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.

[bhelgaas: changelog, rename flag and accessors to s/attention/indicator/]
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index e764918641ae..37d70b5ad22f 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -152,6 +152,9 @@ 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_indicator_status(struct hotplug_slot *h_slot, u8 status);
+int pciehp_get_raw_indicator_status(struct hotplug_slot *h_slot, u8 *status);
+
 static inline const char *slot_name(struct slot *slot)
 {
 	return hotplug_slot_name(slot->hotplug_slot);