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Subject[PATCH] vfio: platform: reset: add support for XHCI reset hook
Date
The VFIO reset hook is called every time a platform device is passed
to a guest or removed from a guest.

When the XHCI device is unbound from the host, the host driver
disables the XHCI clocks/phys/regulators so when the device is passed
to the guest it becomes dis-functional.

This initial implementation uses the VFIO reset hook to enable the
XHCI clocks/phys on behalf of the guest.

Ported from Marvell LSP code originally written by Yehuda Yitschak

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
drivers/vfio/platform/reset/Kconfig | 8 +++
drivers/vfio/platform/reset/Makefile | 2 +
.../vfio/platform/reset/vfio_platform_xhci.c | 60 +++++++++++++++++++
3 files changed, 70 insertions(+)
create mode 100644 drivers/vfio/platform/reset/vfio_platform_xhci.c

diff --git a/drivers/vfio/platform/reset/Kconfig b/drivers/vfio/platform/reset/Kconfig
index 392e3c09def0..14f620fd250d 100644
--- a/drivers/vfio/platform/reset/Kconfig
+++ b/drivers/vfio/platform/reset/Kconfig
@@ -22,3 +22,11 @@ config VFIO_PLATFORM_BCMFLEXRM_RESET
Enables the VFIO platform driver to handle reset for Broadcom FlexRM

If you don't know what to do here, say N.
+
+config VFIO_PLATFORM_XHCI_RESET
+ tristate "VFIO support for USB XHCI reset"
+ depends on VFIO_PLATFORM
+ help
+ Enables the VFIO platform driver to handle reset for USB XHCI
+
+ If you don't know what to do here, say N.
diff --git a/drivers/vfio/platform/reset/Makefile b/drivers/vfio/platform/reset/Makefile
index 7294c5ea122e..d84c4d3dc041 100644
--- a/drivers/vfio/platform/reset/Makefile
+++ b/drivers/vfio/platform/reset/Makefile
@@ -1,7 +1,9 @@
# SPDX-License-Identifier: GPL-2.0
vfio-platform-calxedaxgmac-y := vfio_platform_calxedaxgmac.o
vfio-platform-amdxgbe-y := vfio_platform_amdxgbe.o
+vfio-platform-xhci-y := vfio_platform_xhci.o

obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o
obj-$(CONFIG_VFIO_PLATFORM_AMDXGBE_RESET) += vfio-platform-amdxgbe.o
obj-$(CONFIG_VFIO_PLATFORM_BCMFLEXRM_RESET) += vfio_platform_bcmflexrm.o
+obj-$(CONFIG_VFIO_PLATFORM_XHCI_RESET) += vfio-platform-xhci.o
diff --git a/drivers/vfio/platform/reset/vfio_platform_xhci.c b/drivers/vfio/platform/reset/vfio_platform_xhci.c
new file mode 100644
index 000000000000..7b75a04402ee
--- /dev/null
+++ b/drivers/vfio/platform/reset/vfio_platform_xhci.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * VFIO platform driver specialized for XHCI reset
+ *
+ * Copyright 2016 Marvell Semiconductors, Inc.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/usb/phy.h>
+
+#include "../vfio_platform_private.h"
+
+#define MAX_XHCI_CLOCKS 4
+#define MAX_XHCI_PHYS 2
+
+int vfio_platform_xhci_reset(struct vfio_platform_device *vdev)
+{
+ struct device *dev = vdev->device;
+ struct device_node *np = dev->of_node;
+ struct usb_phy *usb_phy;
+ struct clk *clk;
+ int ret, i;
+
+ /*
+ * Compared to the native driver, no need to handle the
+ * deferred case, because the resources are already
+ * there
+ */
+ for (i = 0; i < MAX_XHCI_CLOCKS; i++) {
+ clk = of_clk_get(np, i);
+ if (!IS_ERR(clk)) {
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ return -ENODEV;
+ }
+ }
+
+ usb_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 0);
+ if (!IS_ERR(usb_phy)) {
+ ret = usb_phy_init(usb_phy);
+ if (ret)
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+module_vfio_reset_handler("generic-xhci", vfio_platform_xhci_reset);
+
+MODULE_AUTHOR("Yehuda Yitschak");
+MODULE_DESCRIPTION("Reset support for XHCI vfio platform device");
+MODULE_LICENSE("GPL");
--
2.20.1
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