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Subject: Re: [PATCH v3 22/27] powerpc/powernv/pmem: Implement the heartbeat
 command
To:     "Alastair D'Silva" <alastair@au1.ibm.com>, alastair@d-silva.org
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>,
        Andrew Donnellan <ajd@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>,
        =?UTF-8?Q?C=c3=a9dric_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
References: <20200221032720.33893-1-alastair@au1.ibm.com>
 <20200221032720.33893-23-alastair@au1.ibm.com>
From:   Frederic Barrat <fbarrat@linux.ibm.com>
Date:   Wed, 4 Mar 2020 15:25:57 +0100
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Le 21/02/2020 à 04:27, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> The heartbeat admin command is a simple admin command that exercises
> the communication mechanisms within the controller.
> 
> This patch issues a heartbeat command to the card during init to ensure
> we can communicate with the card's controller.
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---


Nothing to add compared to what has already been commented on previous 
patches (rc not set in probe(), higher level function to execute admin 
command in one call).

   Fred


>   arch/powerpc/platforms/powernv/pmem/ocxl.c | 43 ++++++++++++++++++++++
>   1 file changed, 43 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> index 081883a8247a..e01f6f9fc180 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> @@ -306,6 +306,44 @@ static bool is_usable(const struct ocxlpmem *ocxlpmem, bool verbose)
>   	return true;
>   }
>   
> +/**
> + * heartbeat() - Issue a heartbeat command to the controller
> + * @ocxlpmem: the device metadata
> + * Return: 0 if the controller responded correctly, negative on error
> + */
> +static int heartbeat(struct ocxlpmem *ocxlpmem)
> +{
> +	int rc;
> +
> +	mutex_lock(&ocxlpmem->admin_command.lock);
> +
> +	rc = admin_command_request(ocxlpmem, ADMIN_COMMAND_HEARTBEAT);
> +	if (rc)
> +		goto out;
> +
> +	rc = admin_command_execute(ocxlpmem);
> +	if (rc)
> +		goto out;
> +
> +	rc = admin_command_complete_timeout(ocxlpmem, ADMIN_COMMAND_HEARTBEAT);
> +	if (rc < 0) {
> +		dev_err(&ocxlpmem->dev, "Heartbeat timeout\n");
> +		goto out;
> +	}
> +
> +	rc = admin_response(ocxlpmem);
> +	if (rc < 0)
> +		goto out;
> +	if (rc != STATUS_SUCCESS)
> +		warn_status(ocxlpmem, "Unexpected status from heartbeat", rc);
> +
> +	(void)admin_response_handled(ocxlpmem);
> +
> +out:
> +	mutex_unlock(&ocxlpmem->admin_command.lock);
> +	return rc;
> +}
> +
>   /**
>    * allocate_minor() - Allocate a minor number to use for an OpenCAPI pmem device
>    * @ocxlpmem: the device metadata
> @@ -1458,6 +1496,11 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>   		goto err;
>   	}
>   
> +	if (heartbeat(ocxlpmem)) {
> +		dev_err(&pdev->dev, "Heartbeat failed\n");
> +		goto err;
> +	}
> +
>   	elapsed = 0;
>   	timeout = ocxlpmem->readiness_timeout + ocxlpmem->memory_available_timeout;
>   	while (!is_usable(ocxlpmem, false)) {
>