Re: [PATCH v2 06/11] firmware: qcom: scm: make qcom_scm_pas_init_image() use the SCM allocator

Andrew Halaney
2023-09-29T19:17:45Z

On Thu, Sep 28, 2023 at 11:20:35AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Let's use the new SCM memory allocator to obtain a buffer for this call
> instead of using dma_alloc_coherent().
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
> drivers/firmware/qcom/qcom_scm.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index 02a773ba1383..c0eb81069847 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -532,7 +532,7 @@ static void qcom_scm_set_download_mode(bool enable)
> int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
> struct qcom_scm_pas_metadata *ctx)
> {
> - dma_addr_t mdata_phys;
> + phys_addr_t mdata_phys;

> void *mdata_buf;
> int ret;
> struct qcom_scm_desc desc = {
> @@ -544,13 +544,7 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
> };
> struct qcom_scm_res res;
>
> - /*
> - * During the scm call memory protection will be enabled for the meta
> - * data blob, so make sure it's physically contiguous, 4K aligned and
> - * non-cachable to avoid XPU violations.
> - */
> - mdata_buf = dma_alloc_coherent(__scm->dev, size, &mdata_phys,
> - GFP_KERNEL);
> + mdata_buf = qcom_scm_mem_alloc(size, GFP_KERNEL);

mdata_phys is never initialized now, and its what's being shoved into
desc.args[1] later, which I believe is what triggered the -EINVAL
with qcom_scm_call() that I reported in my cover letter reply this
morning.

Prior with the DMA API that would have been the device view of the buffer.

> if (!mdata_buf) {
> dev_err(__scm->dev, "Allocation of metadata buffer failed.\n");
> return -ENOMEM;
> @@ -574,10 +568,10 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
>
> out:
> if (ret < 0 || !ctx) {
> - dma_free_coherent(__scm->dev, size, mdata_buf, mdata_phys);
> + qcom_scm_mem_free(mdata_buf);
> } else if (ctx) {
> ctx->ptr = mdata_buf;
> - ctx->phys = mdata_phys;
> + ctx->phys = qcom_scm_mem_to_phys(mdata_buf);
> ctx->size = size;
> }
>
> @@ -594,7 +588,7 @@ void qcom_scm_pas_metadata_release(struct qcom_scm_pas_metadata *ctx)
> if (!ctx->ptr)
> return;
>
> - dma_free_coherent(__scm->dev, ctx->size, ctx->ptr, ctx->phys);
> + qcom_scm_mem_free(ctx->ptr);
>
> ctx->ptr = NULL;
> ctx->phys = 0;
> --
> 2.39.2
>