> +	{},
> +};
> +
> +static int qcom_fw_ensure_init(void)
> +{
> +	const struct of_device_id *match;
> +	struct device_node *root;
> +
> +	if (fw_path)
> +		return 0;
> +
> +	root = of_find_node_by_path("/");
> +	if (!root)
> +		return -ENODEV;
> +
> +	match = of_match_node(qcom_fw_paths, root);
> +	of_node_put(root);
> +	if (!match || !match->data) {
> +		pr_notice("Platform not supported by qcom_fw_helper\n");
> +		return -ENODEV;
> +	}
> +
> +	fw_path = match->data;
> +
> +	return 0;
> +}
> +
> +const char *qcom_get_board_fw(const char *firmware)
> +{
> +	if (strchr(firmware, '/'))
> +		return kstrdup(firmware, GFP_KERNEL);
> +
> +	scoped_guard(mutex, &qcom_fw_mutex) {
> +		if (!qcom_fw_ensure_init())
> +			return kasprintf(GFP_KERNEL, "%s/%s", fw_path, firmware);
> +	}
> +
> +	return kstrdup(firmware, GFP_KERNEL);
> +}
> +EXPORT_SYMBOL_GPL(qcom_get_board_fw);
> +
> +const char *devm_qcom_get_board_fw(struct device *dev, const char *firmware)
> +{
> +	if (strchr(firmware, '/'))
> +		return devm_kstrdup(dev, firmware, GFP_KERNEL);
> +
> +	scoped_guard(mutex, &qcom_fw_mutex) {
> +		if (!qcom_fw_ensure_init())
> +			return devm_kasprintf(dev, GFP_KERNEL, "%s/%s", fw_path, firmware);
> +	}
> +
> +	return devm_kstrdup(dev, firmware, GFP_KERNEL);
> +}
> +EXPORT_SYMBOL_GPL(devm_qcom_get_board_fw);
> +
> +MODULE_DESCRIPTION("Firmware helpers for Qualcomm devices");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/soc/qcom/fw_helper.h b/include/linux/soc/qcom/fw_helper.h
> new file mode 100644
> index 000000000000..755645386bba
> --- /dev/null
> +++ b/include/linux/soc/qcom/fw_helper.h
> @@ -0,0 +1,10 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __QCOM_FW_HELPER_H__
> +#define __QCOM_FW_HELPER_H__
> +
> +struct device;
> +
> +const char *qcom_get_board_fw(const char *firmware);
> +const char *devm_qcom_get_board_fw(struct device *dev, const char *firmware);
> +
> +#endif
> 

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