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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>
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: <a8405e52-ab28-f7ad-e150-4a633d0ad4bc@intel.com>
Date:   Tue, 28 Aug 2018 14:26:15 +0300
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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.

> 
>>> +        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

>>> +    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);
>>>  
> 
>