linux-kernel - RE: [PATCH 03/11] soc/fsl: Introduce the DPAA BMan portal driver

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Message-ID: <BN3PR0301MB1267A318EF9DB3C193DA9FA08C9F0@BN3PR0301MB1267.namprd03.prod.outlook.com>
Date:	Fri, 10 Jul 2015 15:19:11 +0000
From:	Roy Pledge <roy.pledge@...escale.com>
To:	Paul Bolle <pebolle@...cali.nl>
CC:	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	"Scott Wood" <scottwood@...escale.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 03/11] soc/fsl: Introduce the DPAA BMan portal driver

Paul,

Thanks you for your valuable feedback so far.  Let me try to address a general issue you mention below: unused exported APIs.

The QMan and BMan drivers provide a base layer for other blocks built on top of them, for instance an Ethernet Driver, an Encrypt/Decrypt Engine,  a pattern matcher, a compress/decompress engine, etc...
Some of these drivers will be presented for review in the near future, but in order to try and layer the review/up streaming process we're presenting each layer as independently as possible.
If you really were to start dissecting which APIs are called you would come to a very small set of pieces that merely initialize the hardware but don't provide any opportunity for other users to invoke that HW. 

I hope that this helps you understand our goals in trying to upstream these drivers.


Roy

> -----Original Message-----
> From: Paul Bolle [mailto:pebolle@...cali.nl]
> Sent: Friday, July 10, 2015 9:33 AM
> To: Pledge Roy-R01356
> Cc: linuxppc-dev@...ts.ozlabs.org; Wood Scott-B07421;
> netdev@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 03/11] soc/fsl: Introduce the DPAA BMan portal driver
> 
> On do, 2015-07-09 at 16:21 -0400, Roy Pledge wrote:
> > --- a/drivers/soc/fsl/qbman/Kconfig
> > +++ b/drivers/soc/fsl/qbman/Kconfig
> 
> > +config FSL_DPA_PIRQ_FAST
> > +	bool
> > +	default y
> 
> First used in 04/11.
> 
> > +config FSL_DPA_PIRQ_SLOW
> > +	bool
> > +	default y
> > +
> > +config FSL_DPA_PORTAL_SHARE
> > +	bool
> > +	default y
> 
> As in 02/11: these three symbols function as aliases for FSL_DPA. Why are
> they needed?
> 
> >  config FSL_BMAN
> >  	tristate "BMan device management"
> >  	default n
> >  	help
> >  		FSL DPAA BMan driver
> >
> > +config FSL_BMAN_PORTAL
> > +	tristate "BMan portal(s)"
> > +	default n
> > +	help
> > +		FSL BMan portal driver
> 
> > --- /dev/null
> > +++ b/drivers/soc/fsl/qbman/bman_api.c
> 
> > +struct bman_portal {
> > +	[...]
> > +#ifdef CONFIG_FSL_DPA_CAN_WAIT_SYNC
> 
> This check will always evaluate to true, right? (I'll only report this
> once.)
> 
> > +	struct bman_pool *rcri_owned; /* only 1 release WAIT_SYNC at
> > a time */
> > +#endif
> > +#ifdef CONFIG_FSL_DPA_PORTAL_SHARE
> 
> Ditto.
> 
> > +	raw_spinlock_t sharing_lock; /* only used if is_shared */
> > +	int is_shared;
> > +	struct bman_portal *sharing_redirect; #endif
> > +	[...]
> > +};
> 
> > +const struct bman_portal_config *bman_get_portal_config(void) {
> > +	[...]
> > +}
> 
> I couldn't find callers of this function.
> 
> > +EXPORT_SYMBOL(bman_get_portal_config);
> 
> Nor users of this export, obviously.
> 
> > +
> > +u32 bman_irqsource_get(void)
> > +{
> > +	[...]
> > +}
> 
> Ditto.
> 
> > +EXPORT_SYMBOL(bman_irqsource_get);
> 
> Ditto.
> 
> > +int bman_p_irqsource_add(struct bman_portal *p, __maybe_unused u32
> > +bits) {
> > +	[...]
> > +}
> > +EXPORT_SYMBOL(bman_p_irqsource_add);
> 
> There seem to be no users of this export.
> 
> > +int bman_irqsource_add(__maybe_unused u32 bits) {
> > +	[...]
> > +}
> 
> Unused.
> 
> > +EXPORT_SYMBOL(bman_irqsource_add);
> 
> Ditto.
> 
> > +int bman_irqsource_remove(u32 bits)
> > +{
> > +	[...]
> > +}
> 
> Ditto.
> 
> > +EXPORT_SYMBOL(bman_irqsource_remove);
> 
> Ditto.
> 
> > +u32 bman_poll_slow(void)
> > +{
> > +	[...]
> > +}
> 
> Ditto.
> 
> > +EXPORT_SYMBOL(bman_poll_slow);
> 
> Ditto.
> 
> > +void bman_poll(void)
> > +{
> > +	[...]
> > +}
> 
> Ditto.
> 
> > +EXPORT_SYMBOL(bman_poll);
> 
> Ditto.
> 
> > +static inline struct bm_rcr_entry *try_rel_start(struct bman_portal
> > +**p, #ifdef CONFIG_FSL_DPA_CAN_WAIT
> 
> Always true, right?
> 
> > +					__maybe_unused struct bman_pool
> *pool, #endif
> > +					__maybe_unused unsigned long
> *irqflags,
> > +					__maybe_unused u32 flags)
> 
> And this is a, well, novel way to declare a function.
> 
> > +{
> > +	[...]
> > +}
> 
> > +int bman_flush_stockpile(struct bman_pool *pool, u32 flags) {
> > +	[...]
> > +}
> 
> Unused function.
> 
> > +EXPORT_SYMBOL(bman_flush_stockpile);
> 
> So unused export too.
> 
> > +#ifdef CONFIG_FSL_BMAN
> > +u32 bman_query_free_buffers(struct bman_pool *pool) {
> > +	return bm_pool_free_buffers(pool->params.bpid);
> > +}
> > +EXPORT_SYMBOL(bman_query_free_buffers);
> > +
> > +int bman_update_pool_thresholds(struct bman_pool *pool, const u32
> > +*thresholds) {
> > +	u32 bpid;
> > +
> > +	bpid = bman_get_params(pool)->bpid;
> > +
> > +	return bm_pool_set(bpid, thresholds); }
> > +EXPORT_SYMBOL(bman_update_pool_thresholds);
> 
> More of the same.
> 
> > +#endif
> 
> > --- /dev/null
> > +++ b/drivers/soc/fsl/qbman/bman_portal.c
> >
> > +module_driver(bman_portal_driver,
> > +	       bman_portal_driver_register, platform_driver_unregister);
> 
> No MODULE_LICENSE() here, nor in the other files that make up this module.
> So loading this module will trigger a warning and taint the kernel.
> 
> > --- /dev/null
> > +++ b/drivers/soc/fsl/qbman/bman_utils.c
> 
> > +EXPORT_SYMBOL(bman_alloc_bpid_range);
> 
> Unused export.
> 
> > +EXPORT_SYMBOL(bman_release_bpid_range);
> 
> Ditto.
> 
> > +EXPORT_SYMBOL(bman_seed_bpid_range);
> 
> Ditto.
> 
> > +int bman_reserve_bpid_range(u32 bpid, u32 count) {
> > +	return dpaa_resource_reserve(&bpalloc, bpid, count); }
> > +EXPORT_SYMBOL(bman_reserve_bpid_range);
> 
> Because bman_reserve_bpid() is unused, see below, this function and this
> export are unused too.
> 
> > --- /dev/null
> > +++ b/drivers/soc/fsl/qbman/dpaa_resource.c
> >
> > +#if defined(CONFIG_FSL_BMAN_PORTAL) ||
> > +defined(CONFIG_FSL_BMAN_PORTAL_MODULE)
> 
> #if IS_ENABLED(CONFIG_FSL_BMAN_PORTAL)
> 
> > +#ifdef DPAA_RESOURCE_DEBUG
> 
> Never defined. So DUMP() is dead code.
> 
> > --- a/drivers/soc/fsl/qbman/dpaa_sys.h
> > +++ b/drivers/soc/fsl/qbman/dpaa_sys.h
> >
> > +#define CONFIG_TRY_BETTER_MEMCPY
> 
> Please replace the CONFIG_ prefix with something else.
> 
> > +#ifdef CONFIG_TRY_BETTER_MEMCPY
> 
> This will always be true, right?
> 
> > [...]
> > +#else
> > +#define copy_words memcpy
> > +#define copy_shorts memcpy
> > +#define copy_bytes memcpy
> > +#endif
> 
> > --- /dev/null
> > +++ b/include/soc/fsl/bman.h
> 
> > +static inline int bman_reserve_bpid(u32 bpid) {
> > +	return bman_reserve_bpid_range(bpid, 1); }
> 
> Unused.
> 
> Thanks,
> 
> 
> Paul Bolle