Re: [PATCH v3 3/3] bus: mhi: host: pci_generic: Add edl callback to enter EDL

[Qiang Yu <quic_qianyu@xxxxxxxxxxx>]

On 4/16/2024 7:53 AM, Mayank Rana wrote:
> Hi Qiang
>
> On 4/15/2024 1:49 AM, Qiang Yu wrote:
> > Add mhi_pci_generic_edl_trigger as edl_trigger for some devices (eg. 
> > SDX65)
> > to enter EDL mode by writing the 0xEDEDEDED cookie to the channel 91
> > doorbell register and forcing an SOC reset afterwards.
> >
> > Signed-off-by: Qiang Yu <quic_qianyu@xxxxxxxxxxx>
> > ---
> >   drivers/bus/mhi/host/pci_generic.c | 47 
> > ++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 47 insertions(+)
> >
> > diff --git a/drivers/bus/mhi/host/pci_generic.c 
> > b/drivers/bus/mhi/host/pci_generic.c
> > index 51639bf..cbf8a58 100644
> > --- a/drivers/bus/mhi/host/pci_generic.c
> > +++ b/drivers/bus/mhi/host/pci_generic.c
> > @@ -27,12 +27,19 @@
> >   #define PCI_VENDOR_ID_THALES    0x1269
> >   #define PCI_VENDOR_ID_QUECTEL    0x1eac
> >   +#define MHI_EDL_DB            91
> > +#define MHI_EDL_COOKIE            0xEDEDEDED
> > +
> > +/* Device can enter EDL by first setting edl cookie then issuing 
> > inband reset*/
> > +#define MHI_PCI_GENERIC_EDL_TRIGGER    BIT(0)
> > +
> >   /**
> >    * struct mhi_pci_dev_info - MHI PCI device specific information
> >    * @config: MHI controller configuration
> >    * @name: name of the PCI module
> >    * @fw: firmware path (if any)
> >    * @edl: emergency download mode firmware path (if any)
> > + * @edl_trigger: each bit represents a different way to enter EDL
> >    * @bar_num: PCI base address register to use for MHI MMIO register 
> > space
> >    * @dma_data_width: DMA transfer word size (32 or 64 bits)
> >    * @mru_default: default MRU size for MBIM network packets
> > @@ -44,6 +51,7 @@ struct mhi_pci_dev_info {
> >       const char *name;
> >       const char *fw;
> >       const char *edl;
> > +    unsigned int edl_trigger;
> >       unsigned int bar_num;
> >       unsigned int dma_data_width;
> >       unsigned int mru_default;
> > @@ -292,6 +300,7 @@ static const struct mhi_pci_dev_info 
> > mhi_qcom_sdx75_info = {
> >       .name = "qcom-sdx75m",
> >       .fw = "qcom/sdx75m/xbl.elf",
> >       .edl = "qcom/sdx75m/edl.mbn",
> > +    .edl_trigger = MHI_PCI_GENERIC_EDL_TRIGGER,
> >       .config = &modem_qcom_v2_mhiv_config,
> >       .bar_num = MHI_PCI_DEFAULT_BAR_NUM,
> >       .dma_data_width = 32,
> > @@ -302,6 +311,7 @@ static const struct mhi_pci_dev_info 
> > mhi_qcom_sdx65_info = {
> >       .name = "qcom-sdx65m",
> >       .fw = "qcom/sdx65m/xbl.elf",
> >       .edl = "qcom/sdx65m/edl.mbn",
> > +    .edl_trigger = MHI_PCI_GENERIC_EDL_TRIGGER,
> >       .config = &modem_qcom_v1_mhiv_config,
> >       .bar_num = MHI_PCI_DEFAULT_BAR_NUM,
> >       .dma_data_width = 32,
> > @@ -312,6 +322,7 @@ static const struct mhi_pci_dev_info 
> > mhi_qcom_sdx55_info = {
> >       .name = "qcom-sdx55m",
> >       .fw = "qcom/sdx55m/sbl1.mbn",
> >       .edl = "qcom/sdx55m/edl.mbn",
> > +    .edl_trigger = MHI_PCI_GENERIC_EDL_TRIGGER,
> >       .config = &modem_qcom_v1_mhiv_config,
> >       .bar_num = MHI_PCI_DEFAULT_BAR_NUM,
> >       .dma_data_width = 32,
> > @@ -928,6 +939,39 @@ static void health_check(struct timer_list *t)
> >       mod_timer(&mhi_pdev->health_check_timer, jiffies + 
> > HEALTH_CHECK_PERIOD);
> >   }
> >   +static int mhi_pci_generic_edl_trigger(struct mhi_controller 
> > *mhi_cntrl)
> > +{
> > +    void __iomem *base = mhi_cntrl->regs;
> > +    void __iomem *edl_db;
> > +    int ret;
> > +    u32 val;
> > +
> > +    ret = mhi_device_get_sync(mhi_cntrl->mhi_dev);
> > +    if (ret) {
> > +        dev_err(mhi_cntrl->cntrl_dev, "Wake up device fail before 
> > trigger EDL\n");
> > +        return ret;
> > +    }
> > +
> > +    pm_wakeup_event(&mhi_cntrl->mhi_dev->dev, 0);
> > +    mhi_cntrl->runtime_get(mhi_cntrl);
> > +
> > +    ret = mhi_get_channel_doorbell(mhi_cntrl, &val);
> > +    if (ret)
> > +        return ret;
> Don't we need error handling part here i.e. calling 
> mhi_cntrl->runtime_put() as well mhi_device_put() ?

Hi Mayank

After soc_reset, device will reboot to EDL mode and MHI state will be 
SYSERR. So host will fail to suspend
anyway. The "error handling" we need here is actually to enter EDL mode, 
this will be done by SYSERR irq.
Here, mhi_cntrl->runtime_put() and mhi_device_put() are only to balance 
mhi_cntrl->runtime_get() and
mhi_device_get_sync().

Thanks,
Qiang

> > +    edl_db = base + val + (8 * MHI_EDL_DB);
> > +
> > +    mhi_cntrl->write_reg(mhi_cntrl, edl_db + 4, 
> > upper_32_bits(MHI_EDL_COOKIE));
> > +    mhi_cntrl->write_reg(mhi_cntrl, edl_db, 
> > lower_32_bits(MHI_EDL_COOKIE));
> > +
> > +    mhi_soc_reset(mhi_cntrl);
> > +
> > +    mhi_cntrl->runtime_put(mhi_cntrl);
> > +    mhi_device_put(mhi_cntrl->mhi_dev);
> > +
> > +    return 0;
> > +}
> > +
> >   static int mhi_pci_probe(struct pci_dev *pdev, const struct 
> > pci_device_id *id)
> >   {
> >       const struct mhi_pci_dev_info *info = (struct mhi_pci_dev_info 
> > *) id->driver_data;
> > @@ -962,6 +1006,9 @@ static int mhi_pci_probe(struct pci_dev *pdev, 
> > const struct pci_device_id *id)
> >       mhi_cntrl->runtime_put = mhi_pci_runtime_put;
> >       mhi_cntrl->mru = info->mru_default;
> >   +    if (info->edl_trigger & MHI_PCI_GENERIC_EDL_TRIGGER)
> > +        mhi_cntrl->edl_trigger = mhi_pci_generic_edl_trigger;
> > +
> >       if (info->sideband_wake) {
> >           mhi_cntrl->wake_get = mhi_pci_wake_get_nop;
> >           mhi_cntrl->wake_put = mhi_pci_wake_put_nop;
> Regards,
> Mayank