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Subject: Re: [PATCH v3 15/27] powerpc/powernv/pmem: Add support for near
 storage commands
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>
 <20200221032720.33893-16-alastair@au1.ibm.com>
From:   Frederic Barrat <fbarrat@linux.ibm.com>
Date:   Mon, 2 Mar 2020 18:58:40 +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>
> 
> Similar to the previous patch, this adds support for near storage commands.
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---


Is any of these new functions ever called?

   Fred


>   arch/powerpc/platforms/powernv/pmem/ocxl.c    |  6 +++
>   .../platforms/powernv/pmem/ocxl_internal.c    | 41 +++++++++++++++++++
>   .../platforms/powernv/pmem/ocxl_internal.h    | 37 +++++++++++++++++
>   3 files changed, 84 insertions(+)
> 
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> index 4e782d22605b..b8bd7e703b19 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
> @@ -259,12 +259,18 @@ static int setup_command_metadata(struct ocxlpmem *ocxlpmem)
>   	int rc;
>   
>   	mutex_init(&ocxlpmem->admin_command.lock);
> +	mutex_init(&ocxlpmem->ns_command.lock);
>   
>   	rc = extract_command_metadata(ocxlpmem, GLOBAL_MMIO_ACMA_CREQO,
>   				      &ocxlpmem->admin_command);
>   	if (rc)
>   		return rc;
>   
> +	rc = extract_command_metadata(ocxlpmem, GLOBAL_MMIO_NSCMA_CREQO,
> +					  &ocxlpmem->ns_command);
> +	if (rc)
> +		return rc;
> +
>   	return 0;
>   }
>   
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> index 583f48023025..3e0b133feddf 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.c
> @@ -133,6 +133,47 @@ int admin_response_handled(const struct ocxlpmem *ocxlpmem)
>   				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_CHI_ACRA);
>   }
>   
> +int ns_command_request(struct ocxlpmem *ocxlpmem, u8 op_code)
> +{
> +	u64 val;
> +	int rc = ocxl_global_mmio_read64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHI,
> +					 OCXL_LITTLE_ENDIAN, &val);
> +	if (rc)
> +		return rc;
> +
> +	if (!(val & GLOBAL_MMIO_CHI_NSCRA))
> +		return -EBUSY;
> +
> +	return scm_command_request(ocxlpmem, &ocxlpmem->ns_command, op_code);
> +}
> +
> +int ns_response(const struct ocxlpmem *ocxlpmem)
> +{
> +	return command_response(ocxlpmem, &ocxlpmem->ns_command);
> +}
> +
> +int ns_command_execute(const struct ocxlpmem *ocxlpmem)
> +{
> +	return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_HCI,
> +				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_HCI_NSCRW);
> +}
> +
> +bool ns_command_complete(const struct ocxlpmem *ocxlpmem)
> +{
> +	u64 val = 0;
> +	int rc = ocxlpmem_chi(ocxlpmem, &val);
> +
> +	WARN_ON(rc);
> +
> +	return (val & GLOBAL_MMIO_CHI_NSCRA) != 0;
> +}
> +
> +int ns_response_handled(const struct ocxlpmem *ocxlpmem)
> +{
> +	return ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIC,
> +				      OCXL_LITTLE_ENDIAN, GLOBAL_MMIO_CHI_NSCRA);
> +}
> +
>   void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
>   		     u8 status)
>   {
> diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> index 2fef68c71271..28e2020f6355 100644
> --- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> +++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
> @@ -107,6 +107,7 @@ struct ocxlpmem {
>   	struct ocxl_context *ocxl_context;
>   	void *metadata_addr;
>   	struct command_metadata admin_command;
> +	struct command_metadata ns_command;
>   	struct resource pmem_res;
>   	struct nd_region *nd_region;
>   	char fw_version[8+1];
> @@ -175,6 +176,42 @@ int admin_command_complete_timeout(const struct ocxlpmem *ocxlpmem,
>    */
>   int admin_response_handled(const struct ocxlpmem *ocxlpmem);
>   
> +/**
> + * ns_command_request() - Issue a near storage command request
> + * @ocxlpmem: the device metadata
> + * @op_code: The op-code for the command
> + * Returns an identifier for the command, or negative on error
> + */
> +int ns_command_request(struct ocxlpmem *ocxlpmem, u8 op_code);
> +
> +/**
> + * ns_response() - Validate a near storage response
> + * @ocxlpmem: the device metadata
> + * Returns the status code of the command, or negative on error
> + */
> +int ns_response(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * ns_command_execute() - Notify the controller to start processing a pending near storage command
> + * @ocxlpmem: the device metadata
> + * Returns 0 on success, negative on error
> + */
> +int ns_command_execute(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * ns_command_complete() - Is a near storage command executing
> + * @ocxlpmem: the device metadata
> + * Returns true if the previous admin command has completed
> + */
> +bool ns_command_complete(const struct ocxlpmem *ocxlpmem);
> +
> +/**
> + * ns_response_handled() - Notify the controller that the near storage response has been handled
> + * @ocxlpmem: the device metadata
> + * Returns 0 on success, negative on failure
> + */
> +int ns_response_handled(const struct ocxlpmem *ocxlpmem);
> +
>   /**
>    * warn_status() - Emit a kernel warning showing a command status.
>    * @ocxlpmem: the device metadata
>