Date:   Tue, 28 Aug 2018 17:10:00 +0530
From:   Sayali Lokhande <sayalil@...eaurora.org>
To:     Adrian Hunter <adrian.hunter@...el.com>, subhashj@...eaurora.org,
        cang@...eaurora.org, vivek.gautam@...eaurora.org,
        rnayak@...eaurora.org, vinholikatti@...il.com,
        jejb@...ux.vnet.ibm.com, martin.petersen@...cle.com,
        asutoshd@...eaurora.org, evgreen@...omium.org,
        riteshh@...eaurora.org
Cc:     linux-scsi@...r.kernel.org,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V10 2/2] scsi: ufs: Add configfs support for UFS
 provisioning


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@...eaurora.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 ?
>
>>>> +    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);
>>>>   
>>

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