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Subject: Re: [PATCH V8 2/2] scsi: ufs: Add configfs support for UFS
 provisioning
To:     Evan Green <evgreen@chromium.org>
Cc:     subhashj@codeaurora.org, cang@codeaurora.org,
        vivek.gautam@codeaurora.org,
        Rajendra Nayak <rnayak@codeaurora.org>,
        Vinayak Holikatti <vinholikatti@gmail.com>,
        jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
        asutoshd@codeaurora.org, riteshh@codeaurora.org,
        adrian.hunter@intel.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1533805799-5831-1-git-send-email-sayalil@codeaurora.org>
 <1533805799-5831-3-git-send-email-sayalil@codeaurora.org>
 <CAE=gft6RFCe5cfOZkwMpaKD71yiL1m1oActbax3Hx8+jXDPvVQ@mail.gmail.com>
From:   Sayali Lokhande <sayalil@codeaurora.org>
Message-ID: <5ba7f263-0fa2-0ca8-7f76-989ec3fb7cc5@codeaurora.org>
Date:   Tue, 21 Aug 2018 15:19:06 +0530
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On 8/17/2018 11:47 PM, Evan Green wrote:
> On Thu, Aug 9, 2018 at 2:10 AM Sayali Lokhande <sayalil@codeaurora.org> 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               | 159 ++++++++++++++++++++++++++
>>   drivers/scsi/ufs/ufshcd.c                     |   7 +-
>>   drivers/scsi/ufs/ufshcd.h                     |  10 ++
>>   6 files changed, 204 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
>> +Date:          Jun 2018
>> +KernelVersion: 4.14
>> +Description:
>> +               This file shows the current ufs configuration descriptor set in device.
>> +               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:
>> +               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>
>> +               > /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..cd1a227
>> --- /dev/null
>> +++ b/drivers/scsi/ufs/ufs-configfs.c
>> @@ -0,0 +1,159 @@
>> +// 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};
>> +       int buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
>> +       int i, ret, curr_len = 0;
>> +       struct ufs_hba *hba = config_item_to_hba(item);
>> +
>> +       if (!hba)
>> +               return -EINVAL;
> I don't think this is actually possible. Is a configfs show function
> ever called with a null item?
Agree. In init , we get the valid hba pointer. So I can remove this 
check. Will update.
>> +
>> +       ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
>> +               QUERY_DESC_IDN_CONFIGURATION, 0, 0, desc_buf, &buff_len);
>> +
>> +       if (ret)
>> +               return ret;
>> +
>> +       for (i = 0; i < buff_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 buff_len = QUERY_DESC_CONFIGURATION_DEF_SIZE;
>> +       char *token;
>> +       int i, ret, value;
>> +       u32 bConfigDescrLock = 0;
> I haven't seen many examples of variables named this way. I know it
> follows what the UFS spec does, but I haven't noticed examples of
> people naming their locals outside of normal Linux conventions.
Done. Will update the naming.
>> +
>> +       /* reserve one byte for null termination */
>> +       strbuf = kmalloc(count + 1, GFP_KERNEL);
>> +       if (!strbuf)
>> +               return -ENOMEM;
>> +
>> +       strbuf_copy = strbuf;
>> +       strlcpy(strbuf, buf, count + 1);
>> +
>> +       if (!hba)
>> +               goto out;
> Again, is this possible?
Done. will remove this check.
>> +
>> +       /* 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, &bConfigDescrLock);
>> +       if (ret)
>> +               goto out;
>> +
>> +       if (bConfigDescrLock) {
>> +               dev_err(hba->dev, "%s: bConfigDescrLock already set to %u, cannot re-provision device!\n",
>> +               __func__, bConfigDescrLock);
>> +               goto out;
> You're succeeding here, shouldn't you fail the write? In fact, you
> succeed the write in a whole bunch of failure cases. Please fail the
> write in error cases.
Agree. Will set the err val in return and check for error/ret set and 
return accordingly.
>> +       }
>> +
>> +       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);
>> +                       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, &buff_len);
>> +
>> +       if (!ret)
>> +               dev_err(hba->dev, "%s: UFS Provisioning done, reboot now!\n",
>> +               __func__);
>> +
>> +out:
>> +       kfree(strbuf_copy);
>> +       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,
>> +               },
>> +       },
>> +};
>> +
>> +int 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;
>> +       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);
>> +
>> +       return ret;
>> +}
>> +
>> +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 0cbdde7..bc7bffc 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -7711,6 +7711,9 @@ int ufshcd_shutdown(struct ufs_hba *hba)
>>   void ufshcd_remove(struct ufs_hba *hba)
>>   {
>>          ufs_sysfs_remove_nodes(hba->dev);
>> +#ifdef CONFIG_UFS_PROVISION
>> +       ufshcd_configfs_exit();
>> +#endif
>>          scsi_remove_host(hba->host);
>>          /* disable interrupts */
>>          ufshcd_disable_intr(hba, hba->intr_mask);
>> @@ -7964,7 +7967,9 @@ 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);
>> -
>> +#ifdef CONFIG_UFS_PROVISION
>> +       ufshcd_configfs_init(hba, dev_name(hba->dev));
>> +#endif
> Normally the way I see this done is to define stub functions up in the
> header when !CONFIG_UFS_PROVISION, rather than ifdefs in the code. Can
> you do it that way?
Done. Will update.
>>          return 0;
>>
>>   out_remove_scsi_host:
>> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
>> index 101a75c..7b6cc88 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 +872,12 @@ 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 */
>> +#ifdef CONFIG_UFS_PROVISION
>> +extern int ufshcd_configfs_init(struct ufs_hba *hba, const char *name);
>> +extern 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);
>>
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>>