RE: [PATCH 4/7] scsi: ufs: add dme configuration primitives

[Seungwon Jeon <tgih.jun@samsung.com>]

On Mon, July 29, 2013, Subhash Jadavani wrote:
> On 7/26/2013 7:17 PM, Seungwon Jeon wrote:
> > Implements to support GET and SET operations of the DME.
> > These operations are used to configure the behavior of
> > the UNIPRO. Along with basic operation, {Peer/AttrSetType}
> > can be mixed.
> >
> > Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> > ---
> >   drivers/scsi/ufs/ufshcd.c |   88 +++++++++++++++++++++++++++++++++++++++++++++
> >   drivers/scsi/ufs/ufshcd.h |   51 ++++++++++++++++++++++++++
> >   drivers/scsi/ufs/ufshci.h |    6 +++
> >   3 files changed, 145 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 7152ec4..8277c40 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -188,6 +188,18 @@ static inline int ufshcd_get_uic_cmd_result(struct ufs_hba *hba)
> >   }
> >
> >   /**
> > + * ufshcd_get_dme_attr_val - Get the value of attribute returned by UIC command
> > + * @hba: Pointer to adapter instance
> > + *
> > + * This function gets UIC command argument3
> > + * Returns 0 on success, non zero value on error
> > + */
> > +static inline u32 ufshcd_get_dme_attr_val(struct ufs_hba *hba)
> > +{
> > +	return ufshcd_readl(hba, REG_UIC_COMMAND_ARG_3);
> > +}
> > +
> > +/**
> >    * ufshcd_is_valid_req_rsp - checks if controller TR response is valid
> >    * @ucd_rsp_ptr: pointer to response UPIU
> >    *
> > @@ -821,6 +833,80 @@ static int ufshcd_dme_link_startup(struct ufs_hba *hba)
> >   }
> >
> >   /**
> > + * ufshcd_dme_set_attr - UIC command for DME_SET, DME_PEER_SET
> > + * @hba: per adapter instance
> > + * @attr_sel: uic command argument1
> > + * @attr_set: attribute set type as uic command argument2
> > + * @mib_val: setting value as uic command argument3
> > + * @peer: indicate wherter peer or non-peer
> 
> typo: s/wtherter/whether
> This would sound better: s/non-peer/local
Ok.

> 
> Do above for ufshcd_dme_get_attr() function as well.
> > + *
> > + * Returns 0 on success, non-zero value on failure
> > + */
> > +int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
> > +			u8 attr_set, u32 mib_val, u8 peer)
> > +{
> > +	struct uic_command uic_cmd = {0};
> > +	static const char *const action[] = {
> > +		"dme-set",
> > +		"dme-peer-set"
> > +	};
> > +	const char *set = action[!!peer];
> > +	int ret;
> > +
> > +	uic_cmd.command = peer ?
> > +		UIC_CMD_DME_PEER_SET : UIC_CMD_DME_SET;
> > +	uic_cmd.argument1 = attr_sel;
> > +	uic_cmd.argument2 = UIC_ARG_ATTR_TYPE(attr_set);
> > +	uic_cmd.argument3 = mib_val;
> > +
> > +	ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> > +	if (ret)
> > +		dev_err(hba->dev, "%s: attr-id 0x%x error code %d\n",
> > +			set, UIC_GET_ATTR_ID(attr_sel), ret);
> 
> Its also good to print the "mib_val" which we were trying to set. It
> might be possible that DME_SET failed because we are trying to set out
> of range value to MIB attribute.
I'll add it.

> 
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(ufshcd_dme_set_attr);
> > +
> > +/**
> > + * ufshcd_dme_get_attr - UIC command for DME_GET, DME_PEER_GET
> > + * @hba: per adapter instance
> > + * @attr_sel: uic command argument1
> > + * @mib_val: the value of the attribute as returned by the UIC command
> > + * @peer: indicate wherter peer or non-peer
> > + *
> > + * Returns 0 on success, non-zero value on failure
> > + */
> > +int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
> > +			u32 *mib_val, u8 peer)
> > +{
> > +	struct uic_command uic_cmd = {0};
> > +	static const char *const action[] = {
> > +		"dme-get",
> > +		"dme-peer-get"
> > +	};
> > +	const char *get = action[!!peer];
> > +	int ret;
> > +
> > +	uic_cmd.command = peer ?
> > +		UIC_CMD_DME_PEER_GET : UIC_CMD_DME_GET;
> > +	uic_cmd.argument1 = attr_sel;
> > +
> > +	ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> > +	if (ret) {
> > +		dev_err(hba->dev, "%s: attr-id 0x%x error code %d\n",
> > +			get, UIC_GET_ATTR_ID(attr_sel), ret);
> > +		goto out;
> > +	}
> > +
> > +	if (mib_val)
> > +		*mib_val = uic_cmd.argument3;
> > +out:
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(ufshcd_dme_get_attr);
> > +
> > +/**
> >    * ufshcd_make_hba_operational - Make UFS controller operational
> >    * @hba: per adapter instance
> >    *
> > @@ -1256,6 +1342,8 @@ static void ufshcd_uic_cmd_compl(struct ufs_hba *hba)
> >   	if (hba->active_uic_cmd) {
> >   		hba->active_uic_cmd->argument2 |=
> >   			ufshcd_get_uic_cmd_result(hba);
> > +		hba->active_uic_cmd->argument3 =
> > +			ufshcd_get_dme_attr_val(hba);
> 
> We can optimize here by reading the dme_attribute value only if
> active_uic_cmd->command is set to DME_GET or DME_PEER_GET. For all other
> DME commands, meaning of this is "reserved" for read.
Right, you have a point.
But when considering the access of 'hba->active_uic_cmd->command" every time and additional 'branch statement',
it looks like no difference in terms of the optimization.
Reading the dme_attribute value could be trivial thing.

> Also, i guess reading of the argument2 and argument3 registers can be
> moved to ufshcd_wait_for_uic_cmd() function (process context) intead of
> interrupt context.
Yes, it may be possible.
But I wanted to update the result of uic command as soon as IS.UCCS occurs and simplify error handling.

Thanks,
Seungwon Jeon

> 
> >   		complete(&hba->active_uic_cmd->done);
> >   	}
> >   }
> > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
> > index 49590ee..50bcd29 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -199,6 +199,11 @@ int ufshcd_init(struct device *, struct ufs_hba ** , void __iomem * ,
> >   			unsigned int);
> >   void ufshcd_remove(struct ufs_hba *);
> >
> > +extern int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
> > +			       u8 attr_set, u32 mib_val, u8 peer);
> > +extern int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
> > +			       u32 *mib_val, u8 peer);
> > +
> >   /**
> >    * ufshcd_hba_stop - Send controller to reset state
> >    * @hba: per adapter instance
> > @@ -208,4 +213,50 @@ static inline void ufshcd_hba_stop(struct ufs_hba *hba)
> >   	ufshcd_writel(hba, CONTROLLER_DISABLE,  REG_CONTROLLER_ENABLE);
> >   }
> >
> > +/* UIC command interfaces for DME primitives */
> > +#define DME_LOCAL	0
> > +#define DME_PEER	1
> > +#define ATTR_SET_NOR	0	/* NORMAL */
> > +#define ATTR_SET_ST	1	/* STATIC */
> > +
> > +static inline int ufshcd_dme_set(struct ufs_hba *hba, u32 attr_sel,
> > +				 u32 mib_val)
> > +{
> > +	return ufshcd_dme_set_attr(hba, attr_sel, ATTR_SET_NOR,
> > +				   mib_val, DME_LOCAL);
> > +}
> > +
> > +static inline int ufshcd_dme_st_set(struct ufs_hba *hba, u32 attr_sel,
> > +				    u32 mib_val)
> > +{
> > +	return ufshcd_dme_set_attr(hba, attr_sel, ATTR_SET_ST,
> > +				   mib_val, DME_LOCAL);
> > +}
> > +
> > +static inline int ufshcd_dme_peer_set(struct ufs_hba *hba, u32 attr_sel,
> > +				      u32 mib_val)
> > +{
> > +	return ufshcd_dme_set_attr(hba, attr_sel, ATTR_SET_NOR,
> > +				   mib_val, DME_PEER);
> > +}
> > +
> > +static inline int ufshcd_dme_peer_st_set(struct ufs_hba *hba, u32 attr_sel,
> > +					 u32 mib_val)
> > +{
> > +	return ufshcd_dme_set_attr(hba, attr_sel, ATTR_SET_ST,
> > +				   mib_val, DME_PEER);
> > +}
> > +
> > +static inline int ufshcd_dme_get(struct ufs_hba *hba,
> > +				 u32 attr_sel, u32 *mib_val)
> > +{
> > +	return ufshcd_dme_get_attr(hba, attr_sel, mib_val, DME_LOCAL);
> > +}
> > +
> > +static inline int ufshcd_dme_peer_get(struct ufs_hba *hba,
> > +				      u32 attr_sel, u32 *mib_val)
> > +{
> > +	return ufshcd_dme_get_attr(hba, attr_sel, mib_val, DME_PEER);
> > +}
> > +
> >   #endif /* End of Header */
> > diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h
> > index a8f69cc..df4901e 100644
> > --- a/drivers/scsi/ufs/ufshci.h
> > +++ b/drivers/scsi/ufs/ufshci.h
> > @@ -191,6 +191,12 @@ enum {
> >   #define CONFIG_RESULT_CODE_MASK		0xFF
> >   #define GENERIC_ERROR_CODE_MASK		0xFF
> >
> > +#define UIC_ARG_MIB_SEL(attr, sel)	((((attr) & 0xFFFF) << 16) |\
> > +					 ((sel) & 0xFFFF))
> > +#define UIC_ARG_MIB(attr)		UIC_ARG_MIB_SEL(attr, 0)
> > +#define UIC_ARG_ATTR_TYPE(t)		(((t) & 0xFF) << 16)
> > +#define UIC_GET_ATTR_ID(v)		(((v) >> 16) & 0xFFFF)
> > +
> >   /* UIC Commands */
> >   enum {
> >   	UIC_CMD_DME_GET			= 0x01,
> 
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