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Subject[PATCH] x86: usb debug port early console v4
Date

based on work from Eric, and add some timeout so don't dead loop when debug
device is not installed

v2: fix checkpatch warning
v3: move ehci struct def to linux/usrb/ehci_def.h from host/ehci.h
also add CONFIG_EARLY_PRINTK_DBGP to disable it by default
v4: address comments from Ingo, seperate ehci reg def moving to another patch
also add auto detect port that connect to debug device for Nvidia southbridge

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>

---
Documentation/kernel-parameters.txt | 3
arch/x86/Kconfig.debug | 13
arch/x86/kernel/early_printk.c | 764 +++++++++++++++++++++++++++++++++++-
3 files changed, 776 insertions(+), 4 deletions(-)

Index: linux-2.6/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6.orig/Documentation/kernel-parameters.txt
+++ linux-2.6/Documentation/kernel-parameters.txt
@@ -654,11 +654,12 @@ and is between 256 and 4096 characters.
earlyprintk= [X86-32,X86-64,SH,BLACKFIN]
earlyprintk=vga
earlyprintk=serial[,ttySn[,baudrate]]
+ earlyprintk=dbgp

Append ",keep" to not disable it when the real console
takes over.

- Only vga or serial at a time, not both.
+ Only vga or serial or usb debug port at a time.

Currently only ttyS0 and ttyS1 are supported.

Index: linux-2.6/arch/x86/kernel/early_printk.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/early_printk.c
+++ linux-2.6/arch/x86/kernel/early_printk.c
@@ -3,11 +3,19 @@
#include <linux/init.h>
#include <linux/string.h>
#include <linux/screen_info.h>
+#include <linux/usb/ch9.h>
+#include <linux/pci_regs.h>
+#include <linux/pci_ids.h>
+#include <linux/errno.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/fcntl.h>
#include <asm/setup.h>
#include <xen/hvc-console.h>
+#include <asm/pci-direct.h>
+#include <asm/pgtable.h>
+#include <asm/fixmap.h>
+#include <linux/usb/ehci_def.h>

/* Simple VGA output */
#define VGABASE (__ISA_IO_base + 0xb8000)
@@ -78,6 +86,7 @@ static int early_serial_base = 0x3f8; /
static int early_serial_putc(unsigned char ch)
{
unsigned timeout = 0xffff;
+
while ((inb(early_serial_base + LSR) & XMTRDY) == 0 && --timeout)
cpu_relax();
outb(ch, early_serial_base + TXR);
@@ -151,6 +160,721 @@ static struct console early_serial_conso
.index = -1,
};

+#ifdef CONFIG_EARLY_PRINTK_DBGP
+
+static struct ehci_caps __iomem *ehci_caps;
+static struct ehci_regs __iomem *ehci_regs;
+static struct ehci_dbg_port __iomem *ehci_debug;
+static unsigned int dbgp_endpoint_out;
+
+struct ehci_dev {
+ u32 bus;
+ u32 slot;
+ u32 func;
+};
+
+static struct ehci_dev ehci_dev;
+
+#define USB_DEBUG_DEVNUM 127
+
+#define DBGP_DATA_TOGGLE 0x8800
+
+static inline u32 dbgp_pid_update(u32 x, u32 tok)
+{
+ return ((x ^ DBGP_DATA_TOGGLE) & 0xffff00) | (tok & 0xff);
+}
+
+static inline u32 dbgp_len_update(u32 x, u32 len)
+{
+ return (x & ~0x0f) | (len & 0x0f);
+}
+
+/*
+ * USB Packet IDs (PIDs)
+ */
+
+/* token */
+#define USB_PID_OUT 0xe1
+#define USB_PID_IN 0x69
+#define USB_PID_SOF 0xa5
+#define USB_PID_SETUP 0x2d
+/* handshake */
+#define USB_PID_ACK 0xd2
+#define USB_PID_NAK 0x5a
+#define USB_PID_STALL 0x1e
+#define USB_PID_NYET 0x96
+/* data */
+#define USB_PID_DATA0 0xc3
+#define USB_PID_DATA1 0x4b
+#define USB_PID_DATA2 0x87
+#define USB_PID_MDATA 0x0f
+/* Special */
+#define USB_PID_PREAMBLE 0x3c
+#define USB_PID_ERR 0x3c
+#define USB_PID_SPLIT 0x78
+#define USB_PID_PING 0xb4
+#define USB_PID_UNDEF_0 0xf0
+
+#define USB_PID_DATA_TOGGLE 0x88
+#define DBGP_CLAIM (DBGP_OWNER | DBGP_ENABLED | DBGP_INUSE)
+
+#define PCI_CAP_ID_EHCI_DEBUG 0xa
+
+#define HUB_ROOT_RESET_TIME 50 /* times are in msec */
+#define HUB_SHORT_RESET_TIME 10
+#define HUB_LONG_RESET_TIME 200
+#define HUB_RESET_TIMEOUT 500
+
+#define DBGP_MAX_PACKET 8
+
+static int dbgp_wait_until_complete(void)
+{
+ u32 ctrl;
+ int loop = 0x100000;
+
+ do {
+ ctrl = readl(&ehci_debug->control);
+ /* Stop when the transaction is finished */
+ if (ctrl & DBGP_DONE)
+ break;
+ } while (--loop > 0);
+
+ if (!loop)
+ return -1;
+
+ /*
+ * Now that we have observed the completed transaction,
+ * clear the done bit.
+ */
+ writel(ctrl | DBGP_DONE, &ehci_debug->control);
+ return (ctrl & DBGP_ERROR) ? -DBGP_ERRCODE(ctrl) : DBGP_LEN(ctrl);
+}
+
+static void dbgp_mdelay(int ms)
+{
+ int i;
+
+ while (ms--) {
+ for (i = 0; i < 1000; i++)
+ outb(0x1, 0x80);
+ }
+}
+
+static void dbgp_breath(void)
+{
+ /* Sleep to give the debug port a chance to breathe */
+}
+
+static int dbgp_wait_until_done(unsigned ctrl)
+{
+ u32 pids, lpid;
+ int ret;
+ int loop = 3;
+
+retry:
+ writel(ctrl | DBGP_GO, &ehci_debug->control);
+ ret = dbgp_wait_until_complete();
+ pids = readl(&ehci_debug->pids);
+ lpid = DBGP_PID_GET(pids);
+
+ if (ret < 0)
+ return ret;
+
+ /*
+ * If the port is getting full or it has dropped data
+ * start pacing ourselves, not necessary but it's friendly.
+ */
+ if ((lpid == USB_PID_NAK) || (lpid == USB_PID_NYET))
+ dbgp_breath();
+
+ /* If I get a NACK reissue the transmission */
+ if (lpid == USB_PID_NAK) {
+ if (--loop > 0)
+ goto retry;
+ }
+
+ return ret;
+}
+
+static void dbgp_set_data(const void *buf, int size)
+{
+ const unsigned char *bytes = buf;
+ u32 lo, hi;
+ int i;
+
+ lo = hi = 0;
+ for (i = 0; i < 4 && i < size; i++)
+ lo |= bytes[i] << (8*i);
+ for (; i < 8 && i < size; i++)
+ hi |= bytes[i] << (8*(i - 4));
+ writel(lo, &ehci_debug->data03);
+ writel(hi, &ehci_debug->data47);
+}
+
+static void dbgp_get_data(void *buf, int size)
+{
+ unsigned char *bytes = buf;
+ u32 lo, hi;
+ int i;
+
+ lo = readl(&ehci_debug->data03);
+ hi = readl(&ehci_debug->data47);
+ for (i = 0; i < 4 && i < size; i++)
+ bytes[i] = (lo >> (8*i)) & 0xff;
+ for (; i < 8 && i < size; i++)
+ bytes[i] = (hi >> (8*(i - 4))) & 0xff;
+}
+
+static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,
+ const char *bytes, int size)
+{
+ u32 pids, addr, ctrl;
+ int ret;
+
+ if (size > DBGP_MAX_PACKET)
+ return -1;
+
+ addr = DBGP_EPADDR(devnum, endpoint);
+
+ pids = readl(&ehci_debug->pids);
+ pids = dbgp_pid_update(pids, USB_PID_OUT);
+
+ ctrl = readl(&ehci_debug->control);
+ ctrl = dbgp_len_update(ctrl, size);
+ ctrl |= DBGP_OUT;
+ ctrl |= DBGP_GO;
+
+ dbgp_set_data(bytes, size);
+ writel(addr, &ehci_debug->address);
+ writel(pids, &ehci_debug->pids);
+
+ ret = dbgp_wait_until_done(ctrl);
+ if (ret < 0)
+ return ret;
+
+ return ret;
+}
+
+static int dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data,
+ int size)
+{
+ u32 pids, addr, ctrl;
+ int ret;
+
+ if (size > DBGP_MAX_PACKET)
+ return -1;
+
+ addr = DBGP_EPADDR(devnum, endpoint);
+
+ pids = readl(&ehci_debug->pids);
+ pids = dbgp_pid_update(pids, USB_PID_IN);
+
+ ctrl = readl(&ehci_debug->control);
+ ctrl = dbgp_len_update(ctrl, size);
+ ctrl &= ~DBGP_OUT;
+ ctrl |= DBGP_GO;
+
+ writel(addr, &ehci_debug->address);
+ writel(pids, &ehci_debug->pids);
+ ret = dbgp_wait_until_done(ctrl);
+ if (ret < 0)
+ return ret;
+
+ if (size > ret)
+ size = ret;
+ dbgp_get_data(data, size);
+ return ret;
+}
+
+static int dbgp_control_msg(unsigned devnum, int requesttype, int request,
+ int value, int index, void *data, int size)
+{
+ u32 pids, addr, ctrl;
+ struct usb_ctrlrequest req;
+ int read;
+ int ret;
+
+ read = (requesttype & USB_DIR_IN) != 0;
+ if (size > (read ? DBGP_MAX_PACKET:0))
+ return -1;
+
+ /* Compute the control message */
+ req.bRequestType = requesttype;
+ req.bRequest = request;
+ req.wValue = value;
+ req.wIndex = index;
+ req.wLength = size;
+
+ pids = DBGP_PID_SET(USB_PID_DATA0, USB_PID_SETUP);
+ addr = DBGP_EPADDR(devnum, 0);
+
+ ctrl = readl(&ehci_debug->control);
+ ctrl = dbgp_len_update(ctrl, sizeof(req));
+ ctrl |= DBGP_OUT;
+ ctrl |= DBGP_GO;
+
+ /* Send the setup message */
+ dbgp_set_data(&req, sizeof(req));
+ writel(addr, &ehci_debug->address);
+ writel(pids, &ehci_debug->pids);
+ ret = dbgp_wait_until_done(ctrl);
+ if (ret < 0)
+ return ret;
+
+ /* Read the result */
+ return dbgp_bulk_read(devnum, 0, data, size);
+}
+
+
+/* Find a PCI capability */
+static u32 __init find_cap(u32 num, u32 slot, u32 func, int cap)
+{
+ u8 pos;
+ int bytes;
+
+ if (!(read_pci_config_16(num, slot, func, PCI_STATUS) &
+ PCI_STATUS_CAP_LIST))
+ return 0;
+
+ pos = read_pci_config_byte(num, slot, func, PCI_CAPABILITY_LIST);
+ for (bytes = 0; bytes < 48 && pos >= 0x40; bytes++) {
+ u8 id;
+
+ pos &= ~3;
+ id = read_pci_config_byte(num, slot, func, pos+PCI_CAP_LIST_ID);
+ if (id == 0xff)
+ break;
+ if (id == cap)
+ return pos;
+
+ pos = read_pci_config_byte(num, slot, func,
+ pos+PCI_CAP_LIST_NEXT);
+ }
+ return 0;
+}
+
+static u32 __init __find_dbgp(u32 bus, u32 slot, u32 func)
+{
+ u32 class;
+
+ class = read_pci_config(bus, slot, func, PCI_CLASS_REVISION);
+ if ((class >> 8) != PCI_CLASS_SERIAL_USB_EHCI)
+ return 0;
+
+ return find_cap(bus, slot, func, PCI_CAP_ID_EHCI_DEBUG);
+}
+
+static u32 __init find_dbgp(int ehci_num, u32 *rbus, u32 *rslot, u32 *rfunc)
+{
+ u32 bus, slot, func;
+
+ for (bus = 0; bus < 256; bus++) {
+ for (slot = 0; slot < 32; slot++) {
+ for (func = 0; func < 8; func++) {
+ unsigned cap;
+
+ cap = __find_dbgp(bus, slot, func);
+
+ if (!cap)
+ continue;
+ if (ehci_num-- != 0)
+ continue;
+ *rbus = bus;
+ *rslot = slot;
+ *rfunc = func;
+ return cap;
+ }
+ }
+ }
+ return 0;
+}
+
+static int ehci_reset_port(int port)
+{
+ u32 portsc;
+ u32 delay_time, delay;
+ int loop;
+
+ /* Reset the usb debug port */
+ portsc = readl(&ehci_regs->port_status[port - 1]);
+ portsc &= ~PORT_PE;
+ portsc |= PORT_RESET;
+ writel(portsc, &ehci_regs->port_status[port - 1]);
+
+ delay = HUB_ROOT_RESET_TIME;
+ for (delay_time = 0; delay_time < HUB_RESET_TIMEOUT;
+ delay_time += delay) {
+ dbgp_mdelay(delay);
+
+ portsc = readl(&ehci_regs->port_status[port - 1]);
+ if (portsc & PORT_RESET) {
+ /* force reset to complete */
+ loop = 2;
+ writel(portsc & ~(PORT_RWC_BITS | PORT_RESET),
+ &ehci_regs->port_status[port - 1]);
+ do {
+ portsc = readl(&ehci_regs->port_status[port-1]);
+ } while ((portsc & PORT_RESET) && (--loop > 0));
+ }
+
+ /* Device went away? */
+ if (!(portsc & PORT_CONNECT))
+ return -ENOTCONN;
+
+ /* bomb out completely if something weird happend */
+ if ((portsc & PORT_CSC))
+ return -EINVAL;
+
+ /* If we've finished resetting, then break out of the loop */
+ if (!(portsc & PORT_RESET) && (portsc & PORT_PE))
+ return 0;
+ }
+ return -EBUSY;
+}
+
+static int ehci_wait_for_port(int port)
+{
+ u32 status;
+ int ret, reps;
+
+ for (reps = 0; reps < 3; reps++) {
+ dbgp_mdelay(100);
+ status = readl(&ehci_regs->status);
+ if (status & STS_PCD) {
+ ret = ehci_reset_port(port);
+ if (ret == 0)
+ return 0;
+ }
+ }
+ return -ENOTCONN;
+}
+
+#ifdef DBGP_DEBUG
+# define dbgp_printk early_printk
+#else
+static inline void dbgp_printk(const char *fmt, ...) { }
+#endif
+
+typedef void (*set_debug_port_t)(int port);
+
+static void default_set_debug_port(int port)
+{
+}
+
+static set_debug_port_t set_debug_port = default_set_debug_port;
+
+static void nvidia_set_debug_port(int port)
+{
+ u32 dword;
+ dword = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
+ 0x74);
+ dword &= ~(0x0f<<12);
+ dword |= ((port & 0x0f)<<12);
+ write_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func, 0x74,
+ dword);
+ dbgp_printk("set debug port to %d\n", port);
+}
+
+static void __init detect_set_debug_port(void)
+{
+ u32 vendorid;
+
+ vendorid = read_pci_config(ehci_dev.bus, ehci_dev.slot, ehci_dev.func,
+ 0x00);
+
+ if ((vendorid & 0xffff) == 0x10de) {
+ dbgp_printk("using nvidia set_debug_port\n");
+ set_debug_port = nvidia_set_debug_port;
+ }
+}
+
+static int __init ehci_setup(void)
+{
+ struct usb_debug_descriptor dbgp_desc;
+ u32 cmd, ctrl, status, portsc, hcs_params;
+ u32 debug_port, new_debug_port = 0, n_ports;
+ u32 devnum;
+ int ret, i;
+ int loop;
+ int port_map_tried;
+ int playtimes = 3;
+
+try_next_time:
+ port_map_tried = 0;
+
+try_next_port:
+
+ hcs_params = readl(&ehci_caps->hcs_params);
+ debug_port = HCS_DEBUG_PORT(hcs_params);
+ n_ports = HCS_N_PORTS(hcs_params);
+
+ dbgp_printk("debug_port: %d\n", debug_port);
+ dbgp_printk("n_ports: %d\n", n_ports);
+
+ for (i = 1; i <= n_ports; i++) {
+ portsc = readl(&ehci_regs->port_status[i-1]);
+ dbgp_printk("portstatus%d: %08x\n", i, portsc);
+ }
+
+ if (port_map_tried && (new_debug_port != debug_port)) {
+ if (--playtimes) {
+ set_debug_port(new_debug_port);
+ goto try_next_time;
+ }
+ return -1;
+ }
+
+ loop = 10;
+ /* Reset the EHCI controller */
+ cmd = readl(&ehci_regs->command);
+ cmd |= CMD_RESET;
+ writel(cmd, &ehci_regs->command);
+ do {
+ cmd = readl(&ehci_regs->command);
+ } while ((cmd & CMD_RESET) && (--loop > 0));
+
+ if (!loop) {
+ dbgp_printk("can not reset ehci\n");
+ return -1;
+ }
+ dbgp_printk("ehci reset done\n");
+
+ /* Claim ownership, but do not enable yet */
+ ctrl = readl(&ehci_debug->control);
+ ctrl |= DBGP_OWNER;
+ ctrl &= ~(DBGP_ENABLED | DBGP_INUSE);
+ writel(ctrl, &ehci_debug->control);
+
+ /* Start the ehci running */
+ cmd = readl(&ehci_regs->command);
+ cmd &= ~(CMD_LRESET | CMD_IAAD | CMD_PSE | CMD_ASE | CMD_RESET);
+ cmd |= CMD_RUN;
+ writel(cmd, &ehci_regs->command);
+
+ /* Ensure everything is routed to the EHCI */
+ writel(FLAG_CF, &ehci_regs->configured_flag);
+
+ /* Wait until the controller is no longer halted */
+ loop = 10;
+ do {
+ status = readl(&ehci_regs->status);
+ } while ((status & STS_HALT) && (--loop > 0));
+
+ if (!loop) {
+ dbgp_printk("ehci can be started\n");
+ return -1;
+ }
+ dbgp_printk("ehci started\n");
+
+ /* Wait for a device to show up in the debug port */
+ ret = ehci_wait_for_port(debug_port);
+ if (ret < 0) {
+ dbgp_printk("No device found in debug port\n");
+ goto next_debug_port;
+ }
+ dbgp_printk("ehci wait for port done\n");
+
+ /* Enable the debug port */
+ ctrl = readl(&ehci_debug->control);
+ ctrl |= DBGP_CLAIM;
+ writel(ctrl, &ehci_debug->control);
+ ctrl = readl(&ehci_debug->control);
+ if ((ctrl & DBGP_CLAIM) != DBGP_CLAIM) {
+ dbgp_printk("No device in debug port\n");
+ writel(ctrl & ~DBGP_CLAIM, &ehci_debug->control);
+ goto err;
+ }
+ dbgp_printk("debug ported enabled\n");
+
+ /* Completely transfer the debug device to the debug controller */
+ portsc = readl(&ehci_regs->port_status[debug_port - 1]);
+ portsc &= ~PORT_PE;
+ writel(portsc, &ehci_regs->port_status[debug_port - 1]);
+
+ dbgp_mdelay(100);
+
+ /* Find the debug device and make it device number 127 */
+ for (devnum = 0; devnum <= 127; devnum++) {
+ ret = dbgp_control_msg(devnum,
+ USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+ USB_REQ_GET_DESCRIPTOR, (USB_DT_DEBUG << 8), 0,
+ &dbgp_desc, sizeof(dbgp_desc));
+ if (ret > 0)
+ break;
+ }
+ if (devnum > 127) {
+ dbgp_printk("Could not find attached debug device\n");
+ goto err;
+ }
+ if (ret < 0) {
+ dbgp_printk("Attached device is not a debug device\n");
+ goto err;
+ }
+ dbgp_endpoint_out = dbgp_desc.bDebugOutEndpoint;
+
+ /* Move the device to 127 if it isn't already there */
+ if (devnum != USB_DEBUG_DEVNUM) {
+ ret = dbgp_control_msg(devnum,
+ USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+ USB_REQ_SET_ADDRESS, USB_DEBUG_DEVNUM, 0, NULL, 0);
+ if (ret < 0) {
+ dbgp_printk("Could not move attached device to %d\n",
+ USB_DEBUG_DEVNUM);
+ goto err;
+ }
+ devnum = USB_DEBUG_DEVNUM;
+ dbgp_printk("debug device renamed to 127\n");
+ }
+
+ /* Enable the debug interface */
+ ret = dbgp_control_msg(USB_DEBUG_DEVNUM,
+ USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
+ USB_REQ_SET_FEATURE, USB_DEVICE_DEBUG_MODE, 0, NULL, 0);
+ if (ret < 0) {
+ dbgp_printk(" Could not enable the debug device\n");
+ goto err;
+ }
+ dbgp_printk("debug interface enabled\n");
+
+ /* Perform a small write to get the even/odd data state in sync
+ */
+ ret = dbgp_bulk_write(USB_DEBUG_DEVNUM, dbgp_endpoint_out, " ", 1);
+ if (ret < 0) {
+ dbgp_printk("dbgp_bulk_write failed: %d\n", ret);
+ goto err;
+ }
+ dbgp_printk("small write doned\n");
+
+ return 0;
+err:
+ /* Things didn't work so remove my claim */
+ ctrl = readl(&ehci_debug->control);
+ ctrl &= ~(DBGP_CLAIM | DBGP_OUT);
+ writel(ctrl, &ehci_debug->control);
+ return -1;
+
+next_debug_port:
+ port_map_tried |= (1<<(debug_port - 1));
+ new_debug_port = ((debug_port-1+1)%n_ports) + 1;
+ if (port_map_tried != ((1<<n_ports) - 1)) {
+ set_debug_port(new_debug_port);
+ goto try_next_port;
+ }
+ if (--playtimes) {
+ set_debug_port(new_debug_port);
+ goto try_next_time;
+ }
+
+ return -1;
+}
+
+static int __init early_dbgp_init(char *s)
+{
+ u32 debug_port, bar, offset;
+ u32 bus, slot, func, cap;
+ void __iomem *ehci_bar;
+ u32 dbgp_num;
+ u32 bar_val;
+ char *e;
+ int ret;
+ u8 byte;
+
+ if (!early_pci_allowed())
+ return -1;
+
+ dbgp_num = 0;
+ if (*s)
+ dbgp_num = simple_strtoul(s, &e, 10);
+ dbgp_printk("dbgp_num: %d\n", dbgp_num);
+
+ cap = find_dbgp(dbgp_num, &bus, &slot, &func);
+ if (!cap)
+ return -1;
+
+ dbgp_printk("Found EHCI debug port on %02x:%02x.%1x\n", bus, slot,
+ func);
+
+ debug_port = read_pci_config(bus, slot, func, cap);
+ bar = (debug_port >> 29) & 0x7;
+ bar = (bar * 4) + 0xc;
+ offset = (debug_port >> 16) & 0xfff;
+ dbgp_printk("bar: %02x offset: %03x\n", bar, offset);
+ if (bar != PCI_BASE_ADDRESS_0) {
+ dbgp_printk("only debug ports on bar 1 handled.\n");
+
+ return -1;
+ }
+
+ bar_val = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
+ dbgp_printk("bar_val: %02x offset: %03x\n", bar_val, offset);
+ if (bar_val & ~PCI_BASE_ADDRESS_MEM_MASK) {
+ dbgp_printk("only simple 32bit mmio bars supported\n");
+
+ return -1;
+ }
+
+ /* double check if the mem space is enabled */
+ byte = read_pci_config_byte(bus, slot, func, 0x04);
+ if (!(byte & 0x2)) {
+ byte |= 0x02;
+ write_pci_config_byte(bus, slot, func, 0x04, byte);
+ dbgp_printk("mmio for ehci enabled\n");
+ }
+
+ /*
+ * FIXME I don't have the bar size so just guess PAGE_SIZE is more
+ * than enough. 1K is the biggest I have seen.
+ */
+ set_fixmap_nocache(FIX_DBGP_BASE, bar_val & PAGE_MASK);
+ ehci_bar = (void __iomem *)__fix_to_virt(FIX_DBGP_BASE);
+ ehci_bar += bar_val & ~PAGE_MASK;
+ dbgp_printk("ehci_bar: %p\n", ehci_bar);
+
+ ehci_caps = ehci_bar;
+ ehci_regs = ehci_bar + HC_LENGTH(readl(&ehci_caps->hc_capbase));
+ ehci_debug = ehci_bar + offset;
+ ehci_dev.bus = bus;
+ ehci_dev.slot = slot;
+ ehci_dev.func = func;
+
+ detect_set_debug_port();
+
+ ret = ehci_setup();
+ if (ret < 0) {
+ dbgp_printk("ehci_setup failed\n");
+ ehci_debug = 0;
+
+ return -1;
+ }
+
+ return 0;
+}
+
+static void early_dbgp_write(struct console *con, const char *str, u32 n)
+{
+ int chunk, ret;
+
+ if (!ehci_debug)
+ return;
+ while (n > 0) {
+ chunk = n;
+ if (chunk > DBGP_MAX_PACKET)
+ chunk = DBGP_MAX_PACKET;
+ ret = dbgp_bulk_write(USB_DEBUG_DEVNUM,
+ dbgp_endpoint_out, str, chunk);
+ str += chunk;
+ n -= chunk;
+ }
+}
+
+static struct console early_dbgp_console = {
+ .name = "earlydbg",
+ .write = early_dbgp_write,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+};
+#endif
+
/* Console interface to a host file on AMD's SimNow! */

static int simnow_fd;
@@ -165,6 +889,7 @@ enum {
static noinline long simnow(long cmd, long a, long b, long c)
{
long ret;
+
asm volatile("cpuid" :
"=a" (ret) :
"b" (a), "c" (b), "d" (c), "0" (MAGIC1), "D" (cmd + MAGIC2));
@@ -174,6 +899,7 @@ static noinline long simnow(long cmd, lo
static void __init simnow_init(char *str)
{
char *fn = "klog";
+
if (*str == '=')
fn = ++str;
/* error ignored */
@@ -208,10 +934,11 @@ asmlinkage void early_printk(const char
va_end(ap);
}

-static int __initdata keep_early;

static int __init setup_early_printk(char *buf)
{
+ int keep_early;
+
if (!buf)
return 0;

@@ -219,8 +946,7 @@ static int __init setup_early_printk(cha
return 0;
early_console_initialized = 1;

- if (strstr(buf, "keep"))
- keep_early = 1;
+ keep_early = (strstr(buf, "keep") != NULL);

if (!strncmp(buf, "serial", 6)) {
early_serial_init(buf + 6);
@@ -238,6 +964,17 @@ static int __init setup_early_printk(cha
simnow_init(buf + 6);
early_console = &simnow_console;
keep_early = 1;
+#ifdef CONFIG_EARLY_PRINTK_DBGP
+ } else if (!strncmp(buf, "dbgp", 4)) {
+ if (early_dbgp_init(buf+4) < 0)
+ return 0;
+ early_console = &early_dbgp_console;
+ /*
+ * usb subsys will reset ehci controller, so don't keep
+ * that early console
+ */
+ keep_early = 0;
+#endif
#ifdef CONFIG_HVC_XEN
} else if (!strncmp(buf, "xen", 3)) {
early_console = &xenboot_console;
@@ -251,4 +988,23 @@ static int __init setup_early_printk(cha
register_console(early_console);
return 0;
}
+
+void __init enable_debug_console(char *buf)
+{
+#ifdef DBGP_DEBUG
+ struct console *old_early_console = NULL;
+
+ if (early_console_initialized && early_console) {
+ old_early_console = early_console;
+ unregister_console(early_console);
+ early_console_initialized = 0;
+ }
+
+ setup_early_printk(buf);
+
+ if (early_console == old_early_console && old_early_console)
+ register_console(old_early_console);
+#endif
+}
+
early_param("earlyprintk", setup_early_printk);
Index: linux-2.6/arch/x86/Kconfig.debug
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig.debug
+++ linux-2.6/arch/x86/Kconfig.debug
@@ -43,6 +43,19 @@ config EARLY_PRINTK
with klogd/syslogd or the X server. You should normally N here,
unless you want to debug such a crash.

+config EARLY_PRINTK_DBGP
+ bool "Early printk via EHCI debug port"
+ default n
+ depends on EARLY_PRINTK
+ 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,
+ unless you want to debug such a crash. You need usb debug device.
+
config DEBUG_STACKOVERFLOW
bool "Check for stack overflows"
depends on DEBUG_KERNEL

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