Commit fa8fef0e authored by Kishon Vijay Abraham I's avatar Kishon Vijay Abraham I Committed by Bjorn Helgaas
Browse files

PCI: endpoint: Add helper API to get the 'next' unreserved BAR 

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

Link: https://lore.kernel.org/r/20210201195809.7342-4-kishon@ti.com


Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 959a48d0

drivers/pci/endpoint/pci-epc-core.c

+22 −4
Original line number Diff line number Diff line
@@ -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

include/linux/pci-epc.h

+2 −0
Original line number Diff line number Diff line
@@ -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);