PCI: Move PCI-specific devres code to drivers/pci/

The pcim_*() functions in lib/devres.c are guarded by an #ifdef CONFIG_PCI
and, thus, don't belong to this file. They are only ever used for PCI and
are not generic infrastructure.

Move all pcim_*() functions in lib/devres.c to drivers/pci/devres.c.
Adjust the Makefile.

Add drivers/pci/devres.c to Documentation.

Link: https://lore.kernel.org/r/20240131090023.12331-4-pstanner@redhat.com
Suggested-by: Danilo Krummrich <dakr@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 207 insertions, 0 deletions

diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
new file mode 100644
index 000000000000..a3fd0d65cef1
--- /dev/null
+++ b/drivers/pci/devres.c
@@ -0,0 +1,207 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/pci.h>
+#include "pci.h"
+
+/*
+ * PCI iomap devres
+ */
+#define PCIM_IOMAP_MAX	PCI_STD_NUM_BARS
+
+struct pcim_iomap_devres {
+	void __iomem *table[PCIM_IOMAP_MAX];
+};
+
+static void pcim_iomap_release(struct device *gendev, void *res)
+{
+	struct pci_dev *dev = to_pci_dev(gendev);
+	struct pcim_iomap_devres *this = res;
+	int i;
+
+	for (i = 0; i < PCIM_IOMAP_MAX; i++)
+		if (this->table[i])
+			pci_iounmap(dev, this->table[i]);
+}
+
+/**
+ * pcim_iomap_table - access iomap allocation table
+ * @pdev: PCI device to access iomap table for
+ *
+ * Access iomap allocation table for @dev.  If iomap table doesn't
+ * exist and @pdev is managed, it will be allocated.  All iomaps
+ * recorded in the iomap table are automatically unmapped on driver
+ * detach.
+ *
+ * This function might sleep when the table is first allocated but can
+ * be safely called without context and guaranteed to succeed once
+ * allocated.
+ */
+void __iomem * const *pcim_iomap_table(struct pci_dev *pdev)
+{
+	struct pcim_iomap_devres *dr, *new_dr;
+
+	dr = devres_find(&pdev->dev, pcim_iomap_release, NULL, NULL);
+	if (dr)
+		return dr->table;
+
+	new_dr = devres_alloc_node(pcim_iomap_release, sizeof(*new_dr), GFP_KERNEL,
+				   dev_to_node(&pdev->dev));
+	if (!new_dr)
+		return NULL;
+	dr = devres_get(&pdev->dev, new_dr, NULL, NULL);
+	return dr->table;
+}
+EXPORT_SYMBOL(pcim_iomap_table);
+
+/**
+ * pcim_iomap - Managed pcim_iomap()
+ * @pdev: PCI device to iomap for
+ * @bar: BAR to iomap
+ * @maxlen: Maximum length of iomap
+ *
+ * Managed pci_iomap().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen)
+{
+	void __iomem **tbl;
+
+	BUG_ON(bar >= PCIM_IOMAP_MAX);
+
+	tbl = (void __iomem **)pcim_iomap_table(pdev);
+	if (!tbl || tbl[bar])	/* duplicate mappings not allowed */
+		return NULL;
+
+	tbl[bar] = pci_iomap(pdev, bar, maxlen);
+	return tbl[bar];
+}
+EXPORT_SYMBOL(pcim_iomap);
+
+/**
+ * pcim_iounmap - Managed pci_iounmap()
+ * @pdev: PCI device to iounmap for
+ * @addr: Address to unmap
+ *
+ * Managed pci_iounmap().  @addr must have been mapped using pcim_iomap().
+ */
+void pcim_iounmap(struct pci_dev *pdev, void __iomem *addr)
+{
+	void __iomem **tbl;
+	int i;
+
+	pci_iounmap(pdev, addr);
+
+	tbl = (void __iomem **)pcim_iomap_table(pdev);
+	BUG_ON(!tbl);
+
+	for (i = 0; i < PCIM_IOMAP_MAX; i++)
+		if (tbl[i] == addr) {
+			tbl[i] = NULL;
+			return;
+		}
+	WARN_ON(1);
+}
+EXPORT_SYMBOL(pcim_iounmap);
+
+/**
+ * pcim_iomap_regions - Request and iomap PCI BARs
+ * @pdev: PCI device to map IO resources for
+ * @mask: Mask of BARs to request and iomap
+ * @name: Name used when requesting regions
+ *
+ * Request and iomap regions specified by @mask.
+ */
+int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
+{
+	void __iomem * const *iomap;
+	int i, rc;
+
+	iomap = pcim_iomap_table(pdev);
+	if (!iomap)
+		return -ENOMEM;
+
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
+		unsigned long len;
+
+		if (!(mask & (1 << i)))
+			continue;
+
+		rc = -EINVAL;
+		len = pci_resource_len(pdev, i);
+		if (!len)
+			goto err_inval;
+
+		rc = pci_request_region(pdev, i, name);
+		if (rc)
+			goto err_inval;
+
+		rc = -ENOMEM;
+		if (!pcim_iomap(pdev, i, 0))
+			goto err_region;
+	}
+
+	return 0;
+
+ err_region:
+	pci_release_region(pdev, i);
+ err_inval:
+	while (--i >= 0) {
+		if (!(mask & (1 << i)))
+			continue;
+		pcim_iounmap(pdev, iomap[i]);
+		pci_release_region(pdev, i);
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL(pcim_iomap_regions);
+
+/**
+ * pcim_iomap_regions_request_all - Request all BARs and iomap specified ones
+ * @pdev: PCI device to map IO resources for
+ * @mask: Mask of BARs to iomap
+ * @name: Name used when requesting regions
+ *
+ * Request all PCI BARs and iomap regions specified by @mask.
+ */
+int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
+				   const char *name)
+{
+	int request_mask = ((1 << 6) - 1) & ~mask;
+	int rc;
+
+	rc = pci_request_selected_regions(pdev, request_mask, name);
+	if (rc)
+		return rc;
+
+	rc = pcim_iomap_regions(pdev, mask, name);
+	if (rc)
+		pci_release_selected_regions(pdev, request_mask);
+	return rc;
+}
+EXPORT_SYMBOL(pcim_iomap_regions_request_all);
+
+/**
+ * pcim_iounmap_regions - Unmap and release PCI BARs
+ * @pdev: PCI device to map IO resources for
+ * @mask: Mask of BARs to unmap and release
+ *
+ * Unmap and release regions specified by @mask.
+ */
+void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
+{
+	void __iomem * const *iomap;
+	int i;
+
+	iomap = pcim_iomap_table(pdev);
+	if (!iomap)
+		return;
+
+	for (i = 0; i < PCIM_IOMAP_MAX; i++) {
+		if (!(mask & (1 << i)))
+			continue;
+
+		pcim_iounmap(pdev, iomap[i]);
+		pci_release_region(pdev, i);
+	}
+}
+EXPORT_SYMBOL(pcim_iounmap_regions);