Re: [PATCH 1/1] 8250_kgdb driver reworked
From: Tom Rini
Date: Thu Sep 01 2005 - 18:37:51 EST
On Thu, Sep 01, 2005 at 03:45:09PM -0700, Tom Rini wrote:
[snip]
> So digging back in CVS it seems this was added to fix a spurious
> interrupt that occured on an (probably) an x86_64 box when NMI support
> didn't work correctly. I think it's safe enough to just drop this.
Since reposting seems to be getting more and more helpful feedback,
here's things again:
Index: linux-2.6.13/drivers/serial/8250.c
===================================================================
--- linux-2.6.13.orig/drivers/serial/8250.c
+++ linux-2.6.13/drivers/serial/8250.c
@@ -2516,6 +2516,27 @@ void serial8250_unregister_port(int line
}
EXPORT_SYMBOL(serial8250_unregister_port);
+/**
+ * serial8250_unregister_by_port - remove a 16x50 serial port
+ * at runtime.
+ * @port: A &struct uart_port that describes the port to remove.
+ *
+ * Remove one serial port. This may not be called from interrupt
+ * context. We hand the port back to the our control.
+ */
+void serial8250_unregister_by_port(struct uart_port *port)
+{
+ struct uart_8250_port *uart;
+
+ down(&serial_sem);
+ uart = serial8250_find_match_or_unused(port);
+ up(&serial_sem);
+
+ if (uart)
+ serial8250_unregister_port(uart->port.line);
+}
+EXPORT_SYMBOL(serial8250_unregister_by_port);
+
static int __init serial8250_init(void)
{
int ret, i;
Index: linux-2.6.13/drivers/serial/8250.h
===================================================================
--- linux-2.6.13.orig/drivers/serial/8250.h
+++ linux-2.6.13/drivers/serial/8250.h
@@ -19,6 +19,7 @@
int serial8250_register_port(struct uart_port *);
void serial8250_unregister_port(int line);
+void serial8250_unregister_by_port(struct uart_port *port);
void serial8250_suspend_port(int line);
void serial8250_resume_port(int line);
Index: linux-2.6.13/drivers/serial/Kconfig
===================================================================
--- linux-2.6.13.orig/drivers/serial/Kconfig
+++ linux-2.6.13/drivers/serial/Kconfig
@@ -87,7 +87,7 @@ config SERIAL_8250_ACPI
config SERIAL_8250_NR_UARTS
int "Maximum number of 8250/16550 serial ports"
- depends on SERIAL_8250
+ depends on SERIAL_8250 || KGDB_8250
default "4"
help
Set this to the number of serial ports you want the driver
Index: linux-2.6.13/drivers/serial/Makefile
===================================================================
--- linux-2.6.13.orig/drivers/serial/Makefile
+++ linux-2.6.13/drivers/serial/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_SERIAL_JSM) += jsm/
obj-$(CONFIG_SERIAL_TXX9) += serial_txx9.o
obj-$(CONFIG_SERIAL_VR41XX) += vr41xx_siu.o
obj-$(CONFIG_SERIAL_SGI_IOC4) += ioc4_serial.o
+obj-$(CONFIG_KGDB_8250) += 8250_kgdb.o
Index: linux-2.6.13/lib/Kconfig.debug
===================================================================
--- linux-2.6.13.orig/lib/Kconfig.debug
+++ linux-2.6.13/lib/Kconfig.debug
@@ -193,7 +193,7 @@ config KGDB_CONSOLE
choice
prompt "Method for KGDB communication"
depends on KGDB
- default KGDB_ONLY_MODULES
+ default KGDB_8250_NOMODULE
default KGDB_MPSC if SERIAL_MPSC
help
There are a number of different ways in which you can communicate
@@ -212,6 +212,14 @@ config KGDB_ONLY_MODULES
Use only kernel modules to configure KGDB I/O after the
kernel is booted.
+config KGDB_8250_NOMODULE
+ bool "KGDB: On generic serial port (8250)"
+ select KGDB_8250
+ help
+ Uses generic serial port (8250) to communicate with the host
+ GDB. This is independent of the normal (SERIAL_8250) driver
+ for this chipset.
+
config KGDB_MPSC
bool "KGDB on MV64x60 MPSC"
depends on SERIAL_MPSC
@@ -219,4 +227,54 @@ config KGDB_MPSC
Uses a Marvell GT64260B or MV64x60 Multi-Purpose Serial
Controller (MPSC) channel. Note that the GT64260A is not
supported.
+
endchoice
+
+config KGDB_8250
+ tristate "KGDB: On generic serial port (8250)" if !KGDB_8250_NOMODULE
+ depends on m && KGDB_ONLY_MODULES
+ help
+ Uses generic serial port (8250) to communicate with the host
+ GDB. This is independent of the normal (SERIAL_8250) driver
+ for this chipset.
+
+config KGDB_SIMPLE_SERIAL
+ bool "Simple selection of KGDB serial port"
+ depends on KGDB_8250
+ default y
+ help
+ If you say Y here, you will only have to pick the baud rate
+ and port number that you wish to use for KGDB. Note that this
+ only works on architectures that register known serial ports
+ early on. If you say N, you will have to provide, either here
+ or on the command line, the type (I/O or MMIO), IRQ and
+ address to use. If in doubt, say Y.
+
+config KGDB_BAUDRATE
+ int "Debug serial port baud rate"
+ depends on (KGDB_8250 && KGDB_SIMPLE_SERIAL)
+ default "115200"
+ help
+ gdb and the kernel stub need to agree on the baud rate to be
+ used. Standard rates from 9600 to 115200 are allowed, and this
+ may be overridden via the commandline.
+
+config KGDB_PORT_NUM
+ int "Serial port number for KGDB"
+ range 0 1 if KGDB_MPSC
+ range 0 3
+ depends on (KGDB_8250 && KGDB_SIMPLE_SERIAL) || KGDB_MPSC
+ default "1"
+ help
+ Pick the port number (0 based) for KGDB to use.
+
+config KGDB_8250_CONF_STRING
+ string "Configuration string for KGDB"
+ depends on KGDB_8250 && !KGDB_SIMPLE_SERIAL
+ default "io,2f8,115200,3" if X86
+ help
+ The format of this string should be <io or
+ mem>,<address>,<baud rate>,<irq>. For example, to use the
+ serial port on an i386 box located at 0x2f8 and 115200 baud
+ on IRQ 3 at use:
+ io,2f8,115200,3
Index: linux-2.6.13/drivers/serial/8250_kgdb.c
===================================================================
--- /dev/null
+++ linux-2.6.13/drivers/serial/8250_kgdb.c
@@ -0,0 +1,515 @@
+/*
+ * 8250 interface for kgdb.
+ *
+ * This is a merging of many different drivers, and all of the people have
+ * had an impact in some form or another:
+ *
+ * 2004-2005 (c) MontaVista Software, Inc.
+ * 2005 (c) Wind River Systems, Inc.
+ *
+ * Amit Kale <amitkale@xxxxxxxxxxxxx>, David Grothe <dave@xxxxxxxx>,
+ * Scott Foehner <sfoehner@xxxxxxxxxxxx>, George Anzinger <george@xxxxxxxxxx>,
+ * Robert Walsh <rjwalsh@xxxxxxxxxxxx>, wangdi <wangdi@xxxxxxxxxxxxx>,
+ * San Mehat, Tom Rini <trini@xxxxxxxxxx>,
+ * Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kgdb.h>
+#include <linux/interrupt.h>
+#include <linux/tty.h>
+#include <linux/serial.h>
+#include <linux/serial_reg.h>
+#include <linux/serialP.h>
+#include <linux/ioport.h>
+
+#include <asm/io.h>
+#include <asm/serial.h> /* For BASE_BAUD and SERIAL_PORT_DFNS */
+
+#include "8250.h"
+
+#define GDB_BUF_SIZE 512 /* power of 2, please */
+
+MODULE_DESCRIPTION("KGDB driver for the 8250");
+MODULE_LICENSE("GPL");
+/* These will conflict with early_param otherwise. */
+#ifdef CONFIG_KGDB_8250_MODULE
+static char config[256];
+module_param_string(kgdb8250, config, 256, 0);
+MODULE_PARM_DESC(kgdb8250,
+ " kgdb8250=<io or mem>,<address>,<baud rate>,<irq>\n");
+static struct kgdb_io local_kgdb_io_ops;
+#endif /* CONFIG_KGDB_8250_MODULE */
+
+/* Speed of the UART. */
+static int kgdb8250_baud;
+
+/* Flag for if we need to call request_mem_region */
+static int kgdb8250_needs_request_mem_region;
+
+static char kgdb8250_buf[GDB_BUF_SIZE];
+static atomic_t kgdb8250_buf_in_cnt;
+static int kgdb8250_buf_out_inx;
+
+/* Old-style serial definitions, if existant, and a counter. */
+#ifdef CONFIG_KGDB_SIMPLE_SERIAL
+static int __initdata should_copy_rs_table = 1;
+static struct serial_state old_rs_table[] __initdata = {
+#ifdef SERIAL_PORT_DFNS
+ SERIAL_PORT_DFNS
+#endif
+};
+#endif
+
+/* Our internal table of UARTS. */
+#define UART_NR CONFIG_SERIAL_8250_NR_UARTS
+static struct uart_port kgdb8250_ports[UART_NR];
+
+static struct uart_port *current_port;
+
+/* Base of the UART. */
+static void *kgdb8250_addr;
+
+/* Forward declarations. */
+static int kgdb8250_init(void);
+static int __init kgdb_init_io(void);
+static int __init kgdb8250_opt(char *str);
+
+/* These are much shorter calls to ioread8/iowrite8 that take into
+ * account our shifts, etc. */
+static inline unsigned int kgdb_ioread(u8 mask)
+{
+ return ioread8(kgdb8250_addr + (mask << current_port->regshift));
+}
+
+static inline void kgdb_iowrite(u8 val, u8 mask)
+{
+ iowrite8(val, kgdb8250_addr + (mask << current_port->regshift));
+}
+
+/*
+ * Wait until the interface can accept a char, then write it.
+ */
+static void kgdb_put_debug_char(u8 chr)
+{
+ while (!(kgdb_ioread(UART_LSR) & UART_LSR_THRE)) ;
+
+ kgdb_iowrite(chr, UART_TX);
+}
+
+/*
+ * Get a byte from the hardware data buffer and return it
+ */
+static int read_data_bfr(void)
+{
+ char it = kgdb_ioread(UART_LSR);
+
+ if (it & UART_LSR_DR)
+ return kgdb_ioread(UART_RX);
+
+ /*
+ * If we have a framing error assume somebody messed with
+ * our uart. Reprogram it and send '-' both ways...
+ */
+ if (it & 0xc) {
+ kgdb8250_init();
+ kgdb_put_debug_char('-');
+ return '-';
+ }
+
+ return -1;
+}
+
+/*
+ * Get a char if available, return -1 if nothing available.
+ * Empty the receive buffer first, then look at the interface hardware.
+ */
+static int kgdb_get_debug_char(void)
+{
+ int retchr;
+
+ /* intr routine has q'd chars */
+ if (atomic_read(&kgdb8250_buf_in_cnt) != 0) {
+ retchr = kgdb8250_buf[kgdb8250_buf_out_inx++];
+ kgdb8250_buf_out_inx &= (GDB_BUF_SIZE - 1);
+ atomic_dec(&kgdb8250_buf_in_cnt);
+ return retchr;
+ }
+
+ do {
+ retchr = read_data_bfr();
+ } while (retchr < 0);
+
+ return retchr;
+}
+
+/*
+ * This is the receiver interrupt routine for the GDB stub.
+ * All that we need to do is verify that the interrupt happened on the
+ * line we're in charge of. If this is true, schedule a breakpoint and
+ * return.
+ */
+static irqreturn_t
+kgdb8250_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+ if (kgdb_ioread(UART_IIR) & UART_IIR_RDI) {
+ /* Throw away the data if another I/O routine is active. */
+ if (kgdb_io_ops.read_char != kgdb_get_debug_char &&
+ (kgdb_ioread(UART_LSR) & UART_LSR_DR))
+ kgdb_ioread(UART_RX);
+ else
+ breakpoint();
+ }
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Returns:
+ * 0 on success, 1 on failure.
+ */
+static int kgdb8250_init(void)
+{
+ unsigned cval;
+ int cflag = CREAD | HUPCL | CLOCAL | CS8;
+ char ier = UART_IER_RDI;
+ unsigned int base_baud;
+
+ base_baud = current_port->uartclk ?
+ current_port->uartclk / 16 : BASE_BAUD;
+
+ /*
+ * Now construct a cflag setting.
+ */
+ switch (kgdb8250_baud) {
+ case 1200:
+ cflag |= B1200;
+ break;
+ case 2400:
+ cflag |= B2400;
+ break;
+ case 4800:
+ cflag |= B4800;
+ break;
+ case 19200:
+ cflag |= B19200;
+ break;
+ case 38400:
+ cflag |= B38400;
+ break;
+ case 57600:
+ cflag |= B57600;
+ break;
+ case 115200:
+ cflag |= B115200;
+ break;
+ default:
+ kgdb8250_baud = 9600;
+ /* Fall through */
+ case 9600:
+ cflag |= B9600;
+ break;
+ }
+
+ /*
+ * Divisor, bytesize and parity
+ *
+ */
+
+ cval = cflag & (CSIZE | CSTOPB);
+ cval >>= 4;
+
+ /* Disable UART interrupts, set DTR and RTS high and set speed. */
+#if defined(CONFIG_ARCH_OMAP1510)
+ /* Workaround to enable 115200 baud on OMAP1510 internal ports */
+ if (cpu_is_omap1510() && is_omap_port((void *)kgdb8250_addr)) {
+ if (kgdb8250_baud == 115200) {
+ base_baud = 1;
+ kgdb8250_baud = 1;
+ kgdb_iowrite(1, UART_OMAP_OSC_12M_SEL);
+ } else
+ kgdb_iowrite(0, UART_OMAP_OSC_12M_SEL);
+ }
+#endif
+ /* set DLAB */
+ kgdb_iowrite(cval | UART_LCR_DLAB, UART_LCR);
+ /* LS */
+ kgdb_iowrite(base_baud / kgdb8250_baud & 0xff, UART_DLL);
+ /* MS */
+ kgdb_iowrite(base_baud / kgdb8250_baud >> 8, UART_DLM);
+ /* reset DLAB */
+ kgdb_iowrite(cval, UART_LCR);
+
+ /*
+ * XScale-specific bits that need to be set
+ */
+ if (current_port->type == PORT_XSCALE)
+ ier |= UART_IER_UUE | UART_IER_RTOIE;
+
+ /* turn on interrupts */
+ kgdb_iowrite(ier, UART_IER);
+ kgdb_iowrite(UART_MCR_OUT2 | UART_MCR_DTR | UART_MCR_RTS, UART_MCR);
+
+ /*
+ * If we read 0xff from the LSR, there is no UART here.
+ */
+ if (kgdb_ioread(UART_LSR) == 0xff)
+ return -1;
+ return 0;
+}
+
+/*
+ * Copy the old serial_state table to our uart_port table if we haven't
+ * had values specifically configured in. We need to make sure this only
+ * happens once.
+ */
+static void __init kgdb8250_copy_rs_table(void)
+{
+#ifdef CONFIG_KGDB_SIMPLE_SERIAL
+ int i;
+
+ if (!should_copy_rs_table)
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(old_rs_table); i++) {
+ kgdb8250_ports[i].iobase = old_rs_table[i].port;
+ kgdb8250_ports[i].irq = irq_canonicalize(old_rs_table[i].irq);
+ kgdb8250_ports[i].uartclk = old_rs_table[i].baud_base * 16;
+ kgdb8250_ports[i].membase = old_rs_table[i].iomem_base;
+ kgdb8250_ports[i].iotype = old_rs_table[i].io_type;
+ kgdb8250_ports[i].regshift = old_rs_table[i].iomem_reg_shift;
+ kgdb8250_ports[i].line = i;
+ }
+
+ should_copy_rs_table = 0;
+#endif
+}
+
+/*
+ * Hookup our IRQ line now that it is safe to do so, after we grab any
+ * memory regions we might need to. If we haven't been initialized yet,
+ * go ahead and copy the old_rs_table in.
+ */
+static void __init kgdb8250_late_init(void)
+{
+ /* Try and copy the old_rs_table. */
+ kgdb8250_copy_rs_table();
+
+#if defined(CONFIG_SERIAL_8250) || defined (CONFIG_SERIAL_8250_MODULE)
+ /* Take the port away from the main driver. */
+ serial8250_unregister_by_port(current_port);
+
+ /* Now reinit the port as the above has disabled things. */
+ kgdb8250_init();
+#endif
+ /* We may need to call request_mem_region() first. */
+ if (kgdb8250_needs_request_mem_region)
+ request_mem_region(current_port->mapbase,
+ 8 << current_port->regshift, "kgdb");
+ if (request_irq(current_port->irq, kgdb8250_interrupt, SA_SHIRQ,
+ "GDB-stub", current_port) < 0)
+ printk(KERN_ERR "KGDB failed to request the serial IRQ (%d)\n",
+ current_port->irq);
+}
+
+static __init int kgdb_init_io(void)
+{
+ /* Give us the basic table of uarts. */
+ kgdb8250_copy_rs_table();
+
+#ifdef CONFIG_KGDB_8250_MODULE
+ if (strlen(config)) {
+ if (kgdb8250_opt(config))
+ return -EINVAL;
+ } else {
+ printk(KERN_ERR "kgdb8250: argument error, usage: "
+ "kgdb8250=<io or mem>,<address>,<baud rate>" ",<irq>\n");
+ return -EINVAL;
+ }
+#endif /* CONFIG_KGDB_8250_MODULE */
+#ifdef CONFIG_KGDB_SIMPLE_SERIAL
+ kgdb8250_baud = CONFIG_KGDB_BAUDRATE;
+
+ /* Setup our pointer to the serial port now. */
+ current_port = &kgdb8250_ports[CONFIG_KGDB_PORT_NUM];
+#else
+ if (kgdb8250_opt(CONFIG_KGDB_8250_CONF_STRING))
+ return -EINVAL;
+#endif
+
+
+ /* Internal driver setup. */
+ switch (current_port->iotype) {
+ case UPIO_MEM:
+ if (current_port->mapbase)
+ kgdb8250_needs_request_mem_region = 1;
+ if (current_port->flags & UPF_IOREMAP) {
+ current_port->membase = ioremap(current_port->mapbase,
+ 8 << current_port->regshift);
+ if (!current_port->membase)
+ return -EIO; /* Failed. */
+ }
+ kgdb8250_addr = current_port->membase;
+ break;
+ case UPIO_PORT:
+ default:
+ kgdb8250_addr = ioport_map(current_port->iobase,
+ 8 << current_port->regshift);
+ if (!kgdb8250_addr)
+ return -EIO; /* Failed. */
+ }
+
+ if (kgdb8250_init() == -1) {
+ printk(KERN_ERR "kgdb8250: init failed\n");
+ return -EIO;
+ }
+#ifdef CONFIG_KGDB_8250_MODULE
+ /* Attach the kgdb irq. When this is built into the kernel, it
+ * is called as a part of late_init sequence.
+ */
+ kgdb8250_late_init();
+ if (kgdb_register_io_module(&local_kgdb_io_ops))
+ return -EINVAL;
+
+ printk(KERN_INFO "kgdb8250: debugging enabled\n");
+#endif /* CONFIG_KGD_8250_MODULE */
+
+ return 0;
+}
+
+#ifdef CONFIG_KGDB_8250_MODULE
+/* If it is a module the kgdb_io_ops should be a static which
+ * is passed to the KGDB I/O initialization
+ */
+static struct kgdb_io local_kgdb_io_ops = {
+#else /* ! CONFIG_KGDB_8250_MODULE */
+struct kgdb_io kgdb_io_ops = {
+#endif /* ! CONFIG_KGD_8250_MODULE */
+ .read_char = kgdb_get_debug_char,
+ .write_char = kgdb_put_debug_char,
+ .init = kgdb_init_io,
+ .late_init = kgdb8250_late_init,
+};
+
+/**
+ * kgdb8250_add_port - Define a serial port for use with KGDB
+ * @i: The index of the port being added
+ * @serial_req: The &struct uart_port describing the port
+ *
+ * On platforms where we must register the serial device
+ * dynamically, this is the best option if a platform also normally
+ * calls early_serial_setup().
+ */
+void __init kgdb8250_add_port(int i, struct uart_port *serial_req)
+{
+ /* Make sure we've got the built-in data before we override. */
+ kgdb8250_copy_rs_table();
+
+ /* Copy the whole thing over. */
+ memcpy(&kgdb8250_ports[i], serial_req, sizeof(struct uart_port));
+}
+
+/**
+ * kgdb8250_add_platform_port - Define a serial port for use with KGDB
+ * @i: The index of the port being added
+ * @p: The &struct plat_serial8250_port describing the port
+ *
+ * On platforms where we must register the serial device
+ * dynamically, this is the best option if a platform normally
+ * handles uart setup with an array of &struct plat_serial8250_port.
+ */
+void __init kgdb8250_add_platform_port(int i, struct plat_serial8250_port *p)
+{
+ /* Make sure we've got the built-in data before we override. */
+ kgdb8250_copy_rs_table();
+
+ kgdb8250_ports[i].iobase = p->iobase;
+ kgdb8250_ports[i].membase = p->membase;
+ kgdb8250_ports[i].irq = p->irq;
+ kgdb8250_ports[i].uartclk = p->uartclk;
+ kgdb8250_ports[i].regshift = p->regshift;
+ kgdb8250_ports[i].iotype = p->iotype;
+ kgdb8250_ports[i].flags = p->flags;
+ kgdb8250_ports[i].mapbase = p->mapbase;
+}
+
+/*
+ * Syntax for this cmdline option is:
+ * kgdb8250=<io or mem>,<address>,<baud rate>,<irq>"
+ */
+static int __init kgdb8250_opt(char *str)
+{
+ /* We'll fill out and use the first slot. */
+ current_port = &kgdb8250_ports[0];
+
+ if (!strncmp(str, "io", 2)) {
+ current_port->iotype = UPIO_PORT;
+ str += 2;
+ } else if (!strncmp(str, "mmio", 4)) {
+ current_port->iotype = UPIO_MEM;
+ str += 4;
+ } else
+ goto errout;
+
+ if (*str != ',')
+ goto errout;
+ str++;
+
+ if (current_port->iotype == UPIO_PORT)
+ current_port->iobase = simple_strtoul(str, &str, 16);
+ else
+ current_port->membase =
+ (unsigned char *)simple_strtoul(str, &str, 16);
+
+ if (*str != ',')
+ goto errout;
+ str++;
+
+ kgdb8250_baud = simple_strtoul(str, &str, 10);
+ if (!kgdb8250_baud)
+ goto errout;
+
+ if (*str != ',')
+ goto errout;
+ str++;
+
+ current_port->irq = simple_strtoul(str, &str, 10);
+
+#ifdef CONFIG_KGDB_SIMPLE_SERIAL
+ should_copy_rs_table = 0;
+#endif
+
+ return 0;
+
+ errout:
+ printk(KERN_ERR "Invalid syntax for option kgdb8250=\n");
+ return 1;
+}
+
+#ifdef CONFIG_KGDB_8250_MODULE
+static void cleanup_kgdb8250(void)
+{
+ kgdb_unregister_io_module(&local_kgdb_io_ops);
+
+ /* Clean up the irq and memory */
+ free_irq(current_port->irq, current_port);
+
+ if (kgdb8250_needs_request_mem_region)
+ release_mem_region(current_port->mapbase,
+ 8 << current_port->regshift);
+ /* Hook up the serial port back to what it was previously
+ * hooked up to.
+ */
+#if defined(CONFIG_SERIAL_8250) || defined(CONFIG_SERIAL_8250_MODULE)
+ /* Give the port back to the 8250 driver. */
+ serial8250_register_port(current_port);
+#endif
+}
+
+module_init(kgdb_init_io);
+module_exit(cleanup_kgdb8250);
+#else /* ! CONFIG_KGDB_8250_MODULE */
+early_param("kgdb8250", kgdb8250_opt);
+#endif /* ! CONFIG_KGDB_8250_MODULE */
>
> --
> Tom Rini
> http://gate.crashing.org/~trini/
--
Tom Rini
http://gate.crashing.org/~trini/
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