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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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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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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--- 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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+ /* 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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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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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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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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- 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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