Files
linux/drivers/usb/host/xhci-dbgcap.h
Mathias Nyman 31620fc1c8 xhci: dbc: support runtime suspend while DbC is in enabled state
Allow xHC to runtime suspend if DbC is in 'enabled' state for over
15 seconds without a connect.

Idea is that every time we go to 'enabled' state we make sure DbC runtime
pm usage is '1' and save a timestamp. if the event loop still finds DbC in
enabled state 15 seconds later then it decrease DbC runtime pm usage by
calling pm_runtime_put().
Enabled state is reached either when DbC is enabled by userspace or a
connected/configured DbC is disconnected.

When a connect is detected we make sure DbC usage count is 1.

If DbC has been in 'enabled' state for 15 seconds and DbC usage is
decreased to 0 by pm_runtime_put, then the whole xHC controller may
runtime suspends to PCI D3 state if no other devices are using it

DbC sysfs file will show 'suspended' when xHC is suspended and will wake up
and enable DbC at cable connect, or when user writes 'enable' to the file.

This patch was originally part of a larger DbC series, but dropped before
the series was submitted to 7.2-rc1. The series has a locking issue in
commit 520058b73b ("xhci: dbc: serialize enabling and disabling dbc")
which is also resolved by this patch

Fixes: 520058b73b ("xhci: dbc: serialize enabling and disabling dbc")
Reported-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Closes: https://lore.kernel.org/linux-usb/9ce24ff5-efab-4089-92d7-709862d68e6d@intel.com
Tested-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260616100916.2234205-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-25 15:10:08 +01:00

279 lines
7.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/**
* xhci-dbgcap.h - xHCI debug capability support
*
* Copyright (C) 2017 Intel Corporation
*
* Author: Lu Baolu <baolu.lu@linux.intel.com>
*/
#ifndef __LINUX_XHCI_DBGCAP_H
#define __LINUX_XHCI_DBGCAP_H
#include <linux/tty.h>
#include <linux/kfifo.h>
struct dbc_regs {
__le32 capability;
__le32 doorbell;
__le32 ersts; /* Event Ring Segment Table Size*/
__le32 __reserved_0; /* 0c~0f reserved bits */
__le64 erstba; /* Event Ring Segment Table Base Address */
__le64 erdp; /* Event Ring Dequeue Pointer */
__le32 control;
__le32 status;
__le32 portsc; /* Port status and control */
__le32 __reserved_1; /* 2b~28 reserved bits */
__le64 dccp; /* Debug Capability Context Pointer */
__le32 devinfo1; /* Device Descriptor Info Register 1 */
__le32 devinfo2; /* Device Descriptor Info Register 2 */
};
struct dbc_info_context {
__le64 string0;
__le64 manufacturer;
__le64 product;
__le64 serial;
__le32 length;
__le32 __reserved_0[7];
};
#define DBC_CTRL_DBC_RUN BIT(0)
#define DBC_CTRL_PORT_ENABLE BIT(1)
#define DBC_CTRL_HALT_OUT_TR BIT(2)
#define DBC_CTRL_HALT_IN_TR BIT(3)
#define DBC_CTRL_DBC_RUN_CHANGE BIT(4)
#define DBC_CTRL_DBC_ENABLE BIT(31)
#define DBC_CTRL_MAXBURST(p) (((p) >> 16) & 0xff)
#define DBC_DOOR_BELL_TARGET(p) (((p) & 0xff) << 8)
#define DBC_MAX_PACKET 1024
#define DBC_CONTEXT_SIZE 64
/*
* Port status:
*/
#define DBC_PORTSC_CONN_STATUS BIT(0)
#define DBC_PORTSC_PORT_ENABLED BIT(1)
#define DBC_PORTSC_CONN_CHANGE BIT(17)
#define DBC_PORTSC_RESET_CHANGE BIT(21)
#define DBC_PORTSC_LINK_CHANGE BIT(22)
#define DBC_PORTSC_CONFIG_CHANGE BIT(23)
/*
* The maximum length of a string descriptor is 255, because the bLength
* field in the usb_string_descriptor struct is __u8. In practice the
* maximum length is 254, because a string descriptor consists of a 2 byte
* header followed by UTF-16 characters (2 bytes each). This allows for
* only 126 characters (code points) in the string, which is where
* USB_MAX_STRING_LEN comes from.
*/
#define USB_MAX_STRING_DESC_LEN 254
struct dbc_str_descs {
char string0[USB_MAX_STRING_DESC_LEN];
char manufacturer[USB_MAX_STRING_DESC_LEN];
char product[USB_MAX_STRING_DESC_LEN];
char serial[USB_MAX_STRING_DESC_LEN];
};
/*
* NULL terminated UTF-8 strings used to create UTF-16 strings
* (with maxiumum USB_MAX_STRING_LEN 2 byte characters).
*/
struct dbc_str {
char manufacturer[USB_MAX_STRING_LEN+1];
char product[USB_MAX_STRING_LEN+1];
char serial[USB_MAX_STRING_LEN+1];
};
#define DBC_PROTOCOL 1 /* GNU Remote Debug Command */
#define DBC_VENDOR_ID 0x1d6b /* Linux Foundation 0x1d6b */
#define DBC_PRODUCT_ID 0x0010 /* device 0010 */
#define DBC_DEVICE_REV 0x0010 /* 0.10 */
enum dbc_state {
DS_DISABLED = 0,
DS_INITIALIZED,
DS_ENABLED,
DS_CONNECTED,
DS_CONFIGURED,
DS_MAX
};
struct dbc_ep {
struct xhci_dbc *dbc;
struct list_head list_pending;
struct xhci_ring *ring;
unsigned int direction:1;
unsigned int halted:1;
};
#define DBC_QUEUE_SIZE 16
#define DBC_WRITE_BUF_SIZE 8192
#define DBC_POLL_INTERVAL_DEFAULT 64 /* milliseconds */
#define DBC_POLL_INTERVAL_MAX 5000 /* milliseconds */
#define DBC_XFER_INACTIVITY_TIMEOUT 10 /* milliseconds */
#define DBC_ENUMERATION_TIMEOUT 2000 /* milliseconds */
#define DBC_AUTOSUSPEND_DELAY 15000 /* milliseconds */
/*
* Private structure for DbC hardware state:
*/
struct dbc_port {
struct tty_port port;
spinlock_t port_lock; /* port access */
int minor;
struct list_head read_pool;
struct list_head read_queue;
unsigned int n_read;
struct tasklet_struct push;
struct list_head write_pool;
unsigned int tx_boundary;
bool registered;
bool tx_running;
};
struct dbc_driver {
int (*configure)(struct xhci_dbc *dbc);
void (*disconnect)(struct xhci_dbc *dbc);
};
struct xhci_dbc {
spinlock_t lock; /* device access */
struct mutex enable_mutex;
struct device *dev;
struct xhci_hcd *xhci;
struct dbc_regs __iomem *regs;
struct xhci_ring *ring_evt;
struct xhci_ring *ring_in;
struct xhci_ring *ring_out;
struct xhci_erst erst;
struct xhci_container_ctx *ctx;
struct dbc_str_descs *str_descs;
dma_addr_t str_descs_dma;
size_t str_descs_size;
struct dbc_str str;
u16 idVendor;
u16 idProduct;
u16 bcdDevice;
u8 bInterfaceProtocol;
enum dbc_state state;
struct delayed_work event_work;
unsigned int poll_interval; /* ms */
unsigned long xfer_timestamp;
unsigned long state_timestamp;
unsigned resume_required:1;
unsigned pending_rpm_put:1;
struct dbc_ep eps[2];
const struct dbc_driver *driver;
void *priv;
};
struct dbc_request {
void *buf;
unsigned int length;
dma_addr_t dma;
void (*complete)(struct xhci_dbc *dbc,
struct dbc_request *req);
struct list_head list_pool;
int status;
unsigned int actual;
struct xhci_dbc *dbc;
struct list_head list_pending;
dma_addr_t trb_dma;
union xhci_trb *trb;
unsigned direction:1;
};
#define dbc_bulkout_ctx(d) \
((struct xhci_ep_ctx *)((d)->ctx->bytes + DBC_CONTEXT_SIZE))
#define dbc_bulkin_ctx(d) \
((struct xhci_ep_ctx *)((d)->ctx->bytes + DBC_CONTEXT_SIZE * 2))
#define dbc_bulkout_enq(d) \
xhci_trb_virt_to_dma((d)->ring_out->enq_seg, (d)->ring_out->enqueue)
#define dbc_bulkin_enq(d) \
xhci_trb_virt_to_dma((d)->ring_in->enq_seg, (d)->ring_in->enqueue)
#define dbc_epctx_info2(t, p, b) \
cpu_to_le32(EP_TYPE(t) | MAX_PACKET(p) | MAX_BURST(b))
#define dbc_ep_dma_direction(d) \
((d)->direction ? DMA_FROM_DEVICE : DMA_TO_DEVICE)
#define BULK_OUT 0
#define BULK_IN 1
#define EPID_OUT 2
#define EPID_IN 3
enum evtreturn {
EVT_ERR = -1,
EVT_DONE,
EVT_XFER_DONE,
EVT_GSER,
EVT_DISC,
};
static inline struct dbc_ep *get_in_ep(struct xhci_dbc *dbc)
{
return &dbc->eps[BULK_IN];
}
static inline struct dbc_ep *get_out_ep(struct xhci_dbc *dbc)
{
return &dbc->eps[BULK_OUT];
}
#ifdef CONFIG_USB_XHCI_DBGCAP
int xhci_create_dbc_dev(struct xhci_hcd *xhci);
void xhci_remove_dbc_dev(struct xhci_hcd *xhci);
int xhci_dbc_init(void);
void xhci_dbc_exit(void);
int dbc_tty_init(void);
void dbc_tty_exit(void);
int xhci_dbc_tty_probe(struct device *dev, void __iomem *res, struct xhci_hcd *xhci);
void xhci_dbc_tty_remove(struct xhci_dbc *dbc);
struct xhci_dbc *xhci_alloc_dbc(struct device *dev, void __iomem *res,
const struct dbc_driver *driver);
void xhci_dbc_remove(struct xhci_dbc *dbc);
struct dbc_request *dbc_alloc_request(struct xhci_dbc *dbc,
unsigned int direction,
gfp_t flags);
void dbc_free_request(struct dbc_request *req);
int dbc_ep_queue(struct dbc_request *req);
#ifdef CONFIG_PM
int xhci_dbc_suspend(struct xhci_hcd *xhci);
int xhci_dbc_resume(struct xhci_hcd *xhci);
#endif /* CONFIG_PM */
#else
static inline int xhci_create_dbc_dev(struct xhci_hcd *xhci)
{
return 0;
}
static inline void xhci_remove_dbc_dev(struct xhci_hcd *xhci)
{
}
static inline int xhci_dbc_init(void)
{
return 0;
}
static inline void xhci_dbc_exit(void)
{
}
static inline int xhci_dbc_suspend(struct xhci_hcd *xhci)
{
return 0;
}
static inline int xhci_dbc_resume(struct xhci_hcd *xhci)
{
return 0;
}
#endif /* CONFIG_USB_XHCI_DBGCAP */
#endif /* __LINUX_XHCI_DBGCAP_H */