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Subject: Re: [PATCH 4/5] ocxl: Add functions to map/unmap LPC memory
From:   "Alastair D'Silva" <alastair@au1.ibm.com>
To:     "Alastair D'Silva" <alastair@au1.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>,
        Andrew Donnellan <ajd@linux.ibm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        =?ISO-8859-1?Q?C=E9dric?= Le Goater <clg@kaod.org>,
        Allison Randal <allison@lohutok.net>,
        Vaibhav Jain <vaibhav@linux.ibm.com>,
        Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
        Anju T Sudhakar <anju@linux.vnet.ibm.com>,
        David Gibson <david@gibson.dropbear.id.au>,
        Nicholas Piggin <npiggin@gmail.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Date:   Thu, 19 Sep 2019 11:24:49 +1000
In-Reply-To: <20190917014307.30485-5-alastair@au1.ibm.com>
References: <20190917014307.30485-1-alastair@au1.ibm.com>
         <20190917014307.30485-5-alastair@au1.ibm.com>
Organization: IBM Australia
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On Tue, 2019-09-17 at 11:43 +1000, Alastair D'Silva wrote:
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> Add functions to map/unmap LPC memory
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>  drivers/misc/ocxl/config.c        |  4 +++
>  drivers/misc/ocxl/core.c          | 50
> +++++++++++++++++++++++++++++++
>  drivers/misc/ocxl/link.c          |  4 +--
>  drivers/misc/ocxl/ocxl_internal.h | 10 +++++--
>  include/misc/ocxl.h               | 18 +++++++++++
>  5 files changed, 82 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/config.c b/drivers/misc/ocxl/config.c
> index c8e19bfb5ef9..fb0c3b6f8312 100644
> --- a/drivers/misc/ocxl/config.c
> +++ b/drivers/misc/ocxl/config.c
> @@ -568,6 +568,10 @@ static int read_afu_lpc_memory_info(struct
> pci_dev *dev,
>  		afu->special_purpose_mem_size =
>  			total_mem_size - lpc_mem_size;
>  	}
> +
> +	dev_info(&dev->dev, "Probed LPC memory of %#llx bytes and
> special purpose memory of %#llx bytes\n",
> +		afu->lpc_mem_size, afu->special_purpose_mem_size);
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> index fdfe4e0a34e1..eb24bb9d655f 100644
> --- a/drivers/misc/ocxl/core.c
> +++ b/drivers/misc/ocxl/core.c
> @@ -210,6 +210,55 @@ static void unmap_mmio_areas(struct ocxl_afu
> *afu)
>  	release_fn_bar(afu->fn, afu->config.global_mmio_bar);
>  }
>  
> +int ocxl_map_lpc_mem(struct ocxl_afu *afu)
> +{
> +	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
> +
> +	if ((afu->config.lpc_mem_size + afu-
> >config.special_purpose_mem_size) == 0)
> +		return 0;
> +
> +	afu->lpc_base_addr = ocxl_link_lpc_online(afu->fn->link, dev);
> +	if (afu->lpc_base_addr == 0)
> +		return -EINVAL;
> +
> +	if (afu->config.lpc_mem_size) {
> +		afu->lpc_res.start = afu->lpc_base_addr + afu-
> >config.lpc_mem_offset;
> +		afu->lpc_res.end = afu->lpc_res.start + afu-
> >config.lpc_mem_size - 1;
> +	}
> +
> +	if (afu->config.special_purpose_mem_size) {
> +		afu->special_purpose_res.start = afu->lpc_base_addr +
> +						 afu-
> >config.special_purpose_mem_offset;
> +		afu->special_purpose_res.end = afu-
> >special_purpose_res.start +
> +					       afu-
> >config.special_purpose_mem_size - 1;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(ocxl_map_lpc_mem);
> +
> +struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu)
> +{
> +	return &afu->lpc_res;
> +}
> +EXPORT_SYMBOL(ocxl_afu_lpc_mem);
> +
> +static void unmap_lpc_mem(struct ocxl_afu *afu)
> +{
> +	struct pci_dev *dev = to_pci_dev(afu->fn->dev.parent);
> +
> +	if (afu->lpc_res.start || afu->special_purpose_res.start) {
> +		void *link = afu->fn->link;
> +
> +		ocxl_link_lpc_offline(link, dev);
> +
> +		afu->lpc_res.start = 0;
> +		afu->lpc_res.end = 0;
> +		afu->special_purpose_res.start = 0;
> +		afu->special_purpose_res.end = 0;
> +	}
> +}
> +
>  static int configure_afu(struct ocxl_afu *afu, u8 afu_idx, struct
> pci_dev *dev)
>  {
>  	int rc;
> @@ -250,6 +299,7 @@ static int configure_afu(struct ocxl_afu *afu, u8
> afu_idx, struct pci_dev *dev)
>  
>  static void deconfigure_afu(struct ocxl_afu *afu)
>  {
> +	unmap_lpc_mem(afu);
>  	unmap_mmio_areas(afu);
>  	reclaim_afu_pasid(afu);
>  	reclaim_afu_actag(afu);
> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> index 2874811a4398..9e303a5f4d85 100644
> --- a/drivers/misc/ocxl/link.c
> +++ b/drivers/misc/ocxl/link.c
> @@ -738,7 +738,7 @@ int ocxl_link_add_lpc_mem(void *link_handle, u64
> size)
>  }
>  EXPORT_SYMBOL_GPL(ocxl_link_add_lpc_mem);
>  
> -u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev)
> +u64 ocxl_link_lpc_online(void *link_handle, struct pci_dev *pdev)
>  {
>  	struct ocxl_link *link = (struct ocxl_link *) link_handle;
>  
> @@ -759,7 +759,7 @@ u64 ocxl_link_lpc_map(void *link_handle, struct
> pci_dev *pdev)
>  	return link->lpc_mem;
>  }
>  
> -void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev)
> +void ocxl_link_lpc_offline(void *link_handle, struct pci_dev *pdev)
>  {
>  	struct ocxl_link *link = (struct ocxl_link *) link_handle;
>  
> diff --git a/drivers/misc/ocxl/ocxl_internal.h
> b/drivers/misc/ocxl/ocxl_internal.h
> index db2647a90fc8..5656a4aab5b7 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -52,6 +52,12 @@ struct ocxl_afu {
>  	void __iomem *global_mmio_ptr;
>  	u64 pp_mmio_start;
>  	void *private;
> +	u64 lpc_base_addr; /* Covers both LPC & special purpose memory
> */
> +	struct bin_attribute attr_global_mmio;
> +	struct bin_attribute attr_lpc_mem;

The bin_attributes are not needed here.

> +	struct resource lpc_res;
> +	struct bin_attribute attr_special_purpose_mem;
> +	struct resource special_purpose_res;
>  };
>  
>  enum ocxl_context_status {
> @@ -170,7 +176,7 @@ extern u64 ocxl_link_get_lpc_mem_sz(void
> *link_handle);
>   * @link_handle: The OpenCAPI link handle
>   * @pdev: A device that is on the link
>   */
> -u64 ocxl_link_lpc_map(void *link_handle, struct pci_dev *pdev);
> +u64 ocxl_link_lpc_online(void *link_handle, struct pci_dev *pdev);
>  
>  /**
>   * Release the LPC memory device for an OpenCAPI device
> @@ -181,6 +187,6 @@ u64 ocxl_link_lpc_map(void *link_handle, struct
> pci_dev *pdev);
>   * @link_handle: The OpenCAPI link handle
>   * @pdev: A device that is on the link
>   */
> -void ocxl_link_lpc_release(void *link_handle, struct pci_dev *pdev);
> +void ocxl_link_lpc_offline(void *link_handle, struct pci_dev *pdev);
>  
>  #endif /* _OCXL_INTERNAL_H_ */
> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
> index 06dd5839e438..a1897737908d 100644
> --- a/include/misc/ocxl.h
> +++ b/include/misc/ocxl.h
> @@ -212,6 +212,24 @@ int ocxl_irq_set_handler(struct ocxl_context
> *ctx, int irq_id,
>  
>  // AFU Metadata
>  
> +/**
> + * Map the LPC system & special purpose memory for an AFU
> + *
> + * Do not call this during device discovery, as there may me
> multiple
> + * devices on a link, and the memory is mapped for the whole link,
> not
> + * just one device. It should only be called after all devices have
> + * registered their memory on the link.
> + *
> + * afu: The AFU that has the LPC memory to map
> + */
> +extern int ocxl_map_lpc_mem(struct ocxl_afu *afu);
> +
> +/**
> + * Get the physical address range of LPC memory for an AFU
> + * afu: The AFU associated with the LPC memory
> + */
> +extern struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu);
> +
>  /**
>   * Get a pointer to the config for an AFU
>   *
-- 
Alastair D'Silva
Open Source Developer
Linux Technology Centre, IBM Australia
mob: 0423 762 819