Re: [PATCH v4 07/25] ocxl: Add functions to map/unmap LPC memory

[Dan Williams]

On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@xxxxxxxxxxx> wrote:
>
> Add functions to map/unmap LPC memory
>

"map memory" is an overloaded term. I'm guessing this patch has
nothing to do with mapping memory in the MMU. Is it updating hardware
resource decoders to start claiming address space that was allocated
previously?

> Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
> Acked-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxx>
> ---
>  drivers/misc/ocxl/core.c          | 51 +++++++++++++++++++++++++++++++
>  drivers/misc/ocxl/ocxl_internal.h |  3 ++
>  include/misc/ocxl.h               | 21 +++++++++++++
>  3 files changed, 75 insertions(+)
>
> diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> index 2531c6cf19a0..75ff14e3882a 100644
> --- a/drivers/misc/ocxl/core.c
> +++ b/drivers/misc/ocxl/core.c
> @@ -210,6 +210,56 @@ static void unmap_mmio_areas(struct ocxl_afu *afu)
>         release_fn_bar(afu->fn, afu->config.global_mmio_bar);
>  }
>
> +int ocxl_afu_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_map(afu->fn->link, dev);
> +       if (afu->lpc_base_addr == 0)
> +               return -EINVAL;
> +
> +       if (afu->config.lpc_mem_size > 0) {
> +               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 > 0) {
> +               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_GPL(ocxl_afu_map_lpc_mem);
> +
> +struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu)
> +{
> +       return &afu->lpc_res;
> +}
> +EXPORT_SYMBOL_GPL(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;
> +
> +               // only release the link when the the last consumer calls release
> +               ocxl_link_lpc_release(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;
> @@ -251,6 +301,7 @@ 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/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
> index 2d7575225bd7..7b975a89db7b 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -52,6 +52,9 @@ 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 resource lpc_res;
> +       struct resource special_purpose_res;
>  };
>
>  enum ocxl_context_status {
> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
> index 357ef1aadbc0..d8b0b4d46bfb 100644
> --- a/include/misc/ocxl.h
> +++ b/include/misc/ocxl.h
> @@ -203,6 +203,27 @@ int ocxl_irq_set_handler(struct ocxl_context *ctx, int irq_id,
>
>  // AFU Metadata
>
> +/**
> + * ocxl_afu_map_lpc_mem() - Map the LPC system & special purpose memory for an AFU
> + * Do not call this during device discovery, as there may me multiple

s/me/be/


> + * 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
> + *
> + * Returns 0 on success, negative on failure
> + */
> +int ocxl_afu_map_lpc_mem(struct ocxl_afu *afu);
> +
> +/**
> + * ocxl_afu_lpc_mem() - Get the physical address range of LPC memory for an AFU
> + * @afu: The AFU associated with the LPC memory
> + *
> + * Returns a pointer to the resource struct for the physical address range
> + */
> +struct resource *ocxl_afu_lpc_mem(struct ocxl_afu *afu);
> +
>  /**
>   * ocxl_afu_config() - Get a pointer to the config for an AFU
>   * @afu: a pointer to the AFU to get the config for
> --
> 2.24.1
>