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

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Date:   Tue, 29 Oct 2019 12:49:11 +1100
From:   Andrew Donnellan <ajd@...ux.ibm.com>
To:     "Alastair D'Silva" <alastair@....ibm.com>, alastair@...ilva.org
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Frederic Barrat <fbarrat@...ux.ibm.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Keith Busch <keith.busch@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Anton Blanchard <anton@...abs.org>,
        Allison Randal <allison@...utok.net>,
        Cédric Le Goater <clg@...d.org>,
        David Gibson <david@...son.dropbear.id.au>,
        Vasant Hegde <hegdevasant@...ux.vnet.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Anju T Sudhakar <anju@...ux.vnet.ibm.com>,
        Hari Bathini <hbathini@...ux.ibm.com>,
        Mahesh Salgaonkar <mahesh@...ux.vnet.ibm.com>,
        Greg Kurz <groug@...d.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Alexey Kardashevskiy <aik@...abs.ru>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Oscar Salvador <osalvador@...e.com>,
        Michal Hocko <mhocko@...e.com>,
        Pavel Tatashin <pasha.tatashin@...een.com>,
        Wei Yang <richard.weiyang@...il.com>, Qian Cai <cai@....pw>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        linux-nvdimm@...ts.01.org, linux-mm@...ck.org
Subject: Re: [PATCH 04/10] powerpc: Map & release OpenCAPI LPC memory

On 25/10/19 3:46 pm, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@...ilva.org>
> 
> This patch adds platform support to map & release LPC memory.
>  > Signed-off-by: Alastair D'Silva <alastair@...ilva.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)

> +	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

> +
> +	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.

> +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.

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

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

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd@...ux.ibm.com             IBM Australia Limited