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

sathyanarayanan kuppuswamy
2019-08-12T18:52:10Z

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@linux.com>
>> ---
>>   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