PCI: pciehp: Retain Power Indicator bits for userspace indicators

The sysfs "attention" file normally controls the Slot Control Attention
Indicator with 0 (off), 1 (on), 2 (blink) settings.

576243b ("PCI: pciehp: Allow exclusive userspace control of
indicators") added pciehp_set_raw_indicator_status() to allow userspace to
directly control all four bits in both the Attention Indicator and the
Power Indicator fields via the "attention" file.

This is used on Intel VMD bridges so utilities like "ledmon" can use sysfs
"attention" to control up to 16 indicators for NVMe device RAID status.

abaaac4 ("PCI: hotplug: Use FIELD_GET/PREP()") broke this by masking
the sysfs data with PCI_EXP_SLTCTL_AIC, which discards the upper two bits
intended for the Power Indicator Control field (PCI_EXP_SLTCTL_PIC).

For NVMe devices behind an Intel VMD, ledmon settings that use the
PCI_EXP_SLTCTL_PIC bits, i.e., ATTENTION_REBUILD (0x5), ATTENTION_LOCATE
(0x7), ATTENTION_FAILURE (0xD), ATTENTION_OFF (0xF), no longer worked
correctly.

Mask with PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC to retain both the
Attention Indicator and the Power Indicator bits.

Fixes: abaaac4 ("PCI: hotplug: Use FIELD_GET/PREP()")
Link: https://lore.kernel.org/r/20240722141440.7210-1-blazej.kucman@intel.com
Signed-off-by: Blazej Kucman <blazej.kucman@intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org	# v6.7+

drivers/pci/hotplug/pciehp_hpc.c

@@ -485,7 +485,9 @@ int pciehp_set_raw_indicator_status(struct hotplug_slot *hotplug_slot,
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 
 	pci_config_pm_runtime_get(pdev);
-	pcie_write_cmd_nowait(ctrl, FIELD_PREP(PCI_EXP_SLTCTL_AIC, status),
+
+	/* Attention and Power Indicator Control bits are supported */
+	pcie_write_cmd_nowait(ctrl, FIELD_PREP(PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC, status),
 			      PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC);
 	pci_config_pm_runtime_put(pdev);
 	return 0;