[PATCH v2 03/14] PCI: endpoint: Add helper API to get the 'next' unreserved BAR

Kishon Vijay Abraham I
2020-06-11T13:06:10Z

Add an API to get the next unreserved BAR starting from a given BAR
number that can be used by the endpoint function.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
drivers/pci/endpoint/pci-epc-core.c | 26 ++++++++++++++++++++++----
include/linux/pci-epc.h | 2 ++
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index b9f4d3fe2f6f..ba05e616a407 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -87,17 +87,36 @@ EXPORT_SYMBOL_GPL(pci_epc_get);
* pci_epc_get_first_free_bar() - helper to get first unreserved BAR
* @epc_features: pci_epc_features structure that holds the reserved bar bitmap
*
- * Invoke to get the first unreserved BAR that can be used for endpoint
+ * Invoke to get the first unreserved BAR that can be used by the endpoint
* function. For any incorrect value in reserved_bar return '0'.
*/
unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
*epc_features)
+{
+ return pci_epc_get_next_free_bar(epc_features, BAR_0);
+}
+EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
+
+/**
+ * pci_epc_get_next_free_bar() - helper to get unreserved BAR starting from @bar
+ * @epc_features: pci_epc_features structure that holds the reserved bar bitmap
+ * @bar: the starting BAR number from where unreserved BAR should be searched
+ *
+ * Invoke to get the next unreserved BAR starting from @bar that can be used
+ * for endpoint function. For any incorrect value in reserved_bar return '0'.
+ */
+unsigned int pci_epc_get_next_free_bar(const struct pci_epc_features
+ *epc_features, enum pci_barno bar)
{
unsigned long free_bar;

if (!epc_features)
return 0;

+ /* If 'bar - 1' is a 64-bit BAR, move to the next BAR */
+ if ((epc_features->bar_fixed_64bit << 1) & 1 << bar)
+ bar++;
+
/* Find if the reserved BAR is also a 64-bit BAR */
free_bar = epc_features->reserved_bar & epc_features->bar_fixed_64bit;

@@ -105,14 +124,13 @@ unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
free_bar <<= 1;
free_bar |= epc_features->reserved_bar;

- /* Now find the free BAR */
- free_bar = ffz(free_bar);
+ free_bar = find_next_zero_bit(&free_bar, 6, bar);
if (free_bar > 5)
return 0;

return free_bar;
}
-EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
+EXPORT_SYMBOL_GPL(pci_epc_get_next_free_bar);

/**
* pci_epc_get_features() - get the features supported by EPC
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index cc66bec8be90..cfe9b427e6b7 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -203,6 +203,8 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,
u8 func_no);
unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
*epc_features);
+unsigned int pci_epc_get_next_free_bar(const struct pci_epc_features
+ *epc_features, enum pci_barno bar);
struct pci_epc *pci_epc_get(const char *epc_name);
void pci_epc_put(struct pci_epc *epc);

--
2.17.1