[cip-dev] [RFC PATCH 4.19.y-cip 07/50] PCI: endpoint: Add helper to get first unreserved BAR

Lad Prabhakar
2020-10-12T14:20:29Z

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From: Kishon Vijay Abraham I <kishon@ti.com>

commit 1e9efe6c9976552e88c6e6feaca3a78b8cf5aaf6 upstream.

Add a helper function pci_epc_get_first_free_bar() to get the first
unreserved BAR that can be used for endpoint function.

Tested-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
drivers/pci/endpoint/pci-epc-core.c | 23 +++++++++++++++++++++++
include/linux/pci-epc.h | 2 ++
2 files changed, 25 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 5a099479d9ab..e4712a0f249c 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -83,6 +83,29 @@ struct pci_epc *pci_epc_get(const char *epc_name)
}
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
+ * 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)
+{
+ int free_bar;
+
+ if (!epc_features)
+ return 0;
+
+ free_bar = ffz(epc_features->reserved_bar);
+ if (free_bar > 5)
+ return 0;
+
+ return free_bar;
+}
+EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
+
/**
* pci_epc_get_features() - get the features supported by EPC
* @epc: the features supported by *this* EPC device will be returned
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index fcd5e5047546..dcaecf715b1c 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -183,6 +183,8 @@ int pci_epc_start(struct pci_epc *epc);
void pci_epc_stop(struct pci_epc *epc);
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);
struct pci_epc *pci_epc_get(const char *epc_name);
void pci_epc_put(struct pci_epc *epc);

--
2.17.1

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