[usb] Expose USB device descriptor and strings via settings
Allow scripts to read basic information from USB device descriptors
via the settings mechanism. For example:
echo USB vendor ID: ${usb/${busloc}.8.2}
echo USB device ID: ${usb/${busloc}.10.2}
echo USB manufacturer name: ${usb/${busloc}.14.0}
The general syntax is
usb/<bus:dev>.<offset>.<length>
where bus:dev is the USB bus:device address (as obtained via the
"usbscan" command, or from e.g. ${net0/busloc} for a USB network
device), and <offset> and <length> select the required portion of the
USB device descriptor.
Following the usage of SMBIOS settings tags, a <length> of zero may be
used to indicate that the byte at <offset> contains a USB string
descriptor index, and an <offset> of zero may be used to indicate that
the <length> contains a literal USB string descriptor index.
Since the byte at offset zero can never contain a string index, and a
literal string index can never be zero, the combination of both
<length> and <offset> being zero may be used to indicate that the
entire device descriptor is to be read as a raw hex dump.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
diff --git a/src/config/config_usb.c b/src/config/config_usb.c
index b679aeb..10dec22 100644
--- a/src/config/config_usb.c
+++ b/src/config/config_usb.c
@@ -22,6 +22,7 @@
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <config/usb.h>
+#include <config/settings.h>
/** @file
*
@@ -63,3 +64,10 @@
#ifdef USB_EFI
REQUIRE_OBJECT ( efi_usb );
#endif
+
+/*
+ * Drag in USB settings mechanism
+ */
+#ifdef USB_SETTINGS
+REQUIRE_OBJECT ( usb_settings );
+#endif
diff --git a/src/config/settings.h b/src/config/settings.h
index d7f787d..7b4af4f 100644
--- a/src/config/settings.h
+++ b/src/config/settings.h
@@ -12,6 +12,7 @@
#include <config/defaults.h>
#define PCI_SETTINGS /* PCI device settings */
+#define USB_SETTINGS /* USB device settings */
//#define CPUID_SETTINGS /* CPUID settings */
//#define MEMMAP_SETTINGS /* Memory map settings */
//#define VMWARE_SETTINGS /* VMware GuestInfo settings */
diff --git a/src/drivers/bus/usb.c b/src/drivers/bus/usb.c
index e1e7d51..b3b361b 100644
--- a/src/drivers/bus/usb.c
+++ b/src/drivers/bus/usb.c
@@ -914,10 +914,9 @@
*/
int usb_get_string_descriptor ( struct usb_device *usb, unsigned int index,
unsigned int language, char *buf, size_t len ) {
- size_t max = ( len ? ( len - 1 /* NUL */ ) : 0 );
struct {
struct usb_descriptor_header header;
- uint16_t character[max];
+ uint16_t character[len];
} __attribute__ (( packed )) *desc;
unsigned int actual;
unsigned int i;
@@ -952,10 +951,9 @@
sizeof ( desc->character[0] ) );
/* Copy to buffer */
- for ( i = 0 ; ( ( i < actual ) && ( i < max ) ) ; i++ )
+ memset ( buf, 0, len );
+ for ( i = 0 ; ( ( i < actual ) && ( i < len ) ) ; i++ )
buf[i] = le16_to_cpu ( desc->character[i] );
- if ( len )
- buf[i] = '\0';
/* Free buffer */
free ( desc );
diff --git a/src/drivers/bus/usb_settings.c b/src/drivers/bus/usb_settings.c
new file mode 100644
index 0000000..db6f94d
--- /dev/null
+++ b/src/drivers/bus/usb_settings.c
@@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdio.h>
+#include <errno.h>
+#include <ipxe/usb.h>
+#include <ipxe/settings.h>
+#include <ipxe/init.h>
+
+/** @file
+ *
+ * USB device settings
+ *
+ */
+
+/** USB device settings scope */
+static const struct settings_scope usb_settings_scope;
+
+/**
+ * Check applicability of USB device setting
+ *
+ * @v settings Settings block
+ * @v setting Setting
+ * @ret applies Setting applies within this settings block
+ */
+static int usb_settings_applies ( struct settings *settings __unused,
+ const struct setting *setting ) {
+
+ return ( setting->scope == &usb_settings_scope );
+}
+
+/**
+ * Fetch value of USB device setting
+ *
+ * @v settings Settings block
+ * @v setting Setting to fetch
+ * @v data Buffer to fill with setting data
+ * @v len Length of buffer
+ * @ret len Length of setting data, or negative error
+ */
+static int usb_settings_fetch ( struct settings *settings __unused,
+ struct setting *setting,
+ void *data, size_t len ) {
+ uint8_t *dst = data;
+ const uint8_t *src;
+ const uint8_t *desc;
+ struct usb_bus *bus;
+ struct usb_device *usb;
+ int tag_direction;
+ unsigned int tag_busdev;
+ unsigned int tag_offset;
+ unsigned int tag_len;
+ unsigned int index;
+ int rc;
+
+ /* Extract parameters from tag */
+ tag_direction = ( ( setting->tag & ( 1 << 31 ) ) ? +1 : -1 );
+ tag_busdev = ( ( setting->tag >> 16 ) & 0x7fff );
+ tag_offset = ( ( setting->tag >> 8 ) & 0xff );
+ tag_len = ( ( setting->tag >> 0 ) & 0xff );
+
+ /* Locate USB device */
+ bus = find_usb_bus ( USB_BUS ( tag_busdev ) );
+ if ( ! bus )
+ return -ENODEV;
+ usb = find_usb ( bus, USB_DEV ( tag_busdev ) );
+ if ( ! usb )
+ return -ENODEV;
+ desc = ( ( const uint8_t * ) &usb->device );
+
+ /* Following the usage of SMBIOS settings tags, a <length> of
+ * zero indicates that the byte at <offset> contains a string
+ * index. An <offset> of zero indicates that the <length>
+ * contains a literal string index.
+ *
+ * Since the byte at offset zero can never contain a string
+ * index, and a literal string index can never be zero, the
+ * combination of both <length> and <offset> being zero
+ * indicates that the entire structure is to be read.
+ *
+ * By default we reverse the byte direction since USB values
+ * are little-endian and iPXE settings are big-endian. We
+ * invert this default when reading the entire structure.
+ */
+ if ( ( tag_len == 0 ) && ( tag_offset == 0 ) ) {
+ tag_len = sizeof ( usb->device );
+ tag_direction = -tag_direction;
+ } else if ( ( tag_len == 0 ) || ( tag_offset == 0 ) ) {
+ index = tag_len;
+ if ( ( ! index ) && ( tag_offset < sizeof ( usb->device ) ) )
+ index = desc[tag_offset];
+ if ( ( rc = usb_get_string_descriptor ( usb, index, 0, data,
+ len ) ) < 0 ) {
+ return rc;
+ }
+ if ( ! setting->type )
+ setting->type = &setting_type_string;
+ return rc;
+ }
+
+ /* Limit length */
+ if ( tag_offset > sizeof ( usb->device ) ) {
+ tag_len = 0;
+ } else if ( ( tag_offset + tag_len ) > sizeof ( usb->device ) ) {
+ tag_len = ( sizeof ( usb->device ) - tag_offset );
+ }
+
+ /* Copy data, reversing endianness if applicable */
+ dst = data;
+ src = ( desc + tag_offset );
+ if ( tag_direction < 0 )
+ src += ( tag_len - 1 );
+ if ( len > tag_len )
+ len = tag_len;
+ for ( ; len-- ; src += tag_direction, dst++ )
+ *dst = *src;
+
+ /* Set type to ":hexraw" if not already specified */
+ if ( ! setting->type )
+ setting->type = &setting_type_hexraw;
+
+ return tag_len;
+}
+
+/** USB device settings operations */
+static struct settings_operations usb_settings_operations = {
+ .applies = usb_settings_applies,
+ .fetch = usb_settings_fetch,
+};
+
+/** USB device settings */
+static struct settings usb_settings = {
+ .refcnt = NULL,
+ .siblings = LIST_HEAD_INIT ( usb_settings.siblings ),
+ .children = LIST_HEAD_INIT ( usb_settings.children ),
+ .op = &usb_settings_operations,
+ .default_scope = &usb_settings_scope,
+};
+
+/** Initialise USB device settings */
+static void usb_settings_init ( void ) {
+ int rc;
+
+ if ( ( rc = register_settings ( &usb_settings, NULL, "usb" ) ) != 0 ) {
+ DBG ( "USB could not register settings: %s\n",
+ strerror ( rc ) );
+ return;
+ }
+}
+
+/** USB device settings initialiser */
+struct init_fn usb_settings_init_fn __init_fn ( INIT_NORMAL ) = {
+ .initialise = usb_settings_init,
+};
diff --git a/src/drivers/net/ecm.c b/src/drivers/net/ecm.c
index ab1f983..7b3e92b 100644
--- a/src/drivers/net/ecm.c
+++ b/src/drivers/net/ecm.c
@@ -97,8 +97,9 @@
int rc;
/* Fetch MAC address string */
+ buf[ sizeof ( buf ) - 1 ] = '\0';
len = usb_get_string_descriptor ( usb, desc->mac, 0, buf,
- sizeof ( buf ) );
+ ( sizeof ( buf ) - 1 ) );
if ( len < 0 ) {
rc = len;
return rc;
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 01a2be6..6183e5b 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -424,6 +424,7 @@
#define ERRFILE_widget_ui ( ERRFILE_OTHER | 0x00620000 )
#define ERRFILE_form_ui ( ERRFILE_OTHER | 0x00630000 )
#define ERRFILE_usb_cmd ( ERRFILE_OTHER | 0x00640000 )
+#define ERRFILE_usb_settings ( ERRFILE_OTHER | 0x00650000 )
/** @} */
