Re: [PATCH v2 07/27] ocxl: Add functions to map/unmap LPC memory

Jonathan Cameron
2020-02-03T12:49:48Z

On Tue, 3 Dec 2019 14:46:35 +1100
Alastair D'Silva <alastair@au1.ibm.com> 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/ocxl_internal.h | 3 ++
> include/misc/ocxl.h | 18 +++++++++++
> 4 files changed, 75 insertions(+)
>
> 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);
> +

If we are being fussy, this block has nothing todo with the rest of the patch
so we should be seeing it here.

> return 0;
> }
>
> diff --git a/drivers/misc/ocxl/core.c b/drivers/misc/ocxl/core.c
> index 2531c6cf19a0..98611faea219 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_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) {

I was happy with the explicit check on 0 above, but we should be consistent. Either
we make use of 0 == false, or we don't and explicitly check vs 0.

Hence

if (afu->config.pc_mem_size != 0) {

here or

if (!(afu->config.pc_mem_size + afu->config.special_purpose_mem_size))
return 0;

above.

> + 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_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;
> +
> + 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 +300,7 @@ 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);

Hmm. This breaks the existing balance between configure_afu and deconfigure_afu.

Given comments below on why we don't do map_lpc_mem in the afu bring up
(as it's a shared operation) it seems to me that we should be doing this
outside of the afu deconfigure. Perhaps ocxl_function_close is appropriate?
I don't know this infrastructure well enough to be sure.

If it does need to be here, then a comment to give more info on
why would be great!

> 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 20b417e00949..9f4b47900e62 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 06dd5839e438..6f7c02f0d5e3 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
Run kernel-doc over these files and fix all the errors + warnings.

@afu: ..

and missing function name etc.

> + */
> +extern int ocxl_afu_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
> *