Re: [PATCH v2 1/4] PCI: pciehp: Add pciehp_set_indicators() to jointly set LED indicators

[sathyanarayanan kuppuswamy <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>]

Hi,

On 8/12/19 11:25 AM, sathyanarayanan kuppuswamy wrote:
> Hi,
>
> On 8/11/19 12:59 PM, Denis Efremov wrote:
> > Add pciehp_set_indicators() to set power and attention indicators with a
> > single register write. Thus, avoiding waiting twice for Command 
> > Complete.
> > enum pciehp_indicator introduced to switch between the indicators 
> > statuses.
> >
> > Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
> > ---
> >   drivers/pci/hotplug/pciehp.h     | 14 ++++++++++++
> >   drivers/pci/hotplug/pciehp_hpc.c | 38 ++++++++++++++++++++++++++++++++
> >   include/uapi/linux/pci_regs.h    |  2 ++
> >   3 files changed, 54 insertions(+)
> >
> > diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
> > index 8c51a04b8083..17305a6f01f1 100644
> > --- a/drivers/pci/hotplug/pciehp.h
> > +++ b/drivers/pci/hotplug/pciehp.h
> > @@ -150,6 +150,17 @@ struct controller {
> >   #define NO_CMD_CMPL(ctrl)    ((ctrl)->slot_cap & PCI_EXP_SLTCAP_NCCS)
> >   #define PSN(ctrl)        (((ctrl)->slot_cap & PCI_EXP_SLTCAP_PSN) 
> > >> 19)
> >   +enum pciehp_indicator {
> > +    ATTN_NONE  = -1,
> > +    ATTN_ON    =  1,
> > +    ATTN_BLINK =  2,
> > +    ATTN_OFF   =  3,
> > +    PWR_NONE   = -1,
> > +    PWR_ON     =  1,
> > +    PWR_BLINK  =  2,
> > +    PWR_OFF    =  3,
> > +};
> > +
> >   void pciehp_request(struct controller *ctrl, int action);
> >   void pciehp_handle_button_press(struct controller *ctrl);
> >   void pciehp_handle_disable_request(struct controller *ctrl);
> > @@ -167,6 +178,9 @@ int pciehp_power_on_slot(struct controller *ctrl);
> >   void pciehp_power_off_slot(struct controller *ctrl);
> >   void pciehp_get_power_status(struct controller *ctrl, u8 *status);
> >   +void pciehp_set_indicators(struct controller *ctrl,
> > +               enum pciehp_indicator pwr,
> > +               enum pciehp_indicator attn);
> >   void pciehp_set_attention_status(struct controller *ctrl, u8 status);
> >   void pciehp_get_latch_status(struct controller *ctrl, u8 *status);
> >   int pciehp_query_power_fault(struct controller *ctrl);
> > diff --git a/drivers/pci/hotplug/pciehp_hpc.c 
> > b/drivers/pci/hotplug/pciehp_hpc.c
> > index bd990e3371e3..5a690b1579ec 100644
> > --- a/drivers/pci/hotplug/pciehp_hpc.c
> > +++ b/drivers/pci/hotplug/pciehp_hpc.c
> > @@ -443,6 +443,44 @@ void pciehp_set_attention_status(struct 
> > controller *ctrl, u8 value)
> >            pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_cmd);
> >   }
> >   +void pciehp_set_indicators(struct controller *ctrl,
> > +               enum pciehp_indicator pwr,
> > +               enum pciehp_indicator attn)
> > +{
> > +    u16 cmd = 0, mask = 0;
> > +
> > +    if ((!PWR_LED(ctrl)  || pwr  == PWR_NONE) &&
> > +        (!ATTN_LED(ctrl) || attn == ATTN_NONE))
> > +        return;

Also I think this condition needs to expand to handle the case whether 
pwr != PWR_NONE and !PWR_LED(ctrl) is true.

you need to return for case, pwr = PWR_ON, !PWR_LED(ctrl)=true , 
!ATTN_LED(ctrl)=false, attn=on

> > +
> > +    switch (pwr) {
> > +    case PWR_ON:
> > +    case PWR_BLINK:
> > +    case PWR_OFF:
> > +        cmd = pwr << PCI_EXP_SLTCTL_PWR_IND_OFFSET;
> > +        mask = PCI_EXP_SLTCTL_PIC;
> > +        break;
> > +    default:
> > +        break;
> > +    }
> Do we need to switch case here ? if (pwr > 0) {} should work right ?
> > +
> > +    switch (attn) {
> > +    case ATTN_ON:
> > +    case ATTN_BLINK:
> > +    case ATTN_OFF:
> > +        cmd |= attn << PCI_EXP_SLTCTL_ATTN_IND_OFFSET;
> > +        mask |= PCI_EXP_SLTCTL_AIC;
> > +        break;
> > +    default:
> > +        break;
> > +    }
> Same here. if (attn > 0) {}
> > +
> > +    pcie_write_cmd_nowait(ctrl, cmd, mask);
> > +    ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
> > +         pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
> > +         cmd);
> > +}
> > +
> >   void pciehp_green_led_on(struct controller *ctrl)
> >   {
> >       if (!PWR_LED(ctrl))
> > diff --git a/include/uapi/linux/pci_regs.h 
> > b/include/uapi/linux/pci_regs.h
> > index f28e562d7ca8..18722d1f54a0 100644
> > --- a/include/uapi/linux/pci_regs.h
> > +++ b/include/uapi/linux/pci_regs.h
> > @@ -591,10 +591,12 @@
> >   #define  PCI_EXP_SLTCTL_CCIE    0x0010    /* Command Completed 
> > Interrupt Enable */
> >   #define  PCI_EXP_SLTCTL_HPIE    0x0020    /* Hot-Plug Interrupt 
> > Enable */
> >   #define  PCI_EXP_SLTCTL_AIC    0x00c0    /* Attention Indicator 
> > Control */
> > +#define  PCI_EXP_SLTCTL_ATTN_IND_OFFSET 0x6   /* Attention Indicator 
> > Offset */
> >   #define  PCI_EXP_SLTCTL_ATTN_IND_ON    0x0040 /* Attention 
> > Indicator on */
> >   #define  PCI_EXP_SLTCTL_ATTN_IND_BLINK 0x0080 /* Attention 
> > Indicator blinking */
> >   #define  PCI_EXP_SLTCTL_ATTN_IND_OFF   0x00c0 /* Attention 
> > Indicator off */
> >   #define  PCI_EXP_SLTCTL_PIC    0x0300    /* Power Indicator Control */
> > +#define  PCI_EXP_SLTCTL_PWR_IND_OFFSET 0x8    /* Power Indicator 
> > Offset */
> >   #define  PCI_EXP_SLTCTL_PWR_IND_ON     0x0100 /* Power Indicator on */
> >   #define  PCI_EXP_SLTCTL_PWR_IND_BLINK  0x0200 /* Power Indicator 
> > blinking */
> >   #define  PCI_EXP_SLTCTL_PWR_IND_OFF    0x0300 /* Power Indicator 
> > off */
--
Sathyanarayanan Kuppuswamy
Linux kernel developer