Re: [PATCH] firmware: qcom_scm: Fix legacy convention SCM accessors

[Elliot Berman <eberman@codeaurora.org>]

For the Qualcomm TrustZone firmwares which I am familiar with:

Reviewed-by: Elliot Berman <eberman@codeaurora.org>

On 7/4/2020 10:23 AM, Jonathan McDowell wrote:
> The move to a combined driver for the QCOM SCM hardware changed the
> io_writel and io_readl helpers to use non-atomic calls, despite the
> commit message saying that atomic was a better option. This breaks these
> helpers on hardware that uses the old legacy convention (access fails
> with a -95 return code). Switch back to using the atomic calls.
> 
> Observed as a failure routing GPIO interrupts to the Apps processor on
> an IPQ8064; fix is confirmed as correctly allowing the interrupts to be
> routed and observed.
> 
> Fixes: 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jonathan McDowell <noodles@earth.li>
> ---
>  drivers/firmware/qcom_scm.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 0e7233a20f34..d4fda210adfe 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -391,7 +391,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>  
>  	desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
>  
> -	return qcom_scm_call(__scm->dev, &desc, NULL);
> +	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>  }
>  
>  static void qcom_scm_set_download_mode(bool enable)
> @@ -650,7 +650,7 @@ int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val)
>  	int ret;
>  
>  
> -	ret = qcom_scm_call(__scm->dev, &desc, &res);
> +	ret = qcom_scm_call_atomic(__scm->dev, &desc, &res);
>  	if (ret >= 0)
>  		*val = res.result[0];
>  
> @@ -669,8 +669,7 @@ int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
>  		.owner = ARM_SMCCC_OWNER_SIP,
>  	};
>  
> -
> -	return qcom_scm_call(__scm->dev, &desc, NULL);
> +	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>  }
>  EXPORT_SYMBOL(qcom_scm_io_writel);
>  
> 

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project