On Tue, Aug 20, 2019 at 2:07 AM Denis Efremov <efremov@xxxxxxxxx> wrote:
>
> Add pciehp_set_indicators() to set power and attention indicators with a
> single register write. Thus, avoiding waiting twice for Command Complete.
>
> Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
> ---
> drivers/pci/hotplug/pciehp.h | 1 +
> drivers/pci/hotplug/pciehp_hpc.c | 29 +++++++++++++++++++++++++++++
> include/uapi/linux/pci_regs.h | 2 ++
> 3 files changed, 32 insertions(+)
>
> diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
> index 8c51a04b8083..0e272bf3deb4 100644
> --- a/drivers/pci/hotplug/pciehp.h
> +++ b/drivers/pci/hotplug/pciehp.h
> @@ -167,6 +167,7 @@ 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, int pwr, int 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..5474b9854a7f 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -443,6 +443,35 @@ 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, int pwr, int attn)
> +{
> + u16 cmd = 0, mask = 0;
> +
> + if (PWR_LED(ctrl))
> + switch (pwr) {
> + case PCI_EXP_SLTCTL_PWR_IND_ON:
> + case PCI_EXP_SLTCTL_PWR_IND_BLINK:
> + case PCI_EXP_SLTCTL_PWR_IND_OFF:
Do you need an explicit /* fallthrough */ comment? I thought the
fallthrough warning was enabled by default now.
> + cmd |= pwr;
> + mask |= PCI_EXP_SLTCTL_PIC;
> + }
> +
> + if (ATTN_LED(ctrl))
> + switch (attn) {
> + case PCI_EXP_SLTCTL_ATTN_IND_ON:
> + case PCI_EXP_SLTCTL_ATTN_IND_BLINK:
> + case PCI_EXP_SLTCTL_ATTN_IND_OFF:
> + cmd |= attn;
> + mask |= PCI_EXP_SLTCTL_AIC;
> + }
> +
> + if (cmd) {
> + 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..291788b58f3a 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_NONE 0x0 /* Attention Indicator noop */
> #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_NONE 0x0 /* Power Indicator noop */
I don't think pci_regs.h is the right place for this. The contents of
pci_regs.h is essentially a transcription of bit definitions from the
various PCI standards documents. The PCIe Base spec says the the 0b00
combination for the two-bit Power and Attn indicator fields is
reserved and there's nothing suggesting that writing a zero to those
fields should preserve the current value. Basicly, we now have a
implementation quirk of pcie_set_indicators() masquerading as part of
the standard.
> #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 */
> --
> 2.21.0
>
