Messages in this thread | | | Date | Wed, 8 Mar 2023 15:06:29 +0000 | Subject | Re: [PATCH v2 2/4] firmware: scm: Modify only the DLOAD bit in TCSR register for download mode | From | Srinivas Kandagatla <> |
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On 01/03/2023 09:55, 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. > > Originally-by: Poovendhan Selvaraj <quic_poovendh@quicinc.com> > Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com> > --- > Changes in v2: > - Addressed comment made by Bjorn. > - Added download mask from patch 3 to this. > > drivers/firmware/qcom_scm.c | 17 +++++++++++++++-- > 1 file changed, 15 insertions(+), 2 deletions(-) > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > index 51eb853..c9f1fad 100644 > --- a/drivers/firmware/qcom_scm.c > +++ b/drivers/firmware/qcom_scm.c > @@ -27,6 +27,8 @@ module_param(download_mode, bool, 0); > #define SCM_HAS_IFACE_CLK BIT(1) > #define SCM_HAS_BUS_CLK BIT(2) > > +#define QCOM_DOWNLOAD_MODE_MASK 0x30 > + > struct qcom_scm { > struct device *dev; > struct clk *core_clk; > @@ -419,6 +421,7 @@ static void qcom_scm_set_download_mode(bool enable) > { > bool avail; > int ret = 0; > + u32 val; > > avail = __qcom_scm_is_call_available(__scm->dev, > QCOM_SCM_SVC_BOOT, > @@ -426,8 +429,18 @@ 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); > + ret = qcom_scm_io_readl(__scm->dload_mode_addr, &val); > + if (ret) { > + dev_err(__scm->dev, > + "failed to read dload mode address value: %d\n", ret); > + return; > + } > + > + val &= ~QCOM_DOWNLOAD_MODE_MASK; > + if (enable) > + val |= QCOM_SCM_BOOT_SET_DLOAD_MODE; > + > + ret = qcom_scm_io_writel(__scm->dload_mode_addr, val);
This is the second instance of such pattern of usage one is already in ./drivers/pinctrl/qcom/pinctrl-msm.c
I think it makes sense to move setting fields in register to a dedicated function like this:
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);
then we could use it like this: ret = qcom_scm_io_update_field(__scm->dload_mode_addr, QCOM_DOWNLOAD_MODE_MASK, dl_mode)
--srini > } else { > dev_err(__scm->dev, > "No available mechanism for setting download mode\n");
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