iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

usb/early: Add driver for xhci debug capability

Browse Source 
XHCI debug capability (DbC) is an optional but standalone
functionality provided by an xHCI host controller. Software
learns this capability by walking through the extended
capability list of the host. XHCI specification describes
DbC in section 7.6.

This patch introduces the code to probe and initialize the
debug capability hardware during early boot. With hardware
initialized, the debug target (system on which this code is
running) will present a debug device through the debug port
(normally the first USB3 port). The debug device is fully
compliant with the USB framework and provides the equivalent
of a very high performance (USB3) full-duplex serial link
between the debug host and target. The DbC functionality is
independent of the xHCI host. There isn't any precondition
from the xHCI host side for the DbC to work.

One use for this feature is kernel debugging, for example
when your machine crashes very early before the regular
console code is initialized. Other uses include simpler,
lockless logging instead of a full-blown printk console
driver and klogd.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-usb@vger.kernel.org
Link: http://lkml.kernel.org/r/1490083293-3792-3-git-send-email-baolu.lu@linux.intel.com
[ Small fix to the Kconfig help text. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Lu Baolu 2017-03-21 16:01:30 +08:00 committed by Ingo Molnar
parent dd759d93f4
commit aeb9dd1de9
6 changed files with 1281 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
arch/x86/Kconfig.debug
View File

@ -5,6 +5,9 @@ config TRACE_IRQFLAGS_SUPPORT
source "lib/Kconfig.debug"
config EARLY_PRINTK_USB
bool
config X86_VERBOSE_BOOTUP
bool "Enable verbose x86 bootup info messages"
default y
@ -23,19 +26,20 @@ config EARLY_PRINTK
This is useful for kernel debugging when your machine crashes very
early before the console code is initialized. For normal operation
it is not recommended because it looks ugly and doesn't cooperate
with klogd/syslogd or the X server. You should normally N here,
with klogd/syslogd or the X server. You should normally say N here,
unless you want to debug such a crash.
config EARLY_PRINTK_DBGP
bool "Early printk via EHCI debug port"
depends on EARLY_PRINTK && PCI
select EARLY_PRINTK_USB
---help---
Write kernel log output directly into the EHCI debug port.
This is useful for kernel debugging when your machine crashes very
early before the console code is initialized. For normal operation
it is not recommended because it looks ugly and doesn't cooperate
with klogd/syslogd or the X server. You should normally N here,
with klogd/syslogd or the X server. You should normally say N here,
unless you want to debug such a crash. You need usb debug device.
config EARLY_PRINTK_EFI
@ -48,6 +52,25 @@ config EARLY_PRINTK_EFI
This is useful for kernel debugging when your machine crashes very
early before the console code is initialized.
config EARLY_PRINTK_USB_XDBC
bool "Early printk via the xHCI debug port"
depends on EARLY_PRINTK && PCI
select EARLY_PRINTK_USB
---help---
Write kernel log output directly into the xHCI debug port.
One use for this feature is kernel debugging, for example when your
machine crashes very early before the regular console code is
initialized. Other uses include simpler, lockless logging instead of
a full-blown printk console driver + klogd.
For normal production environments this is normally not recommended,
because it doesn't feed events into klogd/syslogd and doesn't try to
print anything on the screen.
You should normally say N here, unless you want to debug early
crashes or need a very simple printk logging facility.
config X86_PTDUMP_CORE
def_bool n

2
drivers/usb/Makefile
View File

@ -49,7 +49,7 @@ obj-$(CONFIG_USB_MICROTEK) += image/
obj-$(CONFIG_USB_SERIAL) += serial/
obj-$(CONFIG_USB) += misc/
obj-$(CONFIG_EARLY_PRINTK_DBGP) += early/
obj-$(CONFIG_EARLY_PRINTK_USB) += early/
obj-$(CONFIG_USB_ATM) += atm/
obj-$(CONFIG_USB_SPEEDTOUCH) += atm/

1
drivers/usb/early/Makefile
View File

@ -3,3 +3,4 @@
#
obj-$(CONFIG_EARLY_PRINTK_DBGP) += ehci-dbgp.o
obj-$(CONFIG_EARLY_PRINTK_USB_XDBC) += xhci-dbc.o

1014
drivers/usb/early/xhci-dbc.c Normal file
View File

File diff suppressed because it is too large Load Diff

211
drivers/usb/early/xhci-dbc.h Normal file
View File

@ -0,0 +1,211 @@
/*
* xhci-dbc.h - xHCI debug capability early driver
*
* Copyright (C) 2016 Intel Corporation
*
* Author: Lu Baolu <baolu.lu@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __LINUX_XHCI_DBC_H
#define __LINUX_XHCI_DBC_H
#include <linux/types.h>
#include <linux/usb/ch9.h>
/*
* xHCI Debug Capability Register interfaces:
*/
struct xdbc_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 */
};
#define DEBUG_MAX_BURST(p) (((p) >> 16) & 0xff)
#define CTRL_DBC_RUN BIT(0)
#define CTRL_PORT_ENABLE BIT(1)
#define CTRL_HALT_OUT_TR BIT(2)
#define CTRL_HALT_IN_TR BIT(3)
#define CTRL_DBC_RUN_CHANGE BIT(4)
#define CTRL_DBC_ENABLE BIT(31)
#define DCST_DEBUG_PORT(p) (((p) >> 24) & 0xff)
#define PORTSC_CONN_STATUS BIT(0)
#define PORTSC_CONN_CHANGE BIT(17)
#define PORTSC_RESET_CHANGE BIT(21)
#define PORTSC_LINK_CHANGE BIT(22)
#define PORTSC_CONFIG_CHANGE BIT(23)
/*
* xHCI Debug Capability data structures:
*/
struct xdbc_trb {
__le32 field[4];
};
struct xdbc_erst_entry {
__le64 seg_addr;
__le32 seg_size;
__le32 __reserved_0;
};
struct xdbc_info_context {
__le64 string0;
__le64 manufacturer;
__le64 product;
__le64 serial;
__le32 length;
__le32 __reserved_0[7];
};
struct xdbc_ep_context {
__le32 ep_info1;
__le32 ep_info2;
__le64 deq;
__le32 tx_info;
__le32 __reserved_0[11];
};
struct xdbc_context {
struct xdbc_info_context info;
struct xdbc_ep_context out;
struct xdbc_ep_context in;
};
#define XDBC_INFO_CONTEXT_SIZE 48
#define XDBC_MAX_STRING_LENGTH 64
#define XDBC_STRING_MANUFACTURER "Linux"
#define XDBC_STRING_PRODUCT "Remote GDB"
#define XDBC_STRING_SERIAL "0001"
struct xdbc_strings {
char string0[XDBC_MAX_STRING_LENGTH];
char manufacturer[XDBC_MAX_STRING_LENGTH];
char product[XDBC_MAX_STRING_LENGTH];
char serial[XDBC_MAX_STRING_LENGTH];
};
#define XDBC_PROTOCOL 1 /* GNU Remote Debug Command Set */
#define XDBC_VENDOR_ID 0x1d6b /* Linux Foundation 0x1d6b */
#define XDBC_PRODUCT_ID 0x0004 /* __le16 idProduct; device 0004 */
#define XDBC_DEVICE_REV 0x0010 /* 0.10 */
/*
* xHCI Debug Capability software state structures:
*/
struct xdbc_segment {
struct xdbc_trb *trbs;
dma_addr_t dma;
};
#define XDBC_TRBS_PER_SEGMENT 256
struct xdbc_ring {
struct xdbc_segment *segment;
struct xdbc_trb *enqueue;
struct xdbc_trb *dequeue;
u32 cycle_state;
};
#define XDBC_EPID_OUT 2
#define XDBC_EPID_IN 3
struct xdbc_state {
u16 vendor;
u16 device;
u32 bus;
u32 dev;
u32 func;
void __iomem *xhci_base;
u64 xhci_start;
size_t xhci_length;
int port_number;
/* DbC register base */
struct xdbc_regs __iomem *xdbc_reg;
/* DbC table page */
dma_addr_t table_dma;
void *table_base;
/* event ring segment table */
dma_addr_t erst_dma;
size_t erst_size;
void *erst_base;
/* event ring segments */
struct xdbc_ring evt_ring;
struct xdbc_segment evt_seg;
/* debug capability contexts */
dma_addr_t dbcc_dma;
size_t dbcc_size;
void *dbcc_base;
/* descriptor strings */
dma_addr_t string_dma;
size_t string_size;
void *string_base;
/* bulk OUT endpoint */
struct xdbc_ring out_ring;
struct xdbc_segment out_seg;
void *out_buf;
dma_addr_t out_dma;
/* bulk IN endpoint */
struct xdbc_ring in_ring;
struct xdbc_segment in_seg;
void *in_buf;
dma_addr_t in_dma;
u32 flags;
/* spinlock for early_xdbc_write() reentrancy */
raw_spinlock_t lock;
};
#define XDBC_PCI_MAX_BUSES 256
#define XDBC_PCI_MAX_DEVICES 32
#define XDBC_PCI_MAX_FUNCTION 8
#define XDBC_TABLE_ENTRY_SIZE 64
#define XDBC_ERST_ENTRY_NUM 1
#define XDBC_DBCC_ENTRY_NUM 3
#define XDBC_STRING_ENTRY_NUM 4
/* Bits definitions for xdbc_state.flags: */
#define XDBC_FLAGS_INITIALIZED BIT(0)
#define XDBC_FLAGS_IN_STALL BIT(1)
#define XDBC_FLAGS_OUT_STALL BIT(2)
#define XDBC_FLAGS_IN_PROCESS BIT(3)
#define XDBC_FLAGS_OUT_PROCESS BIT(4)
#define XDBC_FLAGS_CONFIGURED BIT(5)
#define XDBC_MAX_PACKET 1024
/* Door bell target: */
#define OUT_EP_DOORBELL 0
#define IN_EP_DOORBELL 1
#define DOOR_BELL_TARGET(p) (((p) & 0xff) << 8)
#define xdbc_read64(regs) xhci_read_64(NULL, (regs))
#define xdbc_write64(val, regs) xhci_write_64(NULL, (val), (regs))
#endif /* __LINUX_XHCI_DBC_H */

29
include/linux/usb/xhci-dbgp.h Normal file
View File

@ -0,0 +1,29 @@
/*
* Standalone xHCI debug capability driver
*
* Copyright (C) 2016 Intel Corporation
*
* Author: Lu Baolu <baolu.lu@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef __LINUX_XHCI_DBGP_H
#define __LINUX_XHCI_DBGP_H
#ifdef CONFIG_EARLY_PRINTK_USB_XDBC
int __init early_xdbc_parse_parameter(char *s);
int __init early_xdbc_setup_hardware(void);
void __init early_xdbc_register_console(void);
#else
static inline int __init early_xdbc_setup_hardware(void)
{
return -ENODEV;
}
static inline void __init early_xdbc_register_console(void)
{
}
#endif /* CONFIG_EARLY_PRINTK_USB_XDBC */
#endif /* __LINUX_XHCI_DBGP_H */