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 #6:  uses the library for freeing rx buffers.

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

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

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

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

Patch #11: uses library helpers throughout.

Patch #12: refactor lan966x_fdma_reload() function.

[1] https://lore.kernel.org/netdev/20240902-fdma-sparx5-v1-0-1e7d5e5a9f34@microchip.com/Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
====================

Link: https://patch.msgid.link/20240905-fdma-lan966x-v1-0-e083f8620165@microchip.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

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

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

@@ -16,6 +16,7 @@
 #include <net/switchdev.h>
 #include <net/xdp.h>
 
+#include <fdma_api.h>
 #include <vcap_api.h>
 #include <vcap_api_client.h>
 
@@ -76,15 +77,6 @@
 
 #define FDMA_RX_DCB_MAX_DBS		1
 #define FDMA_TX_DCB_MAX_DBS		1
-#define FDMA_DCB_INFO_DATAL(x)		((x) & GENMASK(15, 0))
-
-#define FDMA_DCB_STATUS_BLOCKL(x)	((x) & GENMASK(15, 0))
-#define FDMA_DCB_STATUS_SOF		BIT(16)
-#define FDMA_DCB_STATUS_EOF		BIT(17)
-#define FDMA_DCB_STATUS_INTR		BIT(18)
-#define FDMA_DCB_STATUS_DONE		BIT(19)
-#define FDMA_DCB_STATUS_BLOCKO(x)	(((x) << 20) & GENMASK(31, 20))
-#define FDMA_DCB_INVALID_DATA		0x1
 
 #define FDMA_XTR_CHANNEL		6
 #define FDMA_INJ_CHANNEL		0
@@ -199,49 +191,14 @@ enum vcap_is1_port_sel_rt {
 
 struct lan966x_port;
 
-struct lan966x_db {
-	u64 dataptr;
-	u64 status;
-};
-
-struct lan966x_rx_dcb {
-	u64 nextptr;
-	u64 info;
-	struct lan966x_db db[FDMA_RX_DCB_MAX_DBS];
-};
-
-struct lan966x_tx_dcb {
-	u64 nextptr;
-	u64 info;
-	struct lan966x_db db[FDMA_TX_DCB_MAX_DBS];
-};
-
 struct lan966x_rx {
 	struct lan966x *lan966x;
 
-	/* Pointer to the array of hardware dcbs. */
-	struct lan966x_rx_dcb *dcbs;
-
-	/* Pointer to the last address in the dcbs. */
-	struct lan966x_rx_dcb *last_entry;
+	struct fdma fdma;
 
 	/* For each DB, there is a page */
 	struct page *page[FDMA_DCB_MAX][FDMA_RX_DCB_MAX_DBS];
 
-	/* Represents the db_index, it can have a value between 0 and
-	 * FDMA_RX_DCB_MAX_DBS, once it reaches the value of FDMA_RX_DCB_MAX_DBS
-	 * it means that the DCB can be reused.
-	 */
-	int db_index;
-
-	/* Represents the index in the dcbs. It has a value between 0 and
-	 * FDMA_DCB_MAX
-	 */
-	int dcb_index;
-
-	/* Represents the dma address to the dcbs array */
-	dma_addr_t dma;
-
 	/* Represents the page order that is used to allocate the pages for the
 	 * RX buffers. This value is calculated based on max MTU of the devices.
 	 */
@@ -252,8 +209,6 @@ struct lan966x_rx {
 	 */
 	u32 max_mtu;
 
-	u8 channel_id;
-
 	struct page_pool *page_pool;
 };
 
@@ -275,18 +230,11 @@ struct lan966x_tx_dcb_buf {
 struct lan966x_tx {
 	struct lan966x *lan966x;
 
-	/* Pointer to the dcb list */
-	struct lan966x_tx_dcb *dcbs;
-	u16 last_in_use;
-
-	/* Represents the DMA address to the first entry of the dcb entries. */
-	dma_addr_t dma;
+	struct fdma fdma;
 
 	/* Array of dcbs that are given to the HW */
 	struct lan966x_tx_dcb_buf *dcbs_buf;
 
-	u8 channel_id;
-
 	bool activated;
 };