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SubjectRe: [PATCH v3 07/27] ocxl: Add functions to map/unmap LPC memory
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On 21/2/20 2:27 pm, 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/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;

I'd prefer the comparison here to be:

afu->config.lpc_mem_size == 0 &&
afu->config.special_purpose_mem_size == 0

so a reader doesn't have to think about what this means.

> +
> + 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;

Maybe not for this series - hmm, I wonder if we should print a warning
somewhere (maybe in read_afu_lpc_memory_info()?) if we see the case
where (lpc_mem_offset > 0 && lpc_mem_size == 0). Likewise for special
purpose?

> + 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);

What's the point of this function? A layer of indirection just in case
we need it in future?

> +
> +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 d0c8c4838f42..ce0cac1da416 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

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
>

--
Andrew Donnellan OzLabs, ADL Canberra
ajd@linux.ibm.com IBM Australia Limited

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