| Message ID | 1680076012-10785-2-git-send-email-quic_mojha@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | Refactor to support multiple download mode | expand |
Wed, Mar 29, 2023 at 01:16:48PM +0530, Mukesh Ojha kirjoitti: > 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. ... > + new = (old & ~mask) | val << (ffs(mask) - 1); It's a bit non-standard to see left shift here instead of masking. new = (old & ~mask) | (val & mask); is usual pattern. Note as well that your code is prone to subtle mistakes when overflow may easily override bits outside the mask. > + return qcom_scm_io_writel(addr, new); > +}
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index 5f281cb..cb0bc32 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 << (ffs(mask) - 1); + + 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);
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@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(+)