[PATCH v9 02/13] PCI: Add devres helpers for iomap table

Philipp Stanner
2024-06-13T11:50:50Z

The pcim_iomap_devres.table administrated by pcim_iomap_table() has its
entries set and unset at several places throughout devres.c using manual
iterations which are effectively code duplications.

Add pcim_add_mapping_to_legacy_table() and
pcim_remove_mapping_from_legacy_table() helper functions and use them where
possible.

Link: https://lore.kernel.org/r/20240605081605.18769-4-pstanner@redhat.com
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
[bhelgaas: s/short bar/int bar/ for consistency]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/devres.c | 77 +++++++++++++++++++++++++++++++++-----------
1 file changed, 58 insertions(+), 19 deletions(-)

diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index f13edd4a3873..845d6fab0ce7 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -297,6 +297,52 @@ void __iomem * const *pcim_iomap_table(struct pci_dev *pdev)
}
EXPORT_SYMBOL(pcim_iomap_table);

+/*
+ * Fill the legacy mapping-table, so that drivers using the old API can
+ * still get a BAR's mapping address through pcim_iomap_table().
+ */
+static int pcim_add_mapping_to_legacy_table(struct pci_dev *pdev,
+ void __iomem *mapping, int bar)
+{
+ void __iomem **legacy_iomap_table;
+
+ if (bar >= PCI_STD_NUM_BARS)
+ return -EINVAL;
+
+ legacy_iomap_table = (void __iomem **)pcim_iomap_table(pdev);
+ if (!legacy_iomap_table)
+ return -ENOMEM;
+
+ /* The legacy mechanism doesn't allow for duplicate mappings. */
+ WARN_ON(legacy_iomap_table[bar]);
+
+ legacy_iomap_table[bar] = mapping;
+
+ return 0;
+}
+
+/*
+ * Remove a mapping. The table only contains whole-BAR mappings, so this will
+ * never interfere with ranged mappings.
+ */
+static void pcim_remove_mapping_from_legacy_table(struct pci_dev *pdev,
+ void __iomem *addr)
+{
+ int bar;
+ void __iomem **legacy_iomap_table;
+
+ legacy_iomap_table = (void __iomem **)pcim_iomap_table(pdev);
+ if (!legacy_iomap_table)
+ return;
+
+ for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
+ if (legacy_iomap_table[bar] == addr) {
+ legacy_iomap_table[bar] = NULL;
+ return;
+ }
+ }
+}
+
/**
* pcim_iomap - Managed pcim_iomap()
* @pdev: PCI device to iomap for
@@ -308,16 +354,20 @@ EXPORT_SYMBOL(pcim_iomap_table);
*/
void __iomem *pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen)
{
- void __iomem **tbl;
+ void __iomem *mapping;

- BUG_ON(bar >= PCIM_IOMAP_MAX);
-
- tbl = (void __iomem **)pcim_iomap_table(pdev);
- if (!tbl || tbl[bar]) /* duplicate mappings not allowed */
+ mapping = pci_iomap(pdev, bar, maxlen);
+ if (!mapping)
return NULL;

- tbl[bar] = pci_iomap(pdev, bar, maxlen);
- return tbl[bar];
+ if (pcim_add_mapping_to_legacy_table(pdev, mapping, bar) != 0)
+ goto err_table;
+
+ return mapping;
+
+err_table:
+ pci_iounmap(pdev, mapping);
+ return NULL;
}
EXPORT_SYMBOL(pcim_iomap);

@@ -330,20 +380,9 @@ EXPORT_SYMBOL(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);
+ pcim_remove_mapping_from_legacy_table(pdev, addr);
}
EXPORT_SYMBOL(pcim_iounmap);

--
2.45.0