Re: [PATCH v4 19/21] firmware: scm: Modify only the download bits in TCSR register

Konrad Dybcio
2023-06-28T15:20:49Z

On 28.06.2023 14:34, Mukesh Ojha wrote:
> CrashDump collection is based on the DLOAD bit of TCSR register.
> To retain other bits, we read the register and modify only the
> DLOAD bit as the other bits have their own significance.
>
> Co-developed-by: Poovendhan Selvaraj <quic_poovendh@quicinc.com>
> Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
> ---
> drivers/firmware/qcom_scm.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index 104d86e49b97..a9ff77d16c42 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -30,6 +30,11 @@ module_param(download_mode, bool, 0);
> #define SCM_HAS_IFACE_CLK BIT(1)
> #define SCM_HAS_BUS_CLK BIT(2)
>
> +#define QCOM_DOWNLOAD_FULLDUMP 0x1
> +#define QCOM_DOWNLOAD_NODUMP 0x0
> +#define QCOM_DOWNLOAD_MODE_SHIFT 4
> +#define QCOM_DOWNLOAD_MODE_MASK 0x30
GENMASK and then FIELD_PREP below?

> +
> struct qcom_scm {
> struct device *dev;
> struct clk *core_clk;
> @@ -440,6 +445,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
> static void qcom_scm_set_download_mode(bool enable)
> {
> bool avail;
> + int val;
What's wrong with initializing it in the same line as ret?

> int ret = 0;
>
> avail = __qcom_scm_is_call_available(__scm->dev,
> @@ -448,8 +454,10 @@ static void qcom_scm_set_download_mode(bool enable)
> if (avail) {
> ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
> } else if (__scm->dload_mode_addr) {
> - ret = qcom_scm_io_writel(__scm->dload_mode_addr,
> - enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0);
> + val = (enable ? QCOM_DOWNLOAD_FULLDUMP : QCOM_DOWNLOAD_NODUMP);
unnecessary braces

Konrad
> + val <<= QCOM_DOWNLOAD_MODE_SHIFT;
> + ret = qcom_scm_io_update_field(__scm->dload_mode_addr,
> + QCOM_DOWNLOAD_MODE_MASK, val);
> } else {
> dev_err(__scm->dev,
> "No available mechanism for setting download mode\n");