Revision 810198bc9c109489dfadc57131c5183ce6ad2d7d authored by Rajashekhara, Sudhakar on 12 July 2011, 10:28:53 UTC, committed by Sekhar Nori on 07 September 2011, 08:53:01 UTC
DA850/OMAP-L138 EMAC driver uses random mac address instead of a fixed one because the mac address is not stuffed into EMAC platform data. This patch provides a function which reads the mac address stored in SPI flash (registered as MTD device) and populates the EMAC platform data. The function which reads the mac address is registered as a callback which gets called upon addition of MTD device. NOTE: In case the MAC address stored in SPI flash is erased, follow the instructions at [1] to restore it. [1] http://processors.wiki.ti.com/index.php/GSG:_OMAP-L138_DVEVM_Additional_Procedures#Restoring_MAC_address_on_SPI_Flash Modifications in v2: Guarded registering the mtd_notifier only when MTD is enabled. Earlier this was handled using mtd_has_partitions() call, but this has been removed in Linux v3.0. Modifications in v3: a. Guarded da850_evm_m25p80_notify_add() function and da850evm_spi_notifier structure with CONFIG_MTD macros. b. Renamed da850_evm_register_mtd_user() function to da850_evm_setup_mac_addr() and removed the struct mtd_notifier argument to this function. c. Passed the da850evm_spi_notifier structure to register_mtd_user() function. Modifications in v4: Moved the da850_evm_setup_mac_addr() function within the first CONFIG_MTD ifdef construct. Signed-off-by: Rajashekhara, Sudhakar <sudhakar.raj@ti.com> Signed-off-by: Sekhar Nori <nsekhar@ti.com> Cc: stable@kernel.org
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sysfs-pci.txt
Accessing PCI device resources through sysfs
--------------------------------------------
sysfs, usually mounted at /sys, provides access to PCI resources on platforms
that support it. For example, a given bus might look like this:
/sys/devices/pci0000:17
|-- 0000:17:00.0
| |-- class
| |-- config
| |-- device
| |-- enable
| |-- irq
| |-- local_cpus
| |-- remove
| |-- resource
| |-- resource0
| |-- resource1
| |-- resource2
| |-- rom
| |-- subsystem_device
| |-- subsystem_vendor
| `-- vendor
`-- ...
The topmost element describes the PCI domain and bus number. In this case,
the domain number is 0000 and the bus number is 17 (both values are in hex).
This bus contains a single function device in slot 0. The domain and bus
numbers are reproduced for convenience. Under the device directory are several
files, each with their own function.
file function
---- --------
class PCI class (ascii, ro)
config PCI config space (binary, rw)
device PCI device (ascii, ro)
enable Whether the device is enabled (ascii, rw)
irq IRQ number (ascii, ro)
local_cpus nearby CPU mask (cpumask, ro)
remove remove device from kernel's list (ascii, wo)
resource PCI resource host addresses (ascii, ro)
resource0..N PCI resource N, if present (binary, mmap, rw[1])
resource0_wc..N_wc PCI WC map resource N, if prefetchable (binary, mmap)
rom PCI ROM resource, if present (binary, ro)
subsystem_device PCI subsystem device (ascii, ro)
subsystem_vendor PCI subsystem vendor (ascii, ro)
vendor PCI vendor (ascii, ro)
ro - read only file
rw - file is readable and writable
wo - write only file
mmap - file is mmapable
ascii - file contains ascii text
binary - file contains binary data
cpumask - file contains a cpumask type
[1] rw for RESOURCE_IO (I/O port) regions only
The read only files are informational, writes to them will be ignored, with
the exception of the 'rom' file. Writable files can be used to perform
actions on the device (e.g. changing config space, detaching a device).
mmapable files are available via an mmap of the file at offset 0 and can be
used to do actual device programming from userspace. Note that some platforms
don't support mmapping of certain resources, so be sure to check the return
value from any attempted mmap. The most notable of these are I/O port
resources, which also provide read/write access.
The 'enable' file provides a counter that indicates how many times the device
has been enabled. If the 'enable' file currently returns '4', and a '1' is
echoed into it, it will then return '5'. Echoing a '0' into it will decrease
the count. Even when it returns to 0, though, some of the initialisation
may not be reversed.
The 'rom' file is special in that it provides read-only access to the device's
ROM file, if available. It's disabled by default, however, so applications
should write the string "1" to the file to enable it before attempting a read
call, and disable it following the access by writing "0" to the file. Note
that the device must be enabled for a rom read to return data successfully.
In the event a driver is not bound to the device, it can be enabled using the
'enable' file, documented above.
The 'remove' file is used to remove the PCI device, by writing a non-zero
integer to the file. This does not involve any kind of hot-plug functionality,
e.g. powering off the device. The device is removed from the kernel's list of
PCI devices, the sysfs directory for it is removed, and the device will be
removed from any drivers attached to it. Removal of PCI root buses is
disallowed.
Accessing legacy resources through sysfs
----------------------------------------
Legacy I/O port and ISA memory resources are also provided in sysfs if the
underlying platform supports them. They're located in the PCI class hierarchy,
e.g.
/sys/class/pci_bus/0000:17/
|-- bridge -> ../../../devices/pci0000:17
|-- cpuaffinity
|-- legacy_io
`-- legacy_mem
The legacy_io file is a read/write file that can be used by applications to
do legacy port I/O. The application should open the file, seek to the desired
port (e.g. 0x3e8) and do a read or a write of 1, 2 or 4 bytes. The legacy_mem
file should be mmapped with an offset corresponding to the memory offset
desired, e.g. 0xa0000 for the VGA frame buffer. The application can then
simply dereference the returned pointer (after checking for errors of course)
to access legacy memory space.
Supporting PCI access on new platforms
--------------------------------------
In order to support PCI resource mapping as described above, Linux platform
code must define HAVE_PCI_MMAP and provide a pci_mmap_page_range function.
Platforms are free to only support subsets of the mmap functionality, but
useful return codes should be provided.
Legacy resources are protected by the HAVE_PCI_LEGACY define. Platforms
wishing to support legacy functionality should define it and provide
pci_legacy_read, pci_legacy_write and pci_mmap_legacy_page_range functions.
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