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Subject: Re: [PATCH V10 2/2] scsi: ufs: Add configfs support for UFS
 provisioning
To:     Sayali Lokhande <sayalil@codeaurora.org>, subhashj@codeaurora.org,
        cang@codeaurora.org, vivek.gautam@codeaurora.org,
        rnayak@codeaurora.org, vinholikatti@gmail.com,
        jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
        asutoshd@codeaurora.org, evgreen@chromium.org,
        riteshh@codeaurora.org
Cc:     linux-scsi@vger.kernel.org,
        open list <linux-kernel@vger.kernel.org>
References: <1535088810-20989-1-git-send-email-sayalil@codeaurora.org>
 <1535088810-20989-3-git-send-email-sayalil@codeaurora.org>
 <5d2a6dea-e524-fca7-3c4b-a45bc9e6516a@intel.com>
 <8ee0372b-d930-208d-520b-5a38642a2844@codeaurora.org>
 <a8405e52-ab28-f7ad-e150-4a633d0ad4bc@intel.com>
 <49d1be22-b85d-abfb-3b4e-d8b4b7176d14@codeaurora.org>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
Message-ID: <e68f1f7c-4692-744c-6049-abd3061f398b@intel.com>
Date:   Tue, 28 Aug 2018 15:06:40 +0300
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On 28/08/18 14:40, Sayali Lokhande wrote:
> 
> On 8/28/2018 4:56 PM, Adrian Hunter wrote:
>> On 28/08/18 13:23, Sayali Lokhande wrote:
>>> Hi Adrian,
>>>
>>> On 8/24/2018 2:15 PM, Adrian Hunter wrote:
>>>> On 24/08/18 08:33, Sayali Lokhande wrote:
>>>>> This patch adds configfs support to provision UFS device at
>>>>> runtime. This feature can be primarily useful in factory or
>>>>> assembly line as some devices may be required to be configured
>>>>> multiple times during initial system development phase.
>>>>> Configuration Descriptors can be written multiple times until
>>>>> bConfigDescrLock attribute is zero.
>>>>>
>>>>> Configuration descriptor buffer consists of Device and Unit
>>>>> descriptor configurable parameters which are parsed from vendor
>>>>> specific provisioning file and then passed via configfs node at
>>>>> runtime to provision ufs device.
>>>>> CONFIG_CONFIGFS_FS needs to be enabled for using this feature.
>>>>>
>>>>> Usage:
>>>>> 1) To read current configuration descriptor :
>>>>>      cat /config/XXXX.ufshc/ufs_provision
>>>>> 2) To provision ufs device:
>>>>>      echo <config_desc_buf> > /config/XXXX.ufshc/ufs_provision
>>>>>
>>>>> Signed-off-by: Sayali Lokhande <sayalil@codeaurora.org>
>>>>> ---
>>>>>    Documentation/ABI/testing/configfs-driver-ufs |  18 +++
>>>>>    drivers/scsi/ufs/Kconfig                      |  10 ++
>>>>>    drivers/scsi/ufs/Makefile                     |   1 +
>>>>>    drivers/scsi/ufs/ufs-configfs.c               | 155
>>>>> ++++++++++++++++++++++++++
>>>>>    drivers/scsi/ufs/ufshcd.c                     |   3 +-
>>>>>    drivers/scsi/ufs/ufshcd.h                     |  17 +++
>>>>>    6 files changed, 203 insertions(+), 1 deletion(-)
>>>>>    create mode 100644 Documentation/ABI/testing/configfs-driver-ufs
>>>>>    create mode 100644 drivers/scsi/ufs/ufs-configfs.c
>>>>>
>>>>> diff --git a/Documentation/ABI/testing/configfs-driver-ufs
>>>>> b/Documentation/ABI/testing/configfs-driver-ufs
>>>>> new file mode 100644
>>>>> index 0000000..eeee499c
>>>>> --- /dev/null
>>>>> +++ b/Documentation/ABI/testing/configfs-driver-ufs
>>>>> @@ -0,0 +1,18 @@
>>>>> +What:        /config/ufshcd/ufs_provision
>>>> You are using the device name as the config subsystem name, so this is
>>>> really:
>>>>
>>>>      What:        /config/*/ufs_provision
>>> Agree. Will update.
>>>>> +Date:        Jun 2018
>>>>> +KernelVersion:    4.14
>>>> 4.19 maybe
>>> Done.
>>>>> +Description:
>>>>> +        This file shows the current ufs configuration descriptor set in
>>>>> device.
>>>> It is only the first config descriptor though isn't it?  There is no
>>>> support
>>>> for the other 3.  Shouldn't we support config descriptors fully?
>>> Yes, we should support config descriptors fully. My current implementation
>>> only supports config desc (index = 00h).
>>> I m thinking I can add separate "index" field along with "ufs_provision"
>>> field and can use this index (instead of hard coding to 0)
>>> to write repective config_desc. In this way, we should first set the "index"
>>> and then read/write to "ufs_provision".
>>> Let me know if you have any concern with this approach ?
>> One file for each config descriptor would seem more normal.
> I can make separate file for each config descriptor index(say
> ufs_provision_0/1/2/3), but still show() and store() api's can remain common.
> Will try it out and update.
>>>>> +        This can be used to provision ufs device if bConfigDescrLock
>>>>> is 0.
>>>>> +        For more details, refer 14.1.6.3 Configuration Descriptor and
>>>>> +        Table 14-12 - Unit Descriptor configurable parameters from specs
>>>>> for
>>>>> +        description of each configuration descriptor parameter.
>>>>> +        Configuration descriptor buffer needs to be passed in space
>>>>> separated
>>>>> +        format specificied as below:
>>>> specificied -> specified
>>> Done
>>>>> +        echo <bLength> <bDescriptorIDN> <bConfDescContinue> <bBootEnable>
>>>>> +        <bDescrAccessEn> <bInitPowerMode> <bHighPriorityLUN>
>>>>> +        <bSecureRemovalType> <bInitActiveICCLevel> <wPeriodicRTCUpdate>
>>>>> +        <0Bh:0Fh_ReservedAs_0> <bLUEnable> <bBootLunID> <bLUWriteProtect>
>>>>> +        <bMemoryType> <dNumAllocUnits> <bDataReliability>
>>>>> <bLogicalBlockSize>
>>>>> +        <bProvisioningType> <wContextCapabilities> <0Dh:0Fh_ReservedAs_0>
>>>> This format is not exactly correct anymore because each byte has to be
>>>> represented separately.  Also theoretically it can be change, so maybe
>>>> better just to refer the user to the UFS specification.
>>> Agree. Will update to just refer to UFS spec (for Config_desc format).
>>>
>>>>> +        > /config/XXXX.ufshc/ufs_provision
>>>>> diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
>>>>> index e27b4d4..a9a0a58 100644
>>>>> --- a/drivers/scsi/ufs/Kconfig
>>>>> +++ b/drivers/scsi/ufs/Kconfig
>>>>> @@ -100,3 +100,13 @@ config SCSI_UFS_QCOM
>>>>>            Select this if you have UFS controller on QCOM chipset.
>>>>>          If unsure, say N.
>>>>> +
>>>>> +config UFS_PROVISION
>>>>> +    tristate "Runtime UFS Provisioning support"
>>>>> +    depends on SCSI_UFSHCD && CONFIGFS_FS
>>>>> +    help
>>>>> +      This enables runtime UFS provisioning support. This can be used
>>>>> +      primarily during assembly line as some devices may be required to
>>>>> +      be configured multiple times during initial development phase.
>>>>> +
>>>>> +      If unsure, say N.
>>>>> diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
>>>>> index 918f579..00110ea 100644
>>>>> --- a/drivers/scsi/ufs/Makefile
>>>>> +++ b/drivers/scsi/ufs/Makefile
>>>>> @@ -5,5 +5,6 @@ obj-$(CONFIG_SCSI_UFS_DWC_TC_PLATFORM) +=
>>>>> tc-dwc-g210-pltfrm.o ufshcd-dwc.o tc-d
>>>>>    obj-$(CONFIG_SCSI_UFS_QCOM) += ufs-qcom.o
>>>>>    obj-$(CONFIG_SCSI_UFSHCD) += ufshcd-core.o
>>>>>    ufshcd-core-objs := ufshcd.o ufs-sysfs.o
>>>>> +obj-$(CONFIG_UFS_PROVISION) += ufs-configfs.o
>>>>>    obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
>>>>>    obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
>>>>> diff --git a/drivers/scsi/ufs/ufs-configfs.c
>>>>> b/drivers/scsi/ufs/ufs-configfs.c
>>>>> new file mode 100644
>>>>> index 0000000..74563a4
>>>>> --- /dev/null
>>>>> +++ b/drivers/scsi/ufs/ufs-configfs.c
>>>>> @@ -0,0 +1,155 @@
>>>>> +// SPDX-License-Identifier: GPL-2.0+
>>>>> +// Copyright (c) 2018, Linux Foundation.
>>>>> +
>>>>> +#include <linux/configfs.h>
>>>>> +#include <linux/err.h>
>>>>> +#include <linux/string.h>
>>>>> +
>>>>> +#include "ufs.h"
>>>>> +#include "ufshcd.h"
>>>>> +
>>>>> +static inline struct ufs_hba *config_item_to_hba(struct config_item
>>>>> *item)
>>>>> +{
>>>>> +    struct config_group *group = to_config_group(item);
>>>>> +    struct configfs_subsystem *subsys = to_configfs_subsystem(group);
>>>>> +    struct ufs_hba *hba = container_of(subsys, struct ufs_hba, subsys);
>>>>> +
>>>>> +    return subsys ? hba : NULL;
>>>>> +}
>>>>> +
>>>>> +static ssize_t ufs_provision_show(struct config_item *item, char *buf)
>>>>> +{
>>>>> +    u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
>>>> Is it really ok to hard-code the descriptor size?
>>> I will use ufshcd_read_desc_length() api for each index as required. Will
>>> remove this hard-code.
>> Alternatively, I see there is already hba->desc_size.conf_desc
> hba->desc_size.conf_desc is actually size for index 0. I thought what if
> desc size various per index.
> So better to read for each index. What say ?

Based on the 'B' and 'L' values defined in the spec., all configuration
descriptors have the same length.

>>
>>>>> +    int desc_buf_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
>>>>> +    int i, ret, curr_len = 0;
>>>>> +    struct ufs_hba *hba = config_item_to_hba(item);
>>>>> +
>>>>> +    ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
>>>>> +        QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &desc_buf_len);
>>>>> +
>>>>> +    if (ret)
>>>>> +        return ret;
>>>>> +
>>>>> +    for (i = 0; i < desc_buf_len; i++)
>>>>> +        curr_len += snprintf((buf + curr_len), (PAGE_SIZE - curr_len),
>>>>> +                "0x%x ", desc_buf[i]);
>>>>> +
>>>>> +    return curr_len;
>>>>> +}
>>>>> +
>>>>> +ssize_t ufshcd_desc_configfs_store(struct ufs_hba *hba,
>>>>> +        const char *buf, size_t count)
>>>>> +{
>>>>> +    char *strbuf;
>>>>> +    char *strbuf_copy;
>>>>> +    u8 desc_buf[QUERY_DESC_CONFIGURATION_DEF_SIZE] = {0};
>>>>> +    int desc_buf_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
>>>>> +    char *token;
>>>>> +    int i, ret, value;
>>>>> +    u32 config_desc_lock = 0;
>>>>> +
>>>>> +    /* reserve one byte for null termination */
>>>>> +    strbuf = kmalloc(count + 1, GFP_KERNEL);
>>>>> +    if (!strbuf)
>>>>> +        return -ENOMEM;
>>>>> +
>>>>> +    strbuf_copy = strbuf;
>>>>> +    strlcpy(strbuf, buf, count + 1);
>>>>> +
>>>>> +    /* Just return if bConfigDescrLock is already set */
>>>>> +    ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
>>>>> +        QUERY_ATTR_IDN_CONF_DESC_LOCK, 0, 0, &config_desc_lock);
>>>>> +    if (ret)
>>>>> +        goto out;
>>>>> +
>>>>> +    if (config_desc_lock) {
>>>>> +        dev_err(hba->dev, "%s: bConfigDescrLock already set to %u,
>>>>> cannot re-provision device!\n",
>>>>> +        __func__, config_desc_lock);
>>>>> +        ret = -EINVAL;
>>>>> +        goto out;
>>>>> +    }
>>>>> +
>>>>> +    for (i = 0; i < QUERY_DESC_CONFIGURATION_DEF_SIZE; i++) {
>>>>> +        token = strsep(&strbuf, " ");
>>>>> +        if (!token && i)
>>>>> +            break;
>>>>> +
>>>>> +        ret = kstrtoint(token, 0, &value);
>>>>> +        if (ret) {
>>>>> +            dev_err(hba->dev, "%s: kstrtoint failed %d %s\n",
>>>>> +                __func__, ret, token);
>>>>> +            ret = -EINVAL;
>>>>> +            goto out;
>>>>> +        }
>>>>> +        desc_buf[i] = (u8)value;
>>>>> +    }
>>>>> +
>>>>> +    /* Write configuration descriptor to provision ufs */
>>>>> +    ret = ufshcd_query_descriptor_retry(hba,
>>>>> UPIU_QUERY_OPCODE_WRITE_DESC,
>>>>> +        QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &desc_buf_len);
>>>>> +
>>>>> +    if (!ret)
>>>>> +        dev_info(hba->dev, "%s: UFS Provisioning done, reboot now!\n",
>>>> That is not necessarily true - bConfDescContinue might have been used or
>>>> bConfigDescrLock might need to be set.  Better just to say that
>>>> configuration descriptor 0 was written.
>>> Agree. Will update.
>>>>> +        __func__);
>>>>> +
>>>>> +out:
>>>>> +    kfree(strbuf_copy);
>>>>> +    if (ret)
>>>>> +        return ret;
>>>>> +    return count;
>>>>> +}
>>>>> +
>>>>> +static ssize_t ufs_provision_store(struct config_item *item,
>>>>> +        const char *buf, size_t count)
>>>>> +{
>>>>> +    struct ufs_hba *hba = config_item_to_hba(item);
>>>>> +
>>>>> +    return ufshcd_desc_configfs_store(hba, buf, count);
>>>>> +}
>>>>> +
>>>>> +static struct configfs_attribute ufshcd_attr_provision = {
>>>>> +    .ca_name    = "ufs_provision",
>>>>> +    .ca_mode    = 0644,
>>>>> +    .ca_owner    = THIS_MODULE,
>>>>> +    .show        = ufs_provision_show,
>>>>> +    .store        = ufs_provision_store,
>>>>> +};
>>>>> +
>>>>> +static struct configfs_attribute *ufshcd_attrs[] = {
>>>>> +    &ufshcd_attr_provision,
>>>>> +    NULL,
>>>>> +};
>>>>> +
>>>>> +static struct config_item_type ufscfg_type = {
>>>>> +    .ct_attrs    = ufshcd_attrs,
>>>>> +    .ct_owner    = THIS_MODULE,
>>>>> +};
>>>>> +
>>>>> +static struct configfs_subsystem ufscfg_subsys = {
>>>>> +    .su_group = {
>>>>> +        .cg_item = {
>>>>> +            .ci_type = &ufscfg_type,
>>>>> +        },
>>>>> +    },
>>>>> +};
>>>>> +
>>>>> +void ufshcd_configfs_init(struct ufs_hba *hba, const char *name)
>>>>> +{
>>>>> +    int ret;
>>>>> +    struct configfs_subsystem *subsys = &hba->subsys;
>>>>> +
>>>>> +    strncpy(ufscfg_subsys.su_group.cg_item.ci_namebuf, name,
>>>>> strlen(name));
>>>>> +    subsys->su_group = ufscfg_subsys.su_group;
>>>> configfs_subsystem cannot share su_group with other configfs_subsystem i.e
>>>> you are not allowing for there being more than 1 hba
>>> Agree. I think I will have to move above
>>> declarations(ufscfg_subsys/ufscfg_type/ufshcd_attrs) in driver .c/.h file
>>> (to make it per ufs hba/probe).
>>> Will check and update.
>>>>> +    config_group_init(&subsys->su_group);
>>>>> +    mutex_init(&subsys->su_mutex);
>>>>> +    ret = configfs_register_subsystem(subsys);
>>>>> +    if (ret)
>>>>> +        pr_err("Error %d while registering subsystem %s\n",
>>>>> +               ret,
>>>>> +               subsys->su_group.cg_item.ci_namebuf);
>>>>> +}
>>>>> +
>>>>> +void ufshcd_configfs_exit(void)
>>>>> +{
>>>>> +    configfs_unregister_subsystem(&ufscfg_subsys);
>>>>> +}
>>>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>>>> index e01cdc0..32a67b0 100644
>>>>> --- a/drivers/scsi/ufs/ufshcd.c
>>>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>>>> @@ -7711,6 +7711,7 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>>>>>    void ufshcd_remove(struct ufs_hba *hba)
>>>>>    {
>>>>>        ufs_sysfs_remove_nodes(hba->dev);
>>>>> +    ufshcd_configfs_exit();
>>>>>        scsi_remove_host(hba->host);
>>>>>        /* disable interrupts */
>>>>>        ufshcd_disable_intr(hba, hba->intr_mask);
>>>>> @@ -7965,7 +7966,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem
>>>>> *mmio_base, unsigned int irq)
>>>>>          async_schedule(ufshcd_async_scan, hba);
>>>>>        ufs_sysfs_add_nodes(hba->dev);
>>>>> -
>>>>> +    ufshcd_configfs_init(hba, dev_name(hba->dev));
>>>>>        return 0;
>>>>>      out_remove_scsi_host:
>>>>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>>>>> index 45013b6..2275032 100644
>>>>> --- a/drivers/scsi/ufs/ufshcd.h
>>>>> +++ b/drivers/scsi/ufs/ufshcd.h
>>>>> @@ -37,6 +37,7 @@
>>>>>    #ifndef _UFSHCD_H
>>>>>    #define _UFSHCD_H
>>>>>    +#include <linux/configfs.h>
>>>>>    #include <linux/module.h>
>>>>>    #include <linux/kernel.h>
>>>>>    #include <linux/init.h>
>>>>> @@ -515,6 +516,9 @@ struct ufs_hba {
>>>>>          struct Scsi_Host *host;
>>>>>        struct device *dev;
>>>>> +#ifdef CONFIG_UFS_PROVISION
>>>>> +    struct configfs_subsystem subsys;
>>>>> +#endif
>>>>>        /*
>>>>>         * This field is to keep a reference to "scsi_device"
>>>>> corresponding to
>>>>>         * "UFS device" W-LU.
>>>>> @@ -868,6 +872,19 @@ int ufshcd_read_string_desc(struct ufs_hba *hba, int
>>>>> desc_index,
>>>>>    int ufshcd_hold(struct ufs_hba *hba, bool async);
>>>>>    void ufshcd_release(struct ufs_hba *hba);
>>>>>    +/* Expose UFS configfs API's */
>>>>> +#ifndef CONFIG_UFS_PROVISION
>>>>> +static inline void ufshcd_configfs_init(struct ufs_hba *hba, const char
>>>>> *name)
>>>>> +{
>>>>> +}
>>>>> +static inline void ufshcd_configfs_exit(void)
>>>>> +{
>>>>> +}
>>>>> +#else
>>>>> +void ufshcd_configfs_init(struct ufs_hba *hba, const char *name);
>>>>> +void ufshcd_configfs_exit(void);
>>>>> +#endif
>>>>> +
>>>>>    int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn
>>>>> desc_id,
>>>>>        int *desc_length);
>>>>>   
>>>
> 
>