On Tue, Sep 13, 2016 at 10:31:59AM -0600, Keith Busch wrote:
> This patch adds a new flag to the pci_dev structure instructing pciehp
> to not interpret PCIe slot LED indicators. The pciehp driver will instead
> allow all LED control from the user by setting the slot control indicators
> as the user requested through sysfs. This is preparing for domain devices
> that repurpose these control bits for non-standard use.
>
> Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
I applied this with a few minor tweaks to pci/hotplug for v4.9, thanks!
The tweaks are:
- s/pciehp_set_raw_attention_status/pciehp_set_raw_indicator_status/ and
s/pciehp_get_raw_attention_status/pciehp_get_raw_indicator_status/
because we're now talking to *both* Attention and Power Indicators,
not just the Attention Indicator.
- s/user_leds/hotplug_user_indicators/ to use spec terminology
("indicator") and to put it in a "hotplug" group in pci_dev.
- Expand changelog to the following to highlight the fact that we're
adding user control of the Power Indicator, which didn't exist before:
PCI: pciehp: Allow exclusive userspace control of indicators
PCIe hotplug supports optional Attention and Power Indicators, which are
used internally by pciehp. Users can't control the Power Indicator, but
they can control the Attention Indicator by writing to a sysfs "attention"
file.
The Slot Control register has two bits for each indicator, and the PCIe
spec defines the encodings for each as (Reserved/On/Blinking/Off). For
sysfs "attention" writes, pciehp_set_attention_status() maps into these
encodings, so the only useful write values are 0 (Off), 1 (On), and 2
(Blinking).
However, some platforms use all four bits for platform-specific indicators,
and they need to allow direct user control of them while preventing pciehp
from using them at all.
Add a "hotplug_user_indicators" flag to the pci_dev structure. When set,
pciehp does not use either the Attention Indicator or the Power Indicator,
and the low four bits (values 0x0 - 0xf) of sysfs "attention" write values
are written directly to the Attention Indicator Control and Power Indicator
Control fields.
Let me know if any of these are problematic. Obviously I don't have a way
to test and make sure I didn't break something.
> ---
> v3 -> v4:
>
> Fixing symbol usage by generating patch from the tree that compiles
> correctly.
>
> drivers/pci/hotplug/pciehp.h | 5 +++++
> drivers/pci/hotplug/pciehp_core.c | 3 +++
> drivers/pci/hotplug/pciehp_hpc.c | 27 +++++++++++++++++++++++++++
> include/linux/pci.h | 1 +
> 4 files changed, 36 insertions(+)
>
> diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
> index e764918..725078d 100644
> --- a/drivers/pci/hotplug/pciehp.h
> +++ b/drivers/pci/hotplug/pciehp.h
> @@ -152,6 +152,11 @@ bool pciehp_check_link_active(struct controller *ctrl);
> void pciehp_release_ctrl(struct controller *ctrl);
> int pciehp_reset_slot(struct slot *slot, int probe);
>
> +int pciehp_set_raw_attention_status(struct hotplug_slot *hotplug_slot,
> + u8 status);
> +int pciehp_get_raw_attention_status(struct hotplug_slot *hotplug_slot,
> + u8 *status);
> +
> static inline const char *slot_name(struct slot *slot)
> {
> return hotplug_slot_name(slot->hotplug_slot);
> diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
> index fb0f863..68b7aeb 100644
> --- a/drivers/pci/hotplug/pciehp_core.c
> +++ b/drivers/pci/hotplug/pciehp_core.c
> @@ -113,6 +113,9 @@ static int init_slot(struct controller *ctrl)
> if (ATTN_LED(ctrl)) {
> ops->get_attention_status = get_attention_status;
> ops->set_attention_status = set_attention_status;
> + } else if (ctrl->pcie->port->user_leds) {
> + ops->get_attention_status = pciehp_get_raw_attention_status;
> + ops->set_attention_status = pciehp_set_raw_attention_status;
> }
>
> /* register this slot with the hotplug pci core */
> diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
> index 08e84d6..5ab8604 100644
> --- a/drivers/pci/hotplug/pciehp_hpc.c
> +++ b/drivers/pci/hotplug/pciehp_hpc.c
> @@ -355,6 +355,18 @@ static int pciehp_link_enable(struct controller *ctrl)
> return __pciehp_link_set(ctrl, true);
> }
>
> +int pciehp_get_raw_attention_status(struct hotplug_slot *hotplug_slot,
> + u8 *status)
> +{
> + struct slot *slot = hotplug_slot->private;
> + struct pci_dev *pdev = ctrl_dev(slot->ctrl);
> + u16 slot_ctrl;
> +
> + pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
> + *status = (slot_ctrl & (PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC)) >> 6;
> + return 0;
> +}
> +
> void pciehp_get_attention_status(struct slot *slot, u8 *status)
> {
> struct controller *ctrl = slot->ctrl;
> @@ -431,6 +443,17 @@ int pciehp_query_power_fault(struct slot *slot)
> return !!(slot_status & PCI_EXP_SLTSTA_PFD);
> }
>
> +int pciehp_set_raw_attention_status(struct hotplug_slot *hotplug_slot,
> + u8 status)
> +{
> + struct slot *slot = hotplug_slot->private;
> + struct controller *ctrl = slot->ctrl;
> +
> + pcie_write_cmd_nowait(ctrl, status << 6,
> + PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC);
> + return 0;
> +}
> +
> void pciehp_set_attention_status(struct slot *slot, u8 value)
> {
> struct controller *ctrl = slot->ctrl;
> @@ -804,6 +827,10 @@ struct controller *pcie_init(struct pcie_device *dev)
> }
> ctrl->pcie = dev;
> pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
> +
> + if (pdev->user_leds)
> + slot_cap &= ~(PCI_EXP_SLTCAP_AIP | PCI_EXP_SLTCAP_PIP);
> +
> ctrl->slot_cap = slot_cap;
> mutex_init(&ctrl->ctrl_lock);
> init_waitqueue_head(&ctrl->queue);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 7256f33..f41bbca 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -308,6 +308,7 @@ struct pci_dev {
> powered on/off by the
> corresponding bridge */
> unsigned int ignore_hotplug:1; /* Ignore hotplug events */
> + unsigned int user_leds:1; /* User excluse LED SlotCtl */
> unsigned int d3_delay; /* D3->D0 transition time in ms */
> unsigned int d3cold_delay; /* D3cold->D0 transition time in ms */
>
> --
> 2.7.2
>
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