bng_en: Add ring memory allocation support

Add ring allocation/free mechanism which help
to allocate rings (TX/RX/Completion) and backing
stores memory on the host for the device.
Future patches will use these functions.

Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Bhargava Chenna Marreddy <bhargava.marreddy@broadcom.com>
Reviewed-by: Rajashekar Hudumula <rajashekar.hudumula@broadcom.com>
Link: https://patch.msgid.link/20250701143511.280702-6-vikas.gupta@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bnge/Makefile

@@ -5,4 +5,5 @@ obj-$(CONFIG_BNGE) += bng_en.o
 bng_en-y := bnge_core.o \
 	    bnge_devlink.o \
 	    bnge_hwrm.o \
-	    bnge_hwrm_lib.o
+	    bnge_hwrm_lib.o \
+	    bnge_rmem.o

drivers/net/ethernet/broadcom/bnge/bnge_rmem.c

@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2025 Broadcom.
+
+#include <linux/etherdevice.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/mm.h>
+#include <linux/dma-mapping.h>
+#include <linux/vmalloc.h>
+#include <linux/crash_dump.h>
+
+#include "bnge.h"
+#include "../bnxt/bnxt_hsi.h"
+#include "bnge_hwrm_lib.h"
+#include "bnge_rmem.h"
+
+void bnge_free_ring(struct bnge_dev *bd, struct bnge_ring_mem_info *rmem)
+{
+	struct pci_dev *pdev = bd->pdev;
+	int i;
+
+	if (!rmem->pg_arr)
+		goto skip_pages;
+
+	for (i = 0; i < rmem->nr_pages; i++) {
+		if (!rmem->pg_arr[i])
+			continue;
+
+		dma_free_coherent(&pdev->dev, rmem->page_size,
+				  rmem->pg_arr[i], rmem->dma_arr[i]);
+
+		rmem->pg_arr[i] = NULL;
+	}
+skip_pages:
+	if (rmem->pg_tbl) {
+		size_t pg_tbl_size = rmem->nr_pages * 8;
+
+		if (rmem->flags & BNGE_RMEM_USE_FULL_PAGE_FLAG)
+			pg_tbl_size = rmem->page_size;
+		dma_free_coherent(&pdev->dev, pg_tbl_size,
+				  rmem->pg_tbl, rmem->dma_pg_tbl);
+		rmem->pg_tbl = NULL;
+	}
+	if (rmem->vmem_size && *rmem->vmem) {
+		vfree(*rmem->vmem);
+		*rmem->vmem = NULL;
+	}
+}
+
+int bnge_alloc_ring(struct bnge_dev *bd, struct bnge_ring_mem_info *rmem)
+{
+	struct pci_dev *pdev = bd->pdev;
+	u64 valid_bit = 0;
+	int i;
+
+	if (rmem->flags & (BNGE_RMEM_VALID_PTE_FLAG | BNGE_RMEM_RING_PTE_FLAG))
+		valid_bit = PTU_PTE_VALID;
+
+	if ((rmem->nr_pages > 1 || rmem->depth > 0) && !rmem->pg_tbl) {
+		size_t pg_tbl_size = rmem->nr_pages * 8;
+
+		if (rmem->flags & BNGE_RMEM_USE_FULL_PAGE_FLAG)
+			pg_tbl_size = rmem->page_size;
+		rmem->pg_tbl = dma_alloc_coherent(&pdev->dev, pg_tbl_size,
+						  &rmem->dma_pg_tbl,
+						  GFP_KERNEL);
+		if (!rmem->pg_tbl)
+			return -ENOMEM;
+	}
+
+	for (i = 0; i < rmem->nr_pages; i++) {
+		u64 extra_bits = valid_bit;
+
+		rmem->pg_arr[i] = dma_alloc_coherent(&pdev->dev,
+						     rmem->page_size,
+						     &rmem->dma_arr[i],
+						     GFP_KERNEL);
+		if (!rmem->pg_arr[i])
+			return -ENOMEM;
+
+		if (rmem->nr_pages > 1 || rmem->depth > 0) {
+			if (i == rmem->nr_pages - 2 &&
+			    (rmem->flags & BNGE_RMEM_RING_PTE_FLAG))
+				extra_bits |= PTU_PTE_NEXT_TO_LAST;
+			else if (i == rmem->nr_pages - 1 &&
+				 (rmem->flags & BNGE_RMEM_RING_PTE_FLAG))
+				extra_bits |= PTU_PTE_LAST;
+			rmem->pg_tbl[i] =
+				cpu_to_le64(rmem->dma_arr[i] | extra_bits);
+		}
+	}
+
+	if (rmem->vmem_size) {
+		*rmem->vmem = vzalloc(rmem->vmem_size);
+		if (!(*rmem->vmem))
+			return -ENOMEM;
+	}
+
+	return 0;
+}

drivers/net/ethernet/broadcom/bnge/bnge_rmem.h

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2025 Broadcom */
+
+#ifndef _BNGE_RMEM_H_
+#define _BNGE_RMEM_H_
+
+#define PTU_PTE_VALID             0x1UL
+#define PTU_PTE_LAST              0x2UL
+#define PTU_PTE_NEXT_TO_LAST      0x4UL
+
+struct bnge_ring_mem_info {
+	/* Number of pages to next level */
+	int			nr_pages;
+	int			page_size;
+	u16			flags;
+#define BNGE_RMEM_VALID_PTE_FLAG	1
+#define BNGE_RMEM_RING_PTE_FLAG		2
+#define BNGE_RMEM_USE_FULL_PAGE_FLAG	4
+
+	u16			depth;
+
+	void			**pg_arr;
+	dma_addr_t		*dma_arr;
+
+	__le64			*pg_tbl;
+	dma_addr_t		dma_pg_tbl;
+
+	int			vmem_size;
+	void			**vmem;
+};
+
+int bnge_alloc_ring(struct bnge_dev *bd, struct bnge_ring_mem_info *rmem);
+void bnge_free_ring(struct bnge_dev *bd, struct bnge_ring_mem_info *rmem);
+
+#endif /* _BNGE_RMEM_H_ */