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

Elliot Berman
2023-09-29T22:49:03Z

Hi Andrew,

On 9/29/2023 1:44 PM, Andrew Halaney wrote:
> 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):
>

I don't know what you're talking about :-)

> 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...
>
Does the issue appear right after taking patch 6 or does it only appear after taking
the whole series? If it's just to this patch, then maybe something wrong with
the refactor: shm bridge isn't enabled at this point in the series.