Re: [PATCH 04/10] powerpc: Map & release OpenCAPI LPC memory

From: "Alastair D'Silva" <alastair@au1.ibm.com>
To: Andrew Donnellan <ajd@linux.ibm.com>
Cc: "Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Paul Mackerras" <paulus@samba.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Frederic Barrat" <fbarrat@linux.ibm.com>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Geert Uytterhoeven" <geert+renesas@glider.be>,
	"Krzysztof Kozlowski" <krzk@kernel.org>,
	"Anton Blanchard" <anton@ozlabs.org>,
	"Allison Randal" <allison@lohutok.net>,
	"Cédric Le Goater" <clg@kaod.org>,
	"David Gibson" <david@gibson.dropbear.id.au>,
	"Vasant Hegde" <hegdevasant@linux.vnet.ibm.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Anju T Sudhakar" <anju@linux.vnet.ibm.com>,
	"Hari Bathini" <hbathini@linux.ibm.com>,
	"Mahesh Salgaonkar" <mahesh@linux.vnet.ibm.com>,
	"Greg Kurz" <groug@kaod.org>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Alexey Kardashevskiy" <aik@ozlabs.ru>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"David Hildenbrand" <david@redhat.com>,
	"Oscar Salvador" <osalvador@suse.com>,
	"Michal Hocko" <mhocko@suse.com>,
	"Pavel Tatashin" <pasha.tatashin@soleen.com>,
	"Wei Yang" <richard.weiyang@gmail.com>, "Qian Cai" <cai@lca.pw>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-mm@kvack.org
Subject: Re: [PATCH 04/10] powerpc: Map & release OpenCAPI LPC memory
Date: Tue, 29 Oct 2019 13:44:19 +1100	[thread overview]
Message-ID: <4dc37533df4f5566fdbe5c212289c438d0fe2c3b.camel@au1.ibm.com> (raw)
In-Reply-To: <32caa2ef-43b2-f71d-f470-ccfed0ae094e@linux.ibm.com>

On Tue, 2019-10-29 at 12:49 +1100, Andrew Donnellan wrote:
> On 25/10/19 3:46 pm, Alastair D'Silva wrote:
> > From: Alastair D'Silva <alastair@d-silva.org>
> > 
> > This patch adds platform support to map & release LPC memory.
> >  > Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> > ---
> >   arch/powerpc/include/asm/pnv-ocxl.h   |  2 ++
> >   arch/powerpc/platforms/powernv/ocxl.c | 41
> > +++++++++++++++++++++++++++
> >   include/linux/memory_hotplug.h        |  5 ++++
> >   mm/memory_hotplug.c                   |  3 +-
> >   4 files changed, 50 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/powerpc/include/asm/pnv-ocxl.h
> > b/arch/powerpc/include/asm/pnv-ocxl.h
> > index 7de82647e761..f8f8ffb48aa8 100644
> > --- a/arch/powerpc/include/asm/pnv-ocxl.h
> > +++ b/arch/powerpc/include/asm/pnv-ocxl.h
> > @@ -32,5 +32,7 @@ extern int pnv_ocxl_spa_remove_pe_from_cache(void
> > *platform_data, int pe_handle)
> >   
> >   extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
> >   extern void pnv_ocxl_free_xive_irq(u32 irq);
> > +extern u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64
> > size);
> > +extern void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev);
> >   
> >   #endif /* _ASM_PNV_OCXL_H */
> > diff --git a/arch/powerpc/platforms/powernv/ocxl.c
> > b/arch/powerpc/platforms/powernv/ocxl.c
> > index 8c65aacda9c8..c6d4234e0aba 100644
> > --- a/arch/powerpc/platforms/powernv/ocxl.c
> > +++ b/arch/powerpc/platforms/powernv/ocxl.c
> > @@ -475,6 +475,47 @@ void pnv_ocxl_spa_release(void *platform_data)
> >   }
> >   EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
> >   
> > +u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64 size)
> > +{
> > +	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
> > +	struct pnv_phb *phb = hose->private_data;
> > +	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
> 
> I think pci_dev_id() is the canonical way to do this? (same applies
> in 
> release)

Thanks.

> 
> > +	u64 base_addr = 0;
> > +	int rc;
> > +
> > +	rc = opal_npu_mem_alloc(phb->opal_id, bdfn, size, &base_addr);
> > +	if (rc) {
> > +		dev_warn(&pdev->dev,
> > +			 "OPAL could not allocate LPC memory, rc=%d\n",
> > rc);
> > +		return 0;
> > +	}
> > +
> > +	base_addr = be64_to_cpu(base_addr);
> 
> sparse doesn't like this, the way it's usually done is declare a
> __be64 
> variable, pass that to the opal call, then store the conversion in a 
> regular u64
> 

Ok.

> > +
> > +	rc = check_hotplug_memory_addressable(base_addr >> PAGE_SHIFT,
> > +					      size >> PAGE_SHIFT);
> > +	if (rc)
> > +		return 0;
> > +
> > +	return base_addr;
> > +}
> > +EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_setup);
> > +
> > +void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev)
> > +{
> > +	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
> > +	struct pnv_phb *phb = hose->private_data;
> > +	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
> > +	int rc;
> > +
> > +	rc = opal_npu_mem_release(phb->opal_id, bdfn);
> > +	if (rc)
> > +		dev_warn(&pdev->dev,
> > +			 "OPAL reported rc=%d when releasing LPC
> > memory\n", rc);
> > +}
> > +EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_release);
> > +
> > +
> >   int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int
> > pe_handle)
> >   {
> >   	struct spa_data *data = (struct spa_data *) platform_data;
> > diff --git a/include/linux/memory_hotplug.h
> > b/include/linux/memory_hotplug.h
> > index f46ea71b4ffd..3f5f1a642abe 100644
> > --- a/include/linux/memory_hotplug.h
> > +++ b/include/linux/memory_hotplug.h
> > @@ -339,6 +339,11 @@ static inline int remove_memory(int nid, u64
> > start, u64 size)
> >   static inline void __remove_memory(int nid, u64 start, u64 size)
> > {}
> >   #endif /* CONFIG_MEMORY_HOTREMOVE */
> >   
> > +#if CONFIG_MEMORY_HOTPLUG_SPARSE
> 
> This needs to be #ifdef.
> 

Yup, 0 day caught that one too :)

> > +int check_hotplug_memory_addressable(unsigned long pfn,
> > +		unsigned long nr_pages);
> > +#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
> > +
> >   extern void __ref free_area_init_core_hotplug(int nid);
> >   extern int __add_memory(int nid, u64 start, u64 size);
> >   extern int add_memory(int nid, u64 start, u64 size);
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index 2cecf07b396f..b39827dbd071 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -278,7 +278,7 @@ static int check_pfn_span(unsigned long pfn,
> > unsigned long nr_pages,
> >   	return 0;
> >   }
> >   
> > -static int check_hotplug_memory_addressable(unsigned long pfn,
> > +int check_hotplug_memory_addressable(unsigned long pfn,
> >   					    unsigned long nr_pages)
> >   {
> >   	const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1;
> > @@ -294,6 +294,7 @@ static int
> > check_hotplug_memory_addressable(unsigned long pfn,
> >   
> >   	return 0;
> >   }
> > +EXPORT_SYMBOL_GPL(check_hotplug_memory_addressable);
> 
> This export seems unnecessary, you don't seem to be using this
> function 
> in a module anywhere in this series AFAICT.
> 

This is used within this patch, in the map call.

> Also it looks like a whitespace fix from removing the static ended up
> in 
> patch #8 rather than here.

Thanks.

> 
> >   
> >   /*
> >    * Reasonably generic function for adding memory.  It is
> > 

-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819
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