Markus Stockhausen 0f7131baf3 realtek: rework hardware-assisted indirect mdio access ... With commit b53202a8c3 ("realtek: switch to use generic MDIO accessor functions") the phy access logic was enhanced. A quite big kernel patch was introduced that allowed to make use of hardware-assisted page access like we have in the realtek target. Basically it works the following way - The enhanced bus intercepts page write accesses - Currently selected pages are stored in internal vars. - Finally only all-in-one-consistent bus/register accesses are issued - It intercepted page changes and ensured that only a complete bus call For the details see https://github.com/openwrt/openwrt/pull/16172 Switching over to newer kernels this patch is really hard to maintain. Its heavy modifcations exist only in the realtek target. So it does not matter if we keep it as an kernel modification or directly include it in our driver. To make it the future brighter we drop this patch and take over its logic. Thus the kernel will stay totally modification-free. What do we do? 1. Up to now the bus->priv structure directly pointed to ethernet->priv. Create an explicit private structure rtl838x_bus_priv that not only holds the ethernet->priv pointer but also space for some bus status tracking vars as well. 2. Wherever we use a reference to ethernet->priv directly replace that by an additional indirection over the new rtl838x_bus_priv structure. 3. Up to now the phy flag PHY_HAS_REALTEK_PAGES identified that we can use the alternative paged access from the patch. As this will be no longer available remove it and provide read_page/write_page functions for each possible PHY. These functions will be pretty standard as for other Realtek PHYs. 4. The existing mdio bus read/write function rely on the classic MII_ADDR_C45 flag - one interface for two access types. This mixup will be removed on the way to kernel 6.6. In the future there will be two pairs of access functions. One for classic access one for c45 style access. Rewrite our functions into 3 parts: - a classic read/write function: ready for kernel 6.6 - a new c45 read/write function: ready for kernel 6.6 - a legacy read/write wrapper: for current 5.15 for the time being When we switch to 6.6 we only need to remove the legacy wrappers and link the new functions. Life can be so easy. 5. The classic read/write functions will incorporate the interception logic that was originally in the patch. 6. The package convenience functions that were embedded in the patch get lost as well. Rewrite them inside our phy driver. Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de> [Minor checkpatch.pl cleanups] Signed-off-by: Sander Vanheule <sander@svanheule.net>		2024-09-14 19:58:21 +02:00
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dsa/rtl83xx	realtek: rework hardware-assisted indirect mdio access	2024-09-14 19:58:21 +02:00
ethernet	realtek: rework hardware-assisted indirect mdio access	2024-09-14 19:58:21 +02:00
phy	realtek: rework hardware-assisted indirect mdio access	2024-09-14 19:58:21 +02:00