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Subject: Re: [PATCH v3 13/27] powerpc/powernv/pmem: Read the capability
 registers & wait for device ready
From:   "Alastair D'Silva" <alastair@au1.ibm.com>
To:     Andrew Donnellan <ajd@linux.ibm.com>
Cc:     "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        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>,
        Dan Williams <dan.j.williams@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Rob Herring <robh@kernel.org>,
        Anton Blanchard <anton@ozlabs.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
        Madhavan Srinivasan <maddy@linux.vnet.ibm.com>,
        =?ISO-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>,
        Anju T Sudhakar <anju@linux.vnet.ibm.com>,
        Hari Bathini <hbathini@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kurz <groug@kaod.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-nvdimm@lists.01.org, linux-mm@kvack.org
Date:   Thu, 27 Feb 2020 14:58:08 +1100
In-Reply-To: <c6ce554a-62b4-2675-9ec3-1ded8eaacfc4@linux.ibm.com>
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         <20200221032720.33893-14-alastair@au1.ibm.com>
         <c6ce554a-62b4-2675-9ec3-1ded8eaacfc4@linux.ibm.com>
Organization: IBM Australia
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On Thu, 2020-02-27 at 14:54 +1100, Andrew Donnellan wrote:
> On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> > +/**
> > + * read_device_metadata() - Retrieve config information from the
> > AFU and save it for future use
> > + * @ocxlpmem: the device metadata
> > + * Return: 0 on success, negative on failure
> > + */
> > +static int read_device_metadata(struct ocxlpmem *ocxlpmem)
> > +{
> > +	u64 val;
> > +	int rc;
> > +
> > +	rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu,
> > GLOBAL_MMIO_CCAP0,
> > +				     OCXL_LITTLE_ENDIAN, &val);
> > +	if (rc)
> > +		return rc;
> > +
> > +	ocxlpmem->scm_revision = val & 0xFFFF;
> > +	ocxlpmem->read_latency = (val >> 32) & 0xFF;
> 
> This field is 16 bits in the spec, so the mask should be 0xFFFF I
> think?
> 

You're right, I'll fix it.

> Maybe we should generalise the EXTRACT_BITS macro we use in ocxl :)
> 
-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819