Messages in this thread | | | From | Aisheng Dong <> | Subject | RE: [PATCH] clk: imx: introduce imx_clk_hw_critical | Date | Fri, 24 Apr 2020 01:59:02 +0000 |
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> From: Peng Fan <peng.fan@nxp.com> > Sent: Friday, April 24, 2020 9:08 AM > > > Subject: RE: [PATCH] clk: imx: introduce imx_clk_hw_critical > > > > > From: Peng Fan <peng.fan@nxp.com> > > > Sent: Thursday, April 23, 2020 6:54 PM > > > > > > > Subject: RE: [PATCH] clk: imx: introduce imx_clk_hw_critical > > > > > > > > > From: Peng Fan <peng.fan@nxp.com> > > > > > Sent: Thursday, April 23, 2020 2:52 PM > > > > > > > > > > To i.MX8M SoC, there is an case is when running dual OSes with > > > > > hypervisor, the clk of the hardware that passthrough to the 2nd > > > > > OS needs to be setup by 1st Linux OS. > > > > > So detect clock-critical from ccm node and enable the clocks to > > > > > let the 2nd OS could use the hardware without touch CCM module. > > > > > > > > > > Signed-off-by: Peng Fan <peng.fan@nxp.com> > > > > > --- > > > > > drivers/clk/imx/clk.c | 19 +++++++++++++++++++ > > > > > drivers/clk/imx/clk.h > > > > > | 1 > > > > > + > > > > > 2 files changed, 20 insertions(+) > > > > > > > > > > diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c index > > > > > 87ab8db3d282..ec7d422540c1 100644 > > > > > --- a/drivers/clk/imx/clk.c > > > > > +++ b/drivers/clk/imx/clk.c > > > > > @@ -177,3 +177,22 @@ static int __init imx_clk_disable_uart(void) > > > > > return 0; > > > > > } > > > > > late_initcall_sync(imx_clk_disable_uart); > > > > > + > > > > > +int imx_clk_hw_critical(struct device_node *np, struct clk_hw * > > > > > +const > > > > > +hws[]) { > > > > > + struct property *prop; > > > > > + const __be32 *cur; > > > > > + u32 idx; > > > > > + int ret; > > > > > + > > > > > + if (!np || !hws) > > > > > + return -EINVAL; > > > > > + > > > > > + of_property_for_each_u32(np, "clock-critical", prop, cur, idx) > > > > > +{ > > > > > > > > Is there a binding for it already? > > > > > > I think clock-critical is a common bindings? See of_clk_detect_critical. > > > Please review whether this approach is acceptable, if do need > > > bindings, I could add that in v2. > > > > > > > I'm ok if it's a common binding already supported by current clk framework. > > But it seems to be more like a common clk feature rather than platform > > feature. > > Here is to use it for dual Linux case running on i.MX plaforms. > It is to replace the init-on-array property in downstream kernel. > > The recommended critical clock is using CLK_IS_CRITICAL flag in clk driver, not > use clock-critical property. >
Clock-critical property seems DT usage of CLK_IS_CRITICAL flag and pure platform independent. So I wonder if this feature could be added into of_clk_add_hw_provider.
> But here, we could not use CLK_IS_CRITICAL, because when support dual OSes, > it is not flexible, and it will affect non hypervisor case. >
A bit confuing because you said the critical-clock property will only be used by Hypervisor dts, then how to affect non hypervisor cases?
> > Also a bit strange that why I did not find the binding doc in latest kernel. > > Maybe Stephen could comment more. > > It is used here. > https://elixir.bootlin.com/linux/v5.7-rc2/source/drivers/clk/clk.c#L4891
Yes, I also saw it, but didn't find binding doc.
Regards Aisheng
> > > > > BTW, if using this for dual OSes case, will those critical clocks > > affect the normal users that not booting the second OS? > > No. dual os using x-root.dts, not x.dts. critical-clock will be push in x-root.dts. > > Thanks, > Peng. > > > > > Regards > > Aisheng > > > > > Thanks, > > > Peng. > > > > > > > > > > > Regards > > > > Aisheng > > > > > > > > > + ret = clk_prepare_enable(hws[idx]->clk); > > > > > + if (ret) > > > > > + return ret; > > > > > + } > > > > > + > > > > > + return 0; > > > > > +} > > > > > diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h index > > > > > d4ea1609bcb7..701d7440f98c 100644 > > > > > --- a/drivers/clk/imx/clk.h > > > > > +++ b/drivers/clk/imx/clk.h > > > > > @@ -9,6 +9,7 @@ extern spinlock_t imx_ccm_lock; > > > > > > > > > > void imx_check_clocks(struct clk *clks[], unsigned int count); > > > > > void imx_check_clk_hws(struct clk_hw *clks[], unsigned int > > > > > count); > > > > > +int imx_clk_hw_critical(struct device_node *np, struct clk_hw * > > > > > +const hws[]); > > > > > void imx_register_uart_clocks(struct clk ** const clks[]); > > > > > void imx_mmdc_mask_handshake(void __iomem *ccm_base, unsigned > > > > > int > > chn); > > > > > void imx_unregister_clocks(struct clk *clks[], unsigned int > > > > > count); > > > > > -- > > > > > 2.16.4
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