shpc: standard hot plug controller

This adds support for SHPC interface, as defined by PCI Standard
Hot-Plug Controller and Subsystem Specification, Rev 1.0
http://www.pcisig.com/specifications/conventional/pci_hot_plug/SHPC_10

Only SHPC intergrated with a PCI-to-PCI bridge is supported,
SHPC integrated with a host bridge would need more work.

All main SHPC features are supported:
- MRL sensor
- Attention button
- Attention indicator
- Power indicator

Wake on hotplug and serr generation are stubbed out but unused
as we don't have interfaces to generate these events ATM.

One issue that isn't completely resolved is that qemu currently
expects an "eject" interface, which SHPC does not provide: it merely
removes the power to device and it's up to the user to remove the device
from slot. This patch works around that by ejecting the device
when power is removed and power LED goes off.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/hw/shpc.h b/hw/shpc.h
new file mode 100644
index 0000000000..130b71df30
--- /dev/null
+++ b/hw/shpc.h
@@ -0,0 +1,48 @@
+#ifndef SHPC_H
+#define SHPC_H
+
+#include "qemu-common.h"
+#include "memory.h"
+#include "vmstate.h"
+
+struct SHPCDevice {
+    /* Capability offset in device's config space */
+    int cap;
+
+    /* # of hot-pluggable slots */
+    int nslots;
+
+    /* SHPC WRS: working register set */
+    uint8_t *config;
+
+    /* Used to enable checks on load. Note that writable bits are
+     * never checked even if set in cmask. */
+    uint8_t *cmask;
+
+    /* Used to implement R/W bytes */
+    uint8_t *wmask;
+
+    /* Used to implement RW1C(Write 1 to Clear) bytes */
+    uint8_t *w1cmask;
+
+    /* MMIO for the SHPC BAR */
+    MemoryRegion mmio;
+
+    /* Bus controlled by this SHPC */
+    PCIBus *sec_bus;
+
+    /* MSI already requested for this event */
+    int msi_requested;
+};
+
+void shpc_reset(PCIDevice *d);
+int shpc_bar_size(PCIDevice *dev);
+int shpc_init(PCIDevice *dev, PCIBus *sec_bus, MemoryRegion *bar, unsigned off);
+void shpc_cleanup(PCIDevice *dev, MemoryRegion *bar);
+void shpc_cap_write_config(PCIDevice *d, uint32_t addr, uint32_t val, int len);
+
+extern VMStateInfo shpc_vmstate_info;
+#define SHPC_VMSTATE(_field, _type) \
+    VMSTATE_BUFFER_UNSAFE_INFO(_field, _type, 0, shpc_vmstate_info, 0)
+
+#endif