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Message-ID: <2caa16e0-81bb-7d6a-d727-89e2cd0b858d@acm.org>
Date:   Thu, 28 Jul 2022 11:13:02 -0700
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Subject: Re: [PATCH V2] scsi: ufs: Get boot device storage type from command
 line
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To:     Chetan C R <quic_cchinnad@quicinc.com>
Cc:     jejb@linux.ibm.com, linux-kernel@vger.kernel.org,
        linux-scsi@vger.kernel.org
References: <1659029442-19135-1-git-send-email-quic_cchinnad@quicinc.com>
 <1659029442-19135-2-git-send-email-quic_cchinnad@quicinc.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <1659029442-19135-2-git-send-email-quic_cchinnad@quicinc.com>
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On 7/28/22 10:30, Chetan C R wrote:
> Get the boot device storage type by reading it from
> kernel command line arguments and export the same
> information to ufs modules.
> 
> Signed-off-by: Chetan C R <quic_cchinnad@quicinc.com>
> ---
>   drivers/ufs/host/Kconfig       | 10 ++++++++
>   drivers/ufs/host/Makefile      |  1 +
>   drivers/ufs/host/ufs-cmdline.c | 54 ++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 65 insertions(+)
>   create mode 100644 drivers/ufs/host/ufs-cmdline.c
> 
> diff --git a/drivers/ufs/host/Kconfig b/drivers/ufs/host/Kconfig
> index 8259022..02fe817 100644
> --- a/drivers/ufs/host/Kconfig
> +++ b/drivers/ufs/host/Kconfig
> @@ -68,6 +68,16 @@ config SCSI_UFS_QCOM
>   	  Select this if you have UFS controller on QCOM chipset.
>   	  If unsure, say N.
>   
> +config UFS_QCOM_CMDLINE
> +	bool "Get the boot device type from kernel command line for Qcom devices"
> +	default y if ARCH_QCOM
> +	help
> +	  This selects the support of getting the boot device storage type
> +	  from kernel command line arguments and export this information
> +	  to the Qcom UFS controller platform driver.
> +
> +	  If unsure, say N.
> +
>   config SCSI_UFS_MEDIATEK
>   	tristate "Mediatek specific hooks to UFS controller platform driver"
>   	depends on SCSI_UFSHCD_PLATFORM && ARCH_MEDIATEK
> diff --git a/drivers/ufs/host/Makefile b/drivers/ufs/host/Makefile
> index e4be542..a9463f1 100644
> --- a/drivers/ufs/host/Makefile
> +++ b/drivers/ufs/host/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_SCSI_UFS_CDNS_PLATFORM) += cdns-pltfrm.o
>   obj-$(CONFIG_SCSI_UFS_QCOM) += ufs_qcom.o
>   ufs_qcom-y += ufs-qcom.o
>   ufs_qcom-$(CONFIG_SCSI_UFS_CRYPTO) += ufs-qcom-ice.o
> +obj-$(CONFIG_UFS_QCOM_CMDLINE)          += ufs-cmdline.o
>   obj-$(CONFIG_SCSI_UFS_EXYNOS) += ufs-exynos.o
>   obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
>   obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
> diff --git a/drivers/ufs/host/ufs-cmdline.c b/drivers/ufs/host/ufs-cmdline.c
> new file mode 100644
> index 0000000..408755c
> --- /dev/null
> +++ b/drivers/ufs/host/ufs-cmdline.c
> @@ -0,0 +1,54 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/printk.h>
> +#include <linux/string.h>
> +
> +#ifdef CONFIG_BOOT_CONFIG
> +#include <linux/bootconfig.h>
> +#endif
> +
> +#define ANDROID_BOOT_DEV_MAX_V3    30
> +
> +static char android_boot_dev_v3[ANDROID_BOOT_DEV_MAX_V3];
> +static const char *android_boot_dev_v4;
> +
> +const char *get_storage_boot_device(void)
> +{
> +	if (android_boot_dev_v4 && strlen(android_boot_dev_v4))
> +		return android_boot_dev_v4;
> +
> +	else if (strlen(android_boot_dev_v3))
> +		return android_boot_dev_v3;
> +
> +	pr_err("Not able to get Bootconfig or Kernel command line param\n");
> +	return NULL;
> +};
> +EXPORT_SYMBOL_GPL(get_storage_boot_device);
> +
> +/* boot image header version 3 android boot device type */
> +static int __init get_android_boot_dev_v3(char *str)
> +{
> +	strscpy(android_boot_dev_v3, str, ANDROID_BOOT_DEV_MAX_V3);
> +	return 1;
> +}
> +__setup("androidboot.bootdevice=", get_android_boot_dev_v3);
> +
> +#ifdef CONFIG_BOOT_CONFIG
> +/* boot image header version 4 android boot device type */
> +static int __init get_android_boot_dev_v4(void)
> +{
> +	struct xbc_node *vnode = NULL;
> +
> +	android_boot_dev_v4 = xbc_find_value("androidboot.bootdevice", &vnode);
> +
> +	if (vnode && xbc_node_is_array(vnode))
> +		xbc_array_for_each_value(vnode, android_boot_dev_v4);
> +
> +	return 0;
> +}
> +fs_initcall(get_android_boot_dev_v4);
> +#endif

I see a similar problem with this patch as with the previous version of 
this patch: if CONFIG_SCSI_UFSHCD=m, __setup() will be an empty macro 
and hence the androidboot.bootdevice parameter won't be parsed.

Bart.