NOC (interconnect) lockup on i.MX8MP during resume

[Alexander Stein]

Hi Ahmad,

Am Donnerstag, 9. März 2023, 16:03:26 CET schrieb Ahmad Fatoum:
> Hello Alexander,
> 
> On 09.03.23 15:57, Alexander Stein wrote:
> > Hi,
> > 
> > while debugging another issue regarding suspend/resume I noticed that the
> > imx interconnect driver locks up the system when writing into registers.
> > This happens during resume of the 'g2' power domain.
> > imx8m_blk_ctrl_power_on() will eventually call down to
> > imx_icc_node_set(). Using the debug diff furthe down I get this output:
> > 
> > [   71.493062] imx_icc_node_set: node: VPU G2
> > [   71.497163] imx_icc_node_set: peak_bw: 1
> > [   71.501091] imx_icc_node_set: prio: 0x80000303
> > <freeze here>
> > 
> > Unfortunately there is absolutely no documentation regarding NOC in the
> > reference manual, so no idea whats happening here.
> > This is on next-20230309 using imx8mp-tqma8mpql-mba8mpxl.dts with USB
> > disabled (prevents suspend) and Ethernet-PHY-IRQ disabled (the issue I'm
> > tackling).
> > Is there some idea what do in order to support resume on i.MX8MP?
> 
> Could it be that you don't have a fully featured 8MP, but a 8MPUL
> or 8MPL, which lacks VPUs? In that case, it's not enough to disable
> the VPU nodes in the DT, but you need to disable the VPU power domains as
> well.

That's reasonable to question this, but in this case this is a full-fledged 
8MP. I just noticed that during boot those settings are done as well and there 
I get the (expected) output:

[   12.696371] imx_icc_node_set: node: VPU G2
[   12.700472] imx_icc_node_set: peak_bw: 1
[   12.704401] imx_icc_node_set: prio: 0x80000303
[   12.708850] imx_icc_node_set: mode: 0x0
[   12.712691] imx_icc_node_set: ext_control: #0
[   12.717053] imx_icc_node_set: node: NOC_VIDEO
[   12.721419] imx_icc_node_set: peak_bw: 1

So there is something wrong during resume. Both clk_ignore_unused 
pd_ignore_unused did not help.

Best regards,
Alexander

> Cheers,
> Ahmad
> 
> > Best regards,
> > Alexander
> > 
> > ---8<---
> > diff --git a/drivers/interconnect/imx/imx.c
> > b/drivers/interconnect/imx/imx.c index 979ed610f704..93ec79cc7c06 100644
> > --- a/drivers/interconnect/imx/imx.c
> > +++ b/drivers/interconnect/imx/imx.c
> > @@ -44,13 +44,18 @@ static int imx_icc_node_set(struct icc_node *node)
> > 
> >         u32 prio;
> >         u64 freq;
> > 
> > +       pr_info("%s: node: %s\n", __func__, node->name);
> > +       pr_info("%s: peak_bw: %u\n", __func__, node->peak_bw);
> > 
> >         if (node_data->setting && node->peak_bw) {
> >         
> >                 base = node_data->setting->reg +
> >                 node_data->imx_provider->noc_base;
> >                 if (node_data->setting->mode == IMX_NOC_MODE_FIXED) {
> >                 
> >                         prio = node_data->setting->prio_level;
> >                         prio = PRIORITY_COMP_MARK | (prio << 8) | prio;
> > 
> > +                       pr_info("%s: prio: %#x\n", __func__, prio);
> > 
> >                         writel(prio, base + IMX_NOC_PRIO_REG);
> > 
> > +                       pr_info("%s: mode: %#x\n", __func__,
> > node_data->setting->mode);> 
> >                         writel(node_data->setting->mode, base +
> >                         IMX_NOC_MODE_REG);
> > 
> > +                       pr_info("%s: ext_control: #%x\n", __func__,
> > node_data->setting->ext_control);> 
> >                         writel(node_data->setting->ext_control, base +
> >                         IMX_NOC_EXT_CTL_REG);
> >                         dev_dbg(dev, "%s: mode: 0x%x, prio: 0x%x,
> >                         ext_control: 0x%x\n",
> >                         
> >                                 node_data->desc->name,
> >                                 node_data->setting->mode, prio,
> > 
> > ---8<---


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