[U-Boot] [PATCH 09/14] net: Add ability to set MAC address via EEPROM
Joe Hershberger
joe.hershberger at gmail.com
Wed Nov 30 21:00:49 CET 2016
On Fri, Nov 25, 2016 at 9:30 AM, Olliver Schinagl <oliver at schinagl.nl> wrote:
> This patch allows Kconfig to enable and set parameters to make it
> possible to read the MAC address from an EEPROM. The net core layer then
> uses this information to read MAC addresses from this EEPROM.
>
> Besides the various tuneables as to how to access the eeprom (bus,
> address, addressing mode/length, 2 configurable that are EEPROM generic
> (e.g. SPI or some other form of access) which are:
>
> NET_ETHADDR_EEPROM_OFFSET, indicating where in the EEPROM the start of
> the MAC address is. The default is 8 allowing for 8 bytes before the MAC
> for other purposes (header MAGIC for example).
>
> NET_ETHADDR_EEPROM_CRC8, indicating the MAC is appended with a CRC8-CCIT
> checksum that should be verified.
>
> Currently only I2C eeproms have been tested and thus only those options
> are available, but shouldn't be a limit. NET_ETHADDR_EEPROM_SPI can be
> just as created and added.
>
> The code currently first checks if there is a non-zero MAC address in
> the eeprom. If that fails to be the case, the read_rom_hwaddr can be
> used by a board to supply the MAC in other ways.
>
> If both these fails, the other code is still in place to query the
> environent, which then can be used to override the hardware supplied
> data.
>
> Signed-off-by: Olliver Schinagl <oliver at schinagl.nl>
> ---
> doc/README.enetaddr | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> include/net.h | 14 ++++++++
> net/Kconfig | 59 +++++++++++++++++++++++++++++++
> net/eth-uclass.c | 9 +++--
> net/eth_common.c | 34 ++++++++++++++++++
> net/eth_legacy.c | 2 ++
> 6 files changed, 214 insertions(+), 3 deletions(-)
>
> diff --git a/doc/README.enetaddr b/doc/README.enetaddr
> index 50e4899..89c1f7d 100644
> --- a/doc/README.enetaddr
> +++ b/doc/README.enetaddr
> @@ -47,6 +47,105 @@ Correct flow of setting up the MAC address (summarized):
> Previous behavior had the MAC address always being programmed into hardware
> in the device's init() function.
>
> +--------
> + EEPROM
> +--------
> +
> +Boards may come with an EEPROM specifically to store configuration bits, such
> +as a MAC address. Using CONFIG_NET_ETHADDR_EEPROM enables this feature.
> +Depending on the board, the EEPROM may be connected on various methods, but
> +currently, only the I2C bus can be used via CONFIG_NET_ETHADDR_EEPROM_I2C.
> +
> +The following config options are available,
> +CONFIG_NET_ETHADDR_EEPROM_I2C_BUS is the I2C bus on which the eeprom is present.
> +CONFIG_NET_ETHADDR_EEPROM_I2C_ADDR sets the address of the EEPROM, which
> +defaults to the very common 0x50. Small size EEPROM's generally use single byte
> +addressing but larger EEPROM's may use double byte addressing, which can be
> +configured using CONFIG_NET_ETHADDR_EEPROM_ADDRLEN.
> +
> +Within the EEPROM, the MAC address can be stored on any arbitrary offset,
> +CONFIG_NET_ETHADDR_EEPROM_OFFSET sets this to 8 as a default however, allowing
> +the first 8 bytes to be used for an optional data, for example a configuration
> +struct where the mac address is part of.
> +
> +Appending the 6 (ARP_HLEN) bytes is a CRC8 byte over the previous ARP_HLEN
> +bytes. Whether to check this CRC8 or not is dependent on
> +CONFIG_NET_ETHADDR_EEPROM_CRC8.
> +
> +To keep things nicely aligned, a final 'reserved' byte is added to the mac
> +address + crc8 combo.
> +
> +A board may want to store more information in its eeprom, using the following
> +example layout, this can be achieved.
> +
> +struct mac_addr {
> + uint8_t mac[ARP_HLEN];
> + uint8_t crc8;
> + uint8_t reserved;
> +};
> +
> +struct config_eeprom {
> + uint32_t magic;
> + uint8_t version;
> + uint8_t reserved[2];
> + uint8_t mac_cnt;
> + struct mac_addr[mac_cnt];
> +};
> +
> +Filling this in:
> +struct config_eeprom eeprom = {
> + .magic = { 'M', 'g', 'i', 'c' },
> + .reserved = { 0x00, 0x00 },
> + .mac_cnt = 2,
> + .mac_addr = {
> + {
> + .mac = {
> + 0x01, 0x23, 0x45,
> + 0x67, 0x89, 0xab,
> + },
> + .crc8 = 0xbe,
> + .reserved = 0x00,
> + }, {
> + .mac = {
> + 0xba, 0x98, 0x76,
> + 0x54, 0x32, 0x10,
> + },
> + .crc8 = 0x82,
> + .reserved = 0x00,
> + },
> + },
> +};
> +
> +The eeprom content would look like this.
> +
> +00000000 4d 67 69 63 01 00 00 02 01 23 45 67 89 ab be 00 |Mgic.....#Eg....|
> +00000010 ba 98 76 54 32 10 82 00 |..vT2...|
> +
> +This can be done from linux using the i2c-tools:
> +
> +i2cset I2CBUS 0x50 0x08 0x01
> +i2cset I2CBUS 0x50 0x09 0x23
> +i2cset I2CBUS 0x50 0x0a 0x45
> +i2cset I2CBUS 0x50 0x0b 0x67
> +i2cset I2CBUS 0x50 0x0c 0x89
> +i2cset I2CBUS 0x50 0x0d 0xab
> +i2cset I2CBUS 0x50 0x0e 0xbe
> +
> +Alternativly this can be done from the u-boot console as:
> +
> +u-boot> mm.b 0
> +00000000: 00 ? 01
> +00000001: 23 ? 23
> +00000002: 45 ? 45
> +00000003: 67 ? 67
> +00000004: 89 ? 89
> +00000005: ab ? ab
> +00000006: be ? be
> +00000007: 00 ? q
> +i2c dev I2CBUS
> +i2c write 0 50 8 7
> +i2c md 50 8
> +
> -------
> Usage
> -------
> diff --git a/include/net.h b/include/net.h
> index 08f8af8..e50ab5d 100644
> --- a/include/net.h
> +++ b/include/net.h
> @@ -248,6 +248,20 @@ int eth_getenv_enetaddr(const char *name, uchar *enetaddr);
> int eth_setenv_enetaddr(const char *name, const uchar *enetaddr);
>
> /**
> + * eeprom_read_enetaddr() - Read the hardware address from an eeprom
> + *
> + * This function tries to read the MAC address from an eeprom as can be read
> + * in docs/README.enetaddr.
> + *
> + * @index: index of the interface to get the hwaddr for
> + * @enetaddr: pointer for the found hwaddr. Needs to be atleast ARP_HLEN
> + * @return: 0 on success, non-zero is error status. Additionally hwaddr
> + * is set to 00:00:00:00:00. This is also the case if
> + * CONFIG_NET_ETHADDR_EEPROM is not set.
> + */
> +int eeprom_read_enetaddr(const int index, unsigned char *enetaddr);
> +
> +/**
> * eth_setenv_enetaddr_by_index() - set the MAC address environment variable
> *
> * This sets up an environment variable with the given MAC address (@enetaddr).
> diff --git a/net/Kconfig b/net/Kconfig
> index 414c549..f699e1c 100644
> --- a/net/Kconfig
> +++ b/net/Kconfig
> @@ -7,6 +7,65 @@ menuconfig NET
>
> if NET
>
> +config NET_ETHADDR_EEPROM
> + bool "Get ethaddr from eeprom"
> + help
> + Selecting this will try to get the Ethernet address from an onboard
> + EEPROM and set into the environment if and only if the environment
> + does currently not already hold a MAC address. For more information
> + see doc/README.enetaddr.
> +
> +config NET_ETHADDR_EEPROM_I2C
> + depends on NET_ETHADDR_EEPROM
> + bool "EEPROM on I2C bus"
> + help
> + This switch enables checks for an EEPROM on the I2C bus. Naturally
> + this will only work if there is an actual EEPROM connected on the
> + I2C bus and the bus and device are properly configured via the
> + options below.
> +
> +config NET_ETHADDR_EEPROM_I2C_BUS
> + depends on NET_ETHADDR_EEPROM_I2C
> + int "I2C bus"
> + default 0
> + help
> + Select the bus on which the EEPROM is present, defaults to bus 0.
> + Remember to also make the selected bus available via I2Cn_ENABLE.
> +
> +config NET_ETHADDR_EEPROM_I2C_ADDR
> + depends on NET_ETHADDR_EEPROM_I2C
> + hex "EEPROM address"
> + default 0x50
> + help
> + Select the address of the EEPROM, defaults to address 0x50.
> +
> +config NET_ETHADDR_EEPROM_I2C_ADDRLEN
> + depends on NET_ETHADDR_EEPROM_I2C
> + int "EEPROM address length"
> + default 1
> + help
> + Number of bytes to be used for the I2C address length. Typically 1,
> + 2 for large memories, 0 for register type devices with only one
> + register.
> +
> +config NET_ETHADDR_EEPROM_OFFSET
> + depends on NET_ETHADDR_EEPROM
> + int "EEPROM offset"
> + default 8
> + help
> + Select the byte offset of the MAC address within the page,
> + defaults to byte 8.
> +
> +config NET_ETHADDR_EEPROM_CRC8
> + depends on NET_ETHADDR_EEPROM
> + bool "Check CRC8 of MAC"
> + default y
> + help
> + Optionally, it is possible to run a CRC-8-CCITT check on the MAC
> + address. To do so, the MAC address is stored with a CRC8 byte append.
> + This option enables the CRC check of the MAC address against the CRC
> + byte.
> +
> config NET_RANDOM_ETHADDR
> bool "Random ethaddr if unset"
> select LIB_RAND
> diff --git a/net/eth-uclass.c b/net/eth-uclass.c
> index 5c888b8..a154a7e 100644
> --- a/net/eth-uclass.c
> +++ b/net/eth-uclass.c
> @@ -491,9 +491,12 @@ static int eth_post_probe(struct udevice *dev)
>
> priv->state = ETH_STATE_INIT;
>
> - /* Check if the device has a MAC address in ROM */
> - if (eth_get_ops(dev)->read_rom_hwaddr)
> - eth_get_ops(dev)->read_rom_hwaddr(dev);
> + /* Check if the device has a MAC address in EEPROM */
> + eeprom_read_enetaddr(dev->seq, pdata->enetaddr);
> + if (is_zero_ethaddr(pdata->enetaddr))
> + /* Check if the device has a MAC address in ROM */
> + if (eth_get_ops(dev)->read_rom_hwaddr)
> + eth_get_ops(dev)->read_rom_hwaddr(dev);
>
> eth_getenv_enetaddr_by_index("eth", dev->seq, env_enetaddr);
> if (!is_zero_ethaddr(env_enetaddr)) {
> diff --git a/net/eth_common.c b/net/eth_common.c
> index 079be89..e0d8b62 100644
> --- a/net/eth_common.c
> +++ b/net/eth_common.c
> @@ -8,10 +8,44 @@
>
> #include <common.h>
> #include <dm.h>
> +#include <i2c.h>
> #include <miiphy.h>
> #include <net.h>
> #include "eth_internal.h"
>
> +int eeprom_read_enetaddr(const int index, unsigned char *enetaddr)
> +{
> + uint8_t eeprom[ARP_HLEN + 1] = { 0x00 };
> +#if defined(CONFIG_NET_ETHADDR_EEPROM) && defined(CONFIG_NET_ETHADDR_EEPROM_I2C)
Since it is easily reasonable that SPI PROM is a likely useful
support, why not keep the layout stuff separate from the I2C stuff so
that it is trivial to plug in a different bus later? It will also make
the code clearer by untangling these.
> + int old_i2c_bus;
> +
> + old_i2c_bus = i2c_get_bus_num();
> + if (old_i2c_bus != CONFIG_NET_ETHADDR_EEPROM_I2C_BUS)
> + i2c_set_bus_num(CONFIG_NET_ETHADDR_EEPROM_I2C_BUS);
> + /* Skip in blocks of 8 (ARP + CRC8 + pad), but read 7 from the eeprom */
> + if (i2c_read(CONFIG_NET_ETHADDR_EEPROM_I2C_ADDR,
> + CONFIG_NET_ETHADDR_EEPROM_OFFSET + (index * (ARP_HLEN + 2)),
> + CONFIG_NET_ETHADDR_EEPROM_I2C_ADDRLEN,
> + eeprom, ARP_HLEN + 1)) {
> + i2c_set_bus_num(old_i2c_bus);
> + puts("Could not read the EEPROM or EEPROM missing on device: ");
> + return -ENOSYS;
> + }
> + i2c_set_bus_num(old_i2c_bus);
> +
> +#ifdef CONFIG_NET_ETHADDR_EEPROM_CRC8
> + if (crc8(0, eeprom, ARP_HLEN) != eeprom[ARP_HLEN]) {
> + puts("CRC error on MAC address from EEPROM on device: ");
> + return -EINVAL;
> + }
> +#endif
> +#endif
> +
> + memcpy(enetaddr, eeprom, ARP_HLEN);
> +
> + return 0;
> +}
> +
> void eth_parse_enetaddr(const char *addr, uchar *enetaddr)
> {
> char *end;
> diff --git a/net/eth_legacy.c b/net/eth_legacy.c
> index bf4de37..8fb5844 100644
> --- a/net/eth_legacy.c
> +++ b/net/eth_legacy.c
> @@ -136,6 +136,8 @@ int eth_write_hwaddr(struct eth_device *dev, const char *base_name,
> unsigned char env_enetaddr[ARP_HLEN];
> int ret = 0;
>
> + eeprom_read_enetaddr(eth_number, dev->enetaddr);
> +
> eth_getenv_enetaddr_by_index(base_name, eth_number, env_enetaddr);
>
> if (!is_zero_ethaddr(env_enetaddr)) {
> --
> 2.10.2
>
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