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

Andrew Halaney
2023-09-29T20:45:03Z

On Fri, Sep 29, 2023 at 12:22:16PM -0700, Bartosz Golaszewski wrote:
> On Fri, 29 Sep 2023 21:16:51 +0200, Andrew Halaney <ahalaney@redhat.com> said:
> > 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.
> >
>
> Gah! Thanks for finding this.
>
> Can you try the following diff?
>
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index 794388c3212f..b0d4ea237034 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -556,6 +556,7 @@ int qcom_scm_pas_init_image(u32 peripheral, const
> void *metadata, size_t size,
> dev_err(__scm->dev, "Allocation of metadata buffer failed.\n");
> return -ENOMEM;
> }
> + mdata_phys = qcom_scm_mem_to_phys(mdata_buf);
> memcpy(mdata_buf, metadata, size);
>
> ret = qcom_scm_clk_enable();
> @@ -578,7 +579,7 @@ int qcom_scm_pas_init_image(u32 peripheral, const
> void *metadata, size_t size,
> qcom_scm_mem_free(mdata_buf);
> } else if (ctx) {
> ctx->ptr = mdata_buf;
> - ctx->phys = qcom_scm_mem_to_phys(mdata_buf);
> + ctx->phys = mdata_phys;
> ctx->size = size;
> }
>
> Bart
>

For some reason that I can't explain that is still not working. It seems
the SMC call is returning !0 and then we return -EINVAL from there
with qcom_scm_remap_error().

Here's a really crummy diff of what I hacked in during lunch to debug (don't
judge my primitive debug skills):

diff --git a/drivers/firmware/qcom/qcom_scm-smc.c b/drivers/firmware/qcom/qcom_scm-smc.c
index 0d5554df1321..56eab0ae5f3a 100644
--- a/drivers/firmware/qcom/qcom_scm-smc.c
+++ b/drivers/firmware/qcom/qcom_scm-smc.c
@@ -162,6 +162,8 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
struct arm_smccc_res smc_res;
struct arm_smccc_args smc = {0};

+ dev_err(dev, "%s: %d: We are in this function\n", __func__, __LINE__);
+
smc.args[0] = ARM_SMCCC_CALL_VAL(
smccc_call_type,
qcom_smccc_convention,
@@ -174,6 +176,7 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) {
alloc_len = SCM_SMC_N_EXT_ARGS * sizeof(u64);
args_virt = qcom_scm_mem_alloc(PAGE_ALIGN(alloc_len), flag);
+ dev_err(dev, "%s: %d: Hit the unlikely case!\n", __func__, __LINE__);

if (!args_virt)
return -ENOMEM;
@@ -197,6 +200,7 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,

/* ret error check follows after args_virt cleanup*/
ret = __scm_smc_do(dev, &smc, &smc_res, atomic);
+ dev_err(dev, "%s: %d: ret: %d\n", __func__, __LINE__, ret);

if (ret)
return ret;
@@ -205,8 +209,10 @@ int __scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
res->result[0] = smc_res.a1;
res->result[1] = smc_res.a2;
res->result[2] = smc_res.a3;
+ dev_err(dev, "%s: %d: 0: %llu, 1: %llu: 2: %llu\n", __func__, __LINE__, res->result[0], res->result[1], res->result[2]);
}

+ dev_err(dev, "%s: %d: smc_res.a0: %lu\n", __func__, __LINE__, smc_res.a0);
return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0;

And that all spams dmesg successfully for most cases, but the
pas_init_image calls log this out:

[ 16.362965] remoteproc remoteproc1: powering up 1b300000.remoteproc
[ 16.364897] remoteproc remoteproc1: Booting fw image qcom/sc8280xp/LENOVO/21BX/qccdsp8280.mbn, size 3575808
[ 16.365009] qcom_scm firmware:scm: __scm_smc_call: 165: We are in this function
[ 16.365251] qcom_scm firmware:scm: __scm_smc_call: 203: ret: 0
[ 16.365256] qcom_scm firmware:scm: __scm_smc_call: 212: 0: 0, 1: 0: 2: 0
[ 16.365261] qcom_scm firmware:scm: __scm_smc_call: 215: smc_res.a0: 4291821558

At the moment I am unsure why...