[PATCH v5 13/17] firmware: qcom_scm: provide a read-modify-write function

[Kathiravan Thirumoorthy]

On 9/10/2023 1:46 AM, Mukesh Ojha wrote:
> It was realized by Srinivas K. that there is a need of
> read-modify-write scm exported function so that it can
> be used by multiple clients.
>
> Let's introduce qcom_scm_io_update_field() which masks
> out the bits and write the passed value to that
> bit-offset. Subsequent patch will use this function.
>
> Suggested-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
> Signed-off-by: Mukesh Ojha <quic_mojha at quicinc.com>
> ---


Validated this change on IPQ9574 and IPQ53332 and system is entering 
into the download mode.

Tested-by: Kathiravan Thirumoorthy <quic_kathirav at quicinc.com> # IP9574 
and IPQ5332


>   drivers/firmware/qcom_scm.c            | 20 ++++++++++++++++++++
>   include/linux/firmware/qcom/qcom_scm.h |  2 ++
>   2 files changed, 22 insertions(+)
>
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index fde33acd46b7..5ea8fc4fd4e8 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -78,6 +78,7 @@ static const char * const qcom_scm_convention_names[] = {
>   };
>   
>   static struct qcom_scm *__scm;
> +static DEFINE_SPINLOCK(lock);
>   
>   static int qcom_scm_clk_enable(void)
>   {
> @@ -407,6 +408,25 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
>   }
>   EXPORT_SYMBOL(qcom_scm_set_remote_state);
>   
> +int qcom_scm_io_update_field(phys_addr_t addr, unsigned int mask, unsigned int val)
> +{
> +	unsigned int old, new;
> +	int ret;
> +
> +	spin_lock(&lock);
> +	ret = qcom_scm_io_readl(addr, &old);
> +	if (ret)
> +		goto unlock;
> +
> +	new = (old & ~mask) | (val & mask);
> +
> +	ret = qcom_scm_io_writel(addr, new);
> +unlock:
> +	spin_unlock(&lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(qcom_scm_io_update_field);
> +
>   static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>   {
>   	struct qcom_scm_desc desc = {
> diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
> index 250ea4efb7cb..ca41e4eb33ad 100644
> --- a/include/linux/firmware/qcom/qcom_scm.h
> +++ b/include/linux/firmware/qcom/qcom_scm.h
> @@ -84,6 +84,8 @@ extern bool qcom_scm_pas_supported(u32 peripheral);
>   
>   extern int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);
>   extern int qcom_scm_io_writel(phys_addr_t addr, unsigned int val);
> +extern int qcom_scm_io_update_field(phys_addr_t addr, unsigned int mask,
> +				    unsigned int val);
>   
>   extern bool qcom_scm_restore_sec_cfg_available(void);
>   extern int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare);