[PATCH iwl-next 03/14] libeth: add PCI device initialization helpers to libeth

[Larysa Zaremba]

From: Phani R Burra <phani.r.burra@xxxxxxxxx>

Add memory related support functions for drivers to access MMIO space and
allocate/free dma buffers.

Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
Signed-off-by: Phani R Burra <phani.r.burra@xxxxxxxxx>
Co-developed-by: Victor Raj <victor.raj@xxxxxxxxx>
Signed-off-by: Victor Raj <victor.raj@xxxxxxxxx>
Co-developed-by: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx>
Signed-off-by: Sridhar Samudrala <sridhar.samudrala@xxxxxxxxx>
Co-developed-by: Pavan Kumar Linga <pavan.kumar.linga@xxxxxxxxx>
Signed-off-by: Pavan Kumar Linga <pavan.kumar.linga@xxxxxxxxx>
Co-developed-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
 drivers/net/ethernet/intel/libeth/Kconfig  |   6 +
 drivers/net/ethernet/intel/libeth/Makefile |   4 +
 drivers/net/ethernet/intel/libeth/pci.c    | 184 +++++++++++++++++++++
 include/net/libeth/pci.h                   |  55 ++++++
 4 files changed, 249 insertions(+)
 create mode 100644 drivers/net/ethernet/intel/libeth/pci.c
 create mode 100644 include/net/libeth/pci.h

diff --git a/drivers/net/ethernet/intel/libeth/Kconfig b/drivers/net/ethernet/intel/libeth/Kconfig
index 480293b71dbc..070ad685fb74 100644
--- a/drivers/net/ethernet/intel/libeth/Kconfig
+++ b/drivers/net/ethernet/intel/libeth/Kconfig
@@ -7,3 +7,9 @@ config LIBETH
 	help
 	  libeth is a common library containing routines shared between several
 	  drivers, but not yet promoted to the generic kernel API.
+
+config LIBETH_PCI
+	tristate
+	help
+	  Helper functions for management of PCI resources belonging
+	  to networking devices.
diff --git a/drivers/net/ethernet/intel/libeth/Makefile b/drivers/net/ethernet/intel/libeth/Makefile
index 52492b081132..5f0fc9446acb 100644
--- a/drivers/net/ethernet/intel/libeth/Makefile
+++ b/drivers/net/ethernet/intel/libeth/Makefile
@@ -4,3 +4,7 @@
 obj-$(CONFIG_LIBETH)		+= libeth.o
 
 libeth-y			:= rx.o
+
+obj-$(CONFIG_LIBETH_PCI)	+= libeth_pci.o
+
+libeth_pci-y			:= pci.o
diff --git a/drivers/net/ethernet/intel/libeth/pci.c b/drivers/net/ethernet/intel/libeth/pci.c
new file mode 100644
index 000000000000..63cf56a07ce9
--- /dev/null
+++ b/drivers/net/ethernet/intel/libeth/pci.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2025 Intel Corporation */
+
+#include <net/libeth/pci.h>
+
+/**
+ * libeth_find_mmio_region - find if MMIO region is present in the list
+ * @mmio_list: list that contains MMIO region info
+ * @offset: MMIO region start offset
+ * @bar_idx: BAR index where the offset to search
+ *
+ * Return: MMIO region pointer or NULL if the region info is not present.
+ */
+static struct libeth_pci_mmio_region *
+libeth_find_mmio_region(const struct list_head *mmio_list,
+			resource_size_t offset, int bar_idx)
+{
+	struct libeth_pci_mmio_region *mr;
+
+	list_for_each_entry(mr, mmio_list, list)
+		if (mr->bar_idx == bar_idx && mr->offset == offset)
+			return mr;
+
+	return NULL;
+}
+
+/**
+ * __libeth_pci_get_mmio_addr - get the MMIO virtual address
+ * @mmio_info: contains list of MMIO regions
+ * @offset: register offset of find
+ * @num_args: number of additional arguments present
+ *
+ * This function finds the virtual address of a register offset by iterating
+ * through the non-linear MMIO regions that are mapped by the driver.
+ *
+ * Return: valid MMIO virtual address or NULL.
+ */
+void __iomem *__libeth_pci_get_mmio_addr(struct libeth_mmio_info *mmio_info,
+					 resource_size_t offset,
+					 int num_args, ...)
+{
+	struct libeth_pci_mmio_region *mr;
+	int bar_idx = 0;
+	va_list args;
+
+	if (num_args) {
+		va_start(args, num_args);
+		bar_idx = va_arg(args, int);
+		va_end(args);
+	}
+
+	list_for_each_entry(mr, &mmio_info->mmio_list, list)
+		if (bar_idx == mr->bar_idx && offset >= mr->offset &&
+		    offset < mr->offset + mr->size) {
+			offset -= mr->offset;
+
+			return mr->addr + offset;
+		}
+
+	return NULL;
+}
+EXPORT_SYMBOL_NS_GPL(__libeth_pci_get_mmio_addr, "LIBETH_PCI");
+
+/**
+ * __libeth_pci_map_mmio_region - map PCI device MMIO region
+ * @mmio_info: struct to store the mapped MMIO region
+ * @offset: MMIO region start offset
+ * @size: MMIO region size
+ * @num_args: number of additional arguments present
+ *
+ * Return: true on success, false on memory map failure.
+ */
+bool __libeth_pci_map_mmio_region(struct libeth_mmio_info *mmio_info,
+				  resource_size_t offset,
+				  resource_size_t size, int num_args, ...)
+{
+	struct pci_dev *pdev = mmio_info->pdev;
+	struct libeth_pci_mmio_region *mr;
+	resource_size_t pa;
+	void __iomem *va;
+	int bar_idx = 0;
+	va_list args;
+
+	if (num_args) {
+		va_start(args, num_args);
+		bar_idx = va_arg(args, int);
+		va_end(args);
+	}
+
+	mr = libeth_find_mmio_region(&mmio_info->mmio_list, offset, bar_idx);
+	if (mr) {
+		pci_warn(pdev, "Mapping of BAR%u with offset %llu already exists\n",
+			 bar_idx, offset);
+		return true;
+	}
+
+	pa = pci_resource_start(pdev, bar_idx) + offset;
+	va = ioremap(pa, size);
+	if (!va) {
+		pci_err(pdev, "Failed to allocate BAR%u region\n", bar_idx);
+		return false;
+	}
+
+	mr = kvzalloc(sizeof(*mr), GFP_KERNEL);
+	if (!mr) {
+		iounmap(va);
+		return false;
+	}
+
+	mr->addr = va;
+	mr->offset = offset;
+	mr->size = size;
+	mr->bar_idx = bar_idx;
+
+	list_add_tail(&mr->list, &mmio_info->mmio_list);
+
+	return true;
+}
+EXPORT_SYMBOL_NS_GPL(__libeth_pci_map_mmio_region, "LIBETH_PCI");
+
+/**
+ * libeth_pci_unmap_all_mmio_regions - unmap all PCI device MMIO regions
+ * @mmio_info: contains list of MMIO regions to unmap
+ */
+void libeth_pci_unmap_all_mmio_regions(struct libeth_mmio_info *mmio_info)
+{
+	struct libeth_pci_mmio_region *mr, *tmp;
+
+	list_for_each_entry_safe(mr, tmp, &mmio_info->mmio_list, list) {
+		iounmap(mr->addr);
+		list_del(&mr->list);
+		kfree(mr);
+	}
+}
+EXPORT_SYMBOL_NS_GPL(libeth_pci_unmap_all_mmio_regions, "LIBETH_PCI");
+
+/**
+ * libeth_pci_init_dev - enable and reserve PCI regions of the device
+ * @pdev: PCI device information
+ *
+ * Return: %0 on success, -%errno on failure.
+ */
+int libeth_pci_init_dev(struct pci_dev *pdev)
+{
+	int err;
+
+	err = pci_enable_device(pdev);
+	if (err)
+		return err;
+
+	err = pci_request_mem_regions(pdev, pci_name(pdev));
+	if (err)
+		goto disable_dev;
+
+	err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	if (err)
+		goto rel_regions;
+
+	pci_set_master(pdev);
+
+	return 0;
+
+rel_regions:
+	pci_release_regions(pdev);
+disable_dev:
+	pci_disable_device(pdev);
+
+	return err;
+}
+EXPORT_SYMBOL_NS_GPL(libeth_pci_init_dev, "LIBETH_PCI");
+
+/**
+ * libeth_pci_deinit_dev - disable and release the PCI regions of the device
+ * @pdev: PCI device information
+ */
+void libeth_pci_deinit_dev(struct pci_dev *pdev)
+{
+	pci_disable_device(pdev);
+	pci_release_regions(pdev);
+}
+EXPORT_SYMBOL_NS_GPL(libeth_pci_deinit_dev, "LIBETH_PCI");
+
+MODULE_DESCRIPTION("Common Ethernet PCI library");
+MODULE_LICENSE("GPL");
diff --git a/include/net/libeth/pci.h b/include/net/libeth/pci.h
new file mode 100644
index 000000000000..6ae8032c2c8a
--- /dev/null
+++ b/include/net/libeth/pci.h
@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2025 Intel Corporation */
+
+#ifndef __LIBETH_PCI_H
+#define __LIBETH_PCI_H
+
+#include <linux/pci.h>
+
+/**
+ * struct libeth_pci_mmio_region - structure for MMIO region info
+ * @list: used to add a MMIO region to the list of MMIO regions in
+ *	  libeth_mmio_info
+ * @addr: virtual address of MMIO region start
+ * @offset: start offset of the MMIO region
+ * @size: size of the MMIO region
+ * @bar_idx: BAR index to which the MMIO region belongs to
+ */
+struct libeth_pci_mmio_region {
+	struct list_head	list;
+	void __iomem		*addr;
+	resource_size_t		offset;
+	resource_size_t		size;
+	u16			bar_idx;
+};
+
+/**
+ * struct libeth_mmio_info - contains list of MMIO regions
+ * @pdev: PCI device pointer
+ * @mmio_list: list of MMIO regions
+ */
+struct libeth_mmio_info {
+	struct pci_dev		*pdev;
+	struct list_head	mmio_list;
+};
+
+#define libeth_pci_map_mmio_region(mmio_info, offset, size, ...)	\
+	__libeth_pci_map_mmio_region(mmio_info, offset, size,		\
+				     COUNT_ARGS(__VA_ARGS__), ##__VA_ARGS__)
+
+#define libeth_pci_get_mmio_addr(mmio_info, offset, ...)		\
+	__libeth_pci_get_mmio_addr(mmio_info, offset,			\
+				   COUNT_ARGS(__VA_ARGS__), ##__VA_ARGS__)
+
+bool __libeth_pci_map_mmio_region(struct libeth_mmio_info *mmio_info,
+				  resource_size_t offset,
+				  resource_size_t size,
+				  int num_args, ...);
+void __iomem *__libeth_pci_get_mmio_addr(struct libeth_mmio_info *mmio_info,
+					 resource_size_t region_offset,
+					 int num_args, ...);
+void libeth_pci_unmap_all_mmio_regions(struct libeth_mmio_info *mmio_info);
+int libeth_pci_init_dev(struct pci_dev *pdev);
+void libeth_pci_deinit_dev(struct pci_dev *pdev);
+
+#endif /* __LIBETH_PCI_H */
-- 
2.47.0