Merge branch 'net-lan966x-use-the-newly-introduced-fdma-library'

Daniel Machon says:

====================
net: lan966x: use the newly introduced FDMA library

This patch series is the second of a 2-part series [1], that adds a new
common FDMA library for Microchip switch chips Sparx5 and lan966x. These
chips share the same FDMA engine, and as such will benefit from a common
library with a common implementation.  This also has the benefit of
removing a lot of open-coded bookkeeping and duplicate code for the two
drivers.

In this second series, the FDMA library will be taken into use by the
lan966x switch driver.

 ###################
 # Example of use: #
 ###################

- Initialize the rx and tx fdma structs with values for: number of
  DCB's, number of DB's, channel ID, DB size (data buffer size), and
  total size of the requested memory. Also provide two callbacks:
  nextptr_cb() and dataptr_cb() for getting the nextptr and dataptr.

- Allocate memory using fdma_alloc_phys() or fdma_alloc_coherent().

- Initialize the DCB's with fdma_dcb_init().

- Add new DCB's with fdma_dcb_add().

- Free memory with fdma_free_phys() or fdma_free_coherent().

 #####################
 # Patch  breakdown: #
 #####################

Patch #1:  select FDMA library for lan966x.

Patch #2:  includes the fdma_api.h header and removes old symbols.

Patch #3:  replaces old rx and tx variables with equivalent ones from the
           fdma struct. Only the variables that can be changed without
           breaking traffic is changed in this patch.

Patch #4:  uses the library for allocation of rx buffers. This requires
           quite a bit of refactoring in this single patch.

Patch #5:  uses the library for adding DCB's in the rx path.

Patch torvalds#6:  uses the library for freeing rx buffers.

Patch torvalds#7:  uses the library for allocation of tx buffers. This requires
           quite a bit of refactoring in this single patch.

Patch torvalds#8:  uses the library for adding DCB's in the tx path.

Patch torvalds#9:  uses the library helpers in the tx path.

Patch torvalds#10: ditch last_in_use variable and use library instead.

Patch torvalds#11: uses library helpers throughout.

Patch torvalds#12: refactor lan966x_fdma_reload() function.

[1] https://lore.kernel.org/netdev/[email protected]/

Signed-off-by: Daniel Machon <[email protected]>
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

drivers/net/ethernet/microchip/lan966x/Kconfig

@@ -8,6 +8,7 @@ config LAN966X_SWITCH
 	select PHYLINK
 	select PAGE_POOL
 	select VCAP
+	select FDMA
 	help
 	  This driver supports the Lan966x network switch device.
 

drivers/net/ethernet/microchip/lan966x/Makefile

@@ -20,3 +20,4 @@ lan966x-switch-$(CONFIG_DEBUG_FS) += lan966x_vcap_debugfs.o
 
 # Provide include files
 ccflags-y += -I$(srctree)/drivers/net/ethernet/microchip/vcap
+ccflags-y += -I$(srctree)/drivers/net/ethernet/microchip/fdma