net: extend eth_platform_get_mac_address()
Subsystems (2)
v3 cover net: extend eth_platform_get_mac_address()
This is a follow-up to a series I posted a while ago the goal of which was to replace the at24 platform data with device properties. To do so we need to somehow remove reading the MAC address from relevant board files.
In my patches I used nvmem and MTD to read the MAC address from within the davinci emac driver. It was suggested that we generalize it further but since MTD doesn't support nvmem yet, the best we can do is to move this code over to net core code.
The following patches modify the eth_platform_get_mac_address() function which seems to be the best candidate for this code.
The first patch splits the function into two subroutines.
The last two patches add nvmem and MTD support to the function. In order to stay compatible with existing users, nvmem and MTD will be tried last - after device tree and arch-specific callback.
If this series gets accepted I will modify my previous patches to use it instead of handcoding the same operations in davinci_emac.
v1 -> v2:
- dropped patches 1 & 2
- improved the MAC address verification and fixed a potential buffer overflow in patch 2/3
v2 -> v3:
- in patch 1: split the function into subroutines in preparation for nvmem and MTD support
- modify patches 2 & 3 so that they have a separate function for each new MAC address source
Bartosz Golaszewski (3):
net: split eth_platform_get_mac_address() into subroutines
net: add support for nvmem to eth_platform_get_mac_address()
net: add MTD support to eth_platform_get_mac_address()
net/ethernet/eth.c | 117 ++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 106 insertions(+), 11 deletions(-)
Signature · 1 line
2.17.1
PATCH v3 1/3 net: split eth_platform_get_mac_address() into subroutines
From: Bartosz Golaszewski <[email protected]>
We want do add more sources from which to read the MAC address. In order to avoid bloating this function too much, start by splitting it into subroutines, each of which takes care of reading the MAC from one source.
--- net/ethernet/eth.c | 48 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 11 deletions(-)
net/ethernet/eth.c +37 -11
@@ -525,26 +525,52 @@ unsigned char * __weak arch_get_platform_mac_address(void)return NULL ; } -int eth_platform_get_mac_address (struct device *dev,u8 *mac_addr) +static int mac_address_from_of (struct device *dev,u8 *mac_addr) {const unsigned char *addr; -struct device_node *dp; +struct device_node *np; -if (dev_is_pci (dev)) - dp =pci_device_to_OF_node (to_pci_dev (dev)); -else - dp = dev->of_node; + np =dev_is_pci (dev) ?pci_device_to_OF_node (to_pci_dev (dev)) + : dev->of_node; - addr =NULL ; -if (dp) - addr =of_get_mac_address (dp); -if (!addr) - addr =arch_get_platform_mac_address (); +if (!np) +return -ENODEV ; + addr =of_get_mac_address (np);if (!addr)return -ENODEV ; +if (!addr || !is_valid_ether_addr (addr)) +return -ENODEV ; + +ether_addr_copy (mac_addr, addr); +return 0 ; +} + +static int mac_address_from_arch (u8 *mac_addr) +{ +const unsigned char *addr; + + addr =arch_get_platform_mac_address (); +if (!addr || !is_valid_ether_addr (addr)) +return -ENODEV ; +ether_addr_copy (mac_addr, addr);return 0 ; } + +int eth_platform_get_mac_address (struct device *dev,u8 *mac_addr) +{ +int rv; + + rv =mac_address_from_of (dev, mac_addr); +if (!rv) +return 0 ; + + rv =mac_address_from_arch (mac_addr); +if (!rv) +return 0 ; + +return -ENODEV ; +}EXPORT_SYMBOL (eth_platform_get_mac_address);
Signature · 1 line
2.17.1
PATCH v3 2/3 net: add support for nvmem to eth_platform_get_mac_address()
In reply to Bartosz GolaszewskiFrom: Bartosz Golaszewski <[email protected]>
Many non-DT platforms read the MAC address from EEPROM. Usually it's either done with callbacks defined in board files or from SoC-specific ethernet drivers.
In order to generalize this, try to read the MAC from nvmem in eth_platform_get_mac_address() using a standard lookup name:
"mac-address".
--- net/ethernet/eth.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
net/ethernet/eth.c +38 -0
@@ -54,6 +54,7 @@#include <linux/if_ether.h> #include <linux/of_net.h> #include <linux/pci.h> +#include <linux/nvmem-consumer.h> #include <net/dst.h> #include <net/arp.h> #include <net/sock.h>
@@ -559,6 +560,39 @@ static int mac_address_from_arch(u8 *mac_addr)return 0 ; } +static int mac_address_from_nvmem (struct device *dev,u8 *mac_addr) +{ +const unsigned char *addr; +struct nvmem_cell *cell; +size_t alen; +int rv =0 ; + + cell =nvmem_cell_get (dev,"mac-address" ); +if (IS_ERR (cell)) +return PTR_ERR (cell); + + addr =nvmem_cell_read (cell, &alen); +if (IS_ERR (addr)) { + rv =PTR_ERR (addr); + goto put_nvmem; + } + +if (alen !=ETH_ALEN || !is_valid_ether_addr (addr)) { + rv = -ENODEV ; + goto free_addr; + } + +ether_addr_copy (mac_addr, addr); + +free_addr: +kfree (addr); + +put_nvmem: +nvmem_cell_put (cell); + +return rv; +} +int eth_platform_get_mac_address (struct device *dev,u8 *mac_addr) {int rv;
@@ -571,6 +605,10 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)if (!rv)return 0 ; + rv =mac_address_from_nvmem (dev, mac_addr); +if (!rv) +return 0 ; +return -ENODEV ; }EXPORT_SYMBOL (eth_platform_get_mac_address);
Signature · 1 line
2.17.1
PATCH v3 3/3 net: add MTD support to eth_platform_get_mac_address()
In reply to Bartosz GolaszewskiFrom: Bartosz Golaszewski <[email protected]>
MTD doesn't support nvmem yet. Some platforms use MTD to read the MAC address from SPI flash. If we want this function to generalize reading the MAC address, we need to separately try to use MTD.
--- net/ethernet/eth.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-)
net/ethernet/eth.c +32 -1
@@ -55,6 +55,7 @@#include <linux/of_net.h> #include <linux/pci.h> #include <linux/nvmem-consumer.h> +#include <linux/mtd/mtd.h> #include <net/dst.h> #include <net/arp.h> #include <net/sock.h>
@@ -593,6 +594,36 @@ static int mac_address_from_nvmem(struct device *dev, u8 *mac_addr)return rv; } +#ifdef CONFIG_MTD +static int mac_address_from_mtd (u8 *mac_addr) +{ +struct mtd_info *mtd; +size_t alen; +int rv =0 ; + + mtd =get_mtd_device_nm ("MAC-Address" ); +if (IS_ERR (mtd)) +return PTR_ERR (mtd); + + rv =mtd_read (mtd,0 ,ETH_ALEN , &alen, mac_addr); +if (rv) + goto put_mtd; + +if (alen !=ETH_ALEN || !is_valid_ether_addr (mac_addr)) + rv = -ENODEV ; + +put_mtd: +put_mtd_device (mtd); + +return rv; +} +#else /* CONFIG_MTD */ +static int mac_address_from_mtd (u8 *mac_addr) +{ +return -ENODEV ; +} +#endif /* CONFIG_MTD */ +int eth_platform_get_mac_address (struct device *dev,u8 *mac_addr) {int rv;
@@ -609,6 +640,6 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr)if (!rv)return 0 ; -return -ENODEV ; +return mac_address_from_mtd (mac_addr); }EXPORT_SYMBOL (eth_platform_get_mac_address);
Signature · 1 line
2.17.1
Re: [PATCH v3 3/3] net: add MTD support to eth_platform_get_mac_address()
Quoted 5 lines · Bartosz Golaszewski
From: Bartosz Golaszewski <[email protected]>
MTD doesn't support nvmem yet. Some platforms use MTD to read the MAC address from SPI flash. If we want this function to generalize reading the MAC address, we need to separately try to use MTD.
How many board files are doing this? It is only worth generlizing if there are a number of board files, all just pulling 6 bytes out from the beginning of an MTD partition.
It is also normal to actually add a user of a new feature at the same time as the new feature. It can be messy when it is across subsystem boundaries, but please at least try.
Andrew