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SubjectRe: [PATCH v2 05/16] remoteproc: modify rproc_handle_carveout to support preallocated region
On Thu 30 Nov 08:46 PST 2017, Loic Pallardy wrote:

> In current version rproc_handle_carveout function support only dynamic
> region allocation.
> This patch extends rproc_handle_carveout function to support different carveout
> configurations:
> - fixed DA and fixed PA: check if already part of pre-registered carveouts
> (platform driver). If no, return error.
> - fixed DA and any PA: check if already part of pre-allocated carveouts
> (platform driver). If not found and rproc supports iommu, continue with
> dynamic allocation (DA will be used for iommu programming), else return
> error as no way to force DA.
> - any DA and any PA: use original dynamic allocation
>
> Signed-off-by: Loic Pallardy <loic.pallardy@st.com>
> ---
> drivers/remoteproc/remoteproc_core.c | 40 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 78525d1..515a17a 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -184,6 +184,10 @@ void *rproc_da_to_va(struct rproc *rproc, u64 da, int len)
> struct rproc_mem_entry *carveout;
> void *ptr = NULL;
>
> + /*
> + * da_to_va platform driver is deprecated. Driver should register
> + * carveout thanks to rproc_add_carveout function
> + */

I think this comment is unrelated to the rest of this patch. I also
think that at the end of the carveout-rework we should have a patch
removing this ops.

> if (rproc->ops->da_to_va) {
> ptr = rproc->ops->da_to_va(rproc, da, len);
> if (ptr)
> @@ -677,6 +681,7 @@ static int rproc_handle_carveout(struct rproc *rproc,
> struct rproc_mem_entry *carveout, *mapping;
> struct device *dev = &rproc->dev;
> dma_addr_t dma;
> + phys_addr_t pa;
> void *va;
> int ret;
>
> @@ -698,6 +703,41 @@ static int rproc_handle_carveout(struct rproc *rproc,
> if (!carveout)
> return -ENOMEM;
>
> + /* Check carveout rsc already part of a registered carveout */
> + if (rsc->da != FW_RSC_ADDR_ANY) {

As mentioned before, I consider it perfectly viable for rsc->da to be
ANY and the driver providing a fixed carveout.

> + va = rproc_find_carveout_by_da(rproc, rsc->da, rsc->len);
> +
> + if (va) {

In a system with an iommu it's possible that rsc->len is larger than
some carveout->len and va is NULL here so we fall through, allocate some
memory and remap a segment of the carveout. (Or hopefully fails
attempting).

> + /* Registered region found */
> + pa = rproc_va_to_pa(va);
> + if (rsc->pa != FW_RSC_ADDR_ANY && rsc->pa != (u32)pa) {
> + /* Carveout doesn't match request */
> + dev_err(dev->parent,
> + "Failed to find carveout fitting da and pa\n");
> + return -ENOMEM;
> + }
> +
> + /* Update rsc table with physical address */
> + rsc->pa = (u32)pa;
> +
> + /* Update carveouts list */
> + carveout->va = va;
> + carveout->len = rsc->len;
> + carveout->da = rsc->da;
> + carveout->priv = (void *)CARVEOUT_RSC;
> +
> + list_add_tail(&carveout->node, &rproc->carveouts);

rproc_find_carveout_by_da() will return a reference into a carveout, now
we add another overlapping carveout into the same list.


I think it would be saner to not allow the resource table to describe
subsets of carveouts registered by the driver.

In which case this would better find a carveout by name or exact da,
then check that the pa, da, len and rsc->flags are adequate.

> +
> + return 0;
> + }
> +
> + if (!rproc->domain) {

Currently this function ignore invalid values of da when !domain, so I
think it would be good you can submit this sanity check in it's own
patch so that anyone bisecting this would know why their broken firmware
suddenly isn't loadable.

> + dev_err(dev->parent,
> + "Bad carveout rsc configuration\n");
> + return -ENOMEM;
> + }
> + }
> +

Regards,
Bjorn

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