Messages in this thread Patch in this message | | | Date | Mon, 20 Mar 2023 17:35:53 +0000 | Subject | Re: [PATCH v3 1/5] firmware: qcom_scm: provide a read-modify-write function | From | Srinivas Kandagatla <> |
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On 17/03/2023 16:27, Mukesh Ojha wrote: > It was released 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@linaro.org> > Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com> > --- > drivers/firmware/qcom_scm.c | 15 +++++++++++++++ > include/linux/firmware/qcom/qcom_scm.h | 2 ++ > 2 files changed, 17 insertions(+) > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > index 3e020d1..aca2556 100644 > --- a/drivers/firmware/qcom_scm.c > +++ b/drivers/firmware/qcom_scm.c > @@ -407,6 +407,21 @@ 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; > + > + ret = qcom_scm_io_readl(addr, &old); > + if (ret) > + return ret; > + > + new = (old & ~mask) | val;
thanks for doing this,
With field semantics, val should be shifted within the function, so the caller only sets value for field rather than passing a shifted value. so this should be:
new = (old & ~mask) | (val << ffs(mask) - 1);
--srini
> + > + return qcom_scm_io_writel(addr, new); > +} > +EXPORT_SYMBOL(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 1e449a5..203a781 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);
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