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	Fix mac address increment patch. Permit to overflow to the next
byte and correctly calculate the incremented mac.
Reported-by: Chen Minqiang <ptpt52@gmail.com>
Fixes: d284e6ef0f ("treewide: convert mtd-mac-address-increment* to generic implementation")
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
		
	
			
		
			
				
	
	
		
			90 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			90 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From 844c273286f328acf0dab5fbd5d864366b4904dc Mon Sep 17 00:00:00 2001
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| From: Ansuel Smith <ansuelsmth@gmail.com>
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| Date: Tue, 30 Mar 2021 18:21:14 +0200
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| Subject: [PATCH] of_net: add mac-address-increment support
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| 
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| Lots of embedded devices use the mac-address of other interface
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| extracted from nvmem cells and increments it by one or two. Add two
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| bindings to integrate this and directly use the right mac-address for
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| the interface. Some example are some routers that use the gmac
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| mac-address stored in the art partition and increments it by one for the
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| wifi. mac-address-increment-byte bindings is used to tell what byte of
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| the mac-address has to be increased (if not defined the last byte is
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| increased) and mac-address-increment tells how much the byte decided
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| early has to be increased.
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| 
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| Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
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| ---
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|  drivers/of/of_net.c | 43 +++++++++++++++++++++++++++++++++++++++----
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|  1 file changed, 39 insertions(+), 4 deletions(-)
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| 
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| --- a/drivers/of/of_net.c
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| +++ b/drivers/of/of_net.c
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| @@ -115,27 +115,62 @@ static int of_get_mac_addr_nvmem(struct
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|   * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
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|   * but is all zeros.
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|   *
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| + * DT can tell the system to increment the mac-address after is extracted by
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| + * using:
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| + * - mac-address-increment-byte to decide what byte to increase
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| + *   (if not defined is increased the last byte)
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| + * - mac-address-increment to decide how much to increase. The value WILL
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| + *   overflow to other bytes if the increment is over 255 or the total
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| + *   increment will exceed 255 of the current byte.
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| + *   (example 00:01:02:03:04:ff + 1 == 00:01:02:03:05:00)
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| + *   (example 00:01:02:03:04:fe + 5 == 00:01:02:03:05:03)
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| + *
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|   * Return: 0 on success and errno in case of error.
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|  */
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|  int of_get_mac_address(struct device_node *np, u8 *addr)
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|  {
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| +	u32 inc_idx, mac_inc, mac_val;
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|  	int ret;
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|  
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| +	/* Check first if the increment byte is present and valid.
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| +	 * If not set assume to increment the last byte if found.
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| +	 */
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| +	if (of_property_read_u32(np, "mac-address-increment-byte", &inc_idx))
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| +		inc_idx = 5;
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| +	if (inc_idx < 3 || inc_idx > 5)
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| +		return -EINVAL;
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| +
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|  	if (!np)
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|  		return -ENODEV;
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|  
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|  	ret = of_get_mac_addr(np, "mac-address", addr);
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|  	if (!ret)
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| -		return 0;
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| +		goto found;
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|  
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|  	ret = of_get_mac_addr(np, "local-mac-address", addr);
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|  	if (!ret)
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| -		return 0;
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| +		goto found;
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|  
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|  	ret = of_get_mac_addr(np, "address", addr);
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|  	if (!ret)
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| -		return 0;
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| +		goto found;
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| +
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| +	ret = of_get_mac_addr_nvmem(np, addr);
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| +	if (ret)
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| +		return ret;
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| +
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| +found:
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| +	if (!of_property_read_u32(np, "mac-address-increment", &mac_inc)) {
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| +		/* Convert to a contiguous value */
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| +		mac_val = (addr[3] << 16) + (addr[4] << 8) + addr[5];
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| +		mac_val += mac_inc << 8 * (5-inc_idx);
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| +
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| +		/* Apply the incremented value handling overflow case */
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| +		addr[3] = (mac_val >> 16) & 0xff;
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| +		addr[4] = (mac_val >> 8) & 0xff;
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| +		addr[5] = (mac_val >> 0) & 0xff;
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| +	}
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|  
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| -	return of_get_mac_addr_nvmem(np, addr);
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| +	return ret;
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|  }
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|  EXPORT_SYMBOL(of_get_mac_address);
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