PCI: Add pci_rebar_size_supported() helper

Many callers of pci_rebar_get_possible_sizes() are interested in finding
out if a particular encoded BAR Size (PCIe r7.0, sec 7.8.6.3) is supported
by the particular BAR.

Add pci_rebar_size_supported() into PCI core to make it easy for the
drivers to determine if the BAR size is supported or not.

Use the new function in pci_resize_resource() and in
pci_iov_vf_bar_set_size().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patch.msgid.link/20251113180053.27944-6-ilpo.jarvinen@linux.intel.com

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 04b675e9096309fcb20e5ef6bcc568e82c1cb9ac..71ed85d38508451c23fc0f34345c9915e440e7dc 100644 (file)
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -1339,19 +1339,13 @@ EXPORT_SYMBOL_GPL(pci_sriov_configure_simple);
  */
 int pci_iov_vf_bar_set_size(struct pci_dev *dev, int resno, int size)
 {
-       u32 sizes;
-
        if (!pci_resource_is_iov(resno))
                return -EINVAL;
 
        if (pci_iov_is_memory_decoding_enabled(dev))
                return -EBUSY;
 
-       sizes = pci_rebar_get_possible_sizes(dev, resno);
-       if (!sizes)
-               return -ENOTSUPP;
-
-       if (!(sizes & BIT(size)))
+       if (!pci_rebar_size_supported(dev, resno, size))
                return -EINVAL;
 
        return pci_rebar_set_size(dev, resno, size);

diff --git a/drivers/pci/rebar.c b/drivers/pci/rebar.c
index 399660cb12fa4ac5bceb7a0c219ede25ad2ab92c..1c90b606b8d458222aa6aaf87d9fecb0633725f1 100644 (file)
--- a/drivers/pci/rebar.c
+++ b/drivers/pci/rebar.c
@@ -3,6 +3,7 @@
  * PCI Resizable BAR Extended Capability handling.
  */
 
+#include <linux/bits.h>
 #include <linux/bitfield.h>
 #include <linux/errno.h>
 #include <linux/export.h>
@@ -124,6 +125,23 @@ u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar)
 }
 EXPORT_SYMBOL(pci_rebar_get_possible_sizes);
 
+/**
+ * pci_rebar_size_supported - check if size is supported for BAR
+ * @pdev: PCI device
+ * @bar: BAR to check
+ * @size: encoded size as defined in the PCIe spec (0=1MB, 31=128TB)
+ *
+ * Return: %true if @bar is resizable and @size is supported, otherwise
+ *        %false.
+ */
+bool pci_rebar_size_supported(struct pci_dev *pdev, int bar, int size)
+{
+       u64 sizes = pci_rebar_get_possible_sizes(pdev, bar);
+
+       return BIT(size) & sizes;
+}
+EXPORT_SYMBOL_GPL(pci_rebar_size_supported);
+
 /**
  * pci_rebar_get_current_size - get the current size of a Resizable BAR
  * @pdev: PCI device
@@ -252,7 +270,6 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size,
 {
        struct pci_host_bridge *host;
        int old, ret;
-       u32 sizes;
 
        /* Check if we must preserve the firmware's resource assignment */
        host = pci_find_host_bridge(dev->bus);
@@ -262,11 +279,7 @@ int pci_resize_resource(struct pci_dev *dev, int resno, int size,
        if (pci_resize_is_memory_decoding_enabled(dev, resno))
                return -EBUSY;
 
-       sizes = pci_rebar_get_possible_sizes(dev, resno);
-       if (!sizes)
-               return -ENOTSUPP;
-
-       if (!(sizes & BIT(size)))
+       if (!pci_rebar_size_supported(dev, resno, size))
                return -EINVAL;
 
        old = pci_rebar_get_current_size(dev, resno);

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 33b27e0c4f3e7b93abfa8e34b62c84fb3abea7dc..0ef827cfaf0ca3237b98e6a5ab46cadb38cddfdb 100644 (file)
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1424,6 +1424,7 @@ int pci_release_resource(struct pci_dev *dev, int resno);
 int pci_rebar_bytes_to_size(u64 bytes);
 resource_size_t pci_rebar_size_to_bytes(int size);
 u32 pci_rebar_get_possible_sizes(struct pci_dev *pdev, int bar);
+bool pci_rebar_size_supported(struct pci_dev *pdev, int bar, int size);
 int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size,
                                     int exclude_bars);