PCI: endpoint: Clean up hardware description for BARs

The hardware description for BARs is scattered in many different variables
in pci_epc_features. Some of these things are mutually exclusive, so it
can create confusion over which variable that has precedence over another.

Improve the situation by creating a struct pci_epc_bar_desc, and a new
enum pci_epc_bar_type, and convert the endpoint controller drivers to use
this more well defined format.

Additionally, some endpoint controller drivers mark the BAR succeeding a
"64-bit only BAR" as reserved, while some do not. By definition, a 64-bit
BAR uses the succeeding BAR for the upper 32-bits, so an EPF driver cannot
use a BAR succeeding a 64-bit BAR. Ensure that all endpoint controller
drivers are uniform, and actually describe a reserved BAR as reserved.

Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Kishon Vijay Abraham I <kishon@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20240216134524.1142149-2-cassel@kernel.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

5 files changed, 31 insertions, 30 deletions

diff --git a/drivers/pci/endpoint/functions/pci-epf-ntb.c b/drivers/pci/endpoint/functions/pci-epf-ntb.c
index 43cd309ce22f..e01a98e74d21 100644
--- a/drivers/pci/endpoint/functions/pci-epf-ntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-ntb.c
@@ -1012,13 +1012,13 @@ static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb,
 
 	epc_features = ntb_epc->epc_features;
 	barno = ntb_epc->epf_ntb_bar[BAR_CONFIG];
-	size = epc_features->bar_fixed_size[barno];
+	size = epc_features->bar[barno].fixed_size;
 	align = epc_features->align;
 
 	peer_ntb_epc = ntb->epc[!type];
 	peer_epc_features = peer_ntb_epc->epc_features;
 	peer_barno = ntb_epc->epf_ntb_bar[BAR_PEER_SPAD];
-	peer_size = peer_epc_features->bar_fixed_size[peer_barno];
+	peer_size = peer_epc_features->bar[peer_barno].fixed_size;
 
 	/* Check if epc_features is populated incorrectly */
 	if ((!IS_ALIGNED(size, align)))
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 981894e40681..cd4ffb39dcdc 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -729,7 +729,7 @@ static int pci_epf_test_set_bar(struct pci_epf *epf)
 		 */
 		add = (epf_bar->flags & PCI_BASE_ADDRESS_MEM_TYPE_64) ? 2 : 1;
 
-		if (!!(epc_features->reserved_bar & (1 << bar)))
+		if (epc_features->bar[bar].type == BAR_RESERVED)
 			continue;
 
 		ret = pci_epc_set_bar(epc, epf->func_no, epf->vfunc_no,
@@ -856,7 +856,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
 		if (bar == test_reg_bar)
 			continue;
 
-		if (!!(epc_features->reserved_bar & (1 << bar)))
+		if (epc_features->bar[bar].type == BAR_RESERVED)
 			continue;
 
 		base = pci_epf_alloc_space(epf, bar_size[bar], bar,
@@ -874,13 +874,11 @@ static void pci_epf_configure_bar(struct pci_epf *epf,
 				  const struct pci_epc_features *epc_features)
 {
 	struct pci_epf_bar *epf_bar;
-	bool bar_fixed_64bit;
 	int i;
 
 	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
 		epf_bar = &epf->bar[i];
-		bar_fixed_64bit = !!(epc_features->bar_fixed_64bit & (1 << i));
-		if (bar_fixed_64bit)
+		if (epc_features->bar[i].only_64bit)
 			epf_bar->flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;
 	}
 }
diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 0675929fc529..8e779eecd62d 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -422,7 +422,7 @@ static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb)
 								epf->func_no,
 								epf->vfunc_no);
 	barno = ntb->epf_ntb_bar[BAR_CONFIG];
-	size = epc_features->bar_fixed_size[barno];
+	size = epc_features->bar[barno].fixed_size;
 	align = epc_features->align;
 
 	if ((!IS_ALIGNED(size, align)))
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index dcd4e66430c1..7fe8f4336765 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -87,7 +87,7 @@ EXPORT_SYMBOL_GPL(pci_epc_get);
  * @epc_features: pci_epc_features structure that holds the reserved bar bitmap
  *
  * Invoke to get the first unreserved BAR that can be used by the endpoint
- * function. For any incorrect value in reserved_bar return '0'.
+ * function.
  */
 enum pci_barno
 pci_epc_get_first_free_bar(const struct pci_epc_features *epc_features)
@@ -102,32 +102,34 @@ EXPORT_SYMBOL_GPL(pci_epc_get_first_free_bar);
  * @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'.
+ * for endpoint function.
  */
 enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features
 					 *epc_features, enum pci_barno bar)
 {
-	unsigned long free_bar;
+	int i;
 
 	if (!epc_features)
 		return BAR_0;
 
 	/* If 'bar - 1' is a 64-bit BAR, move to the next BAR */
-	if ((epc_features->bar_fixed_64bit << 1) & 1 << bar)
+	if (bar > 0 && epc_features->bar[bar - 1].only_64bit)
 		bar++;
 
-	/* Find if the reserved BAR is also a 64-bit BAR */
-	free_bar = epc_features->reserved_bar & epc_features->bar_fixed_64bit;
-
-	/* Set the adjacent bit if the reserved BAR is also a 64-bit BAR */
-	free_bar <<= 1;
-	free_bar |= epc_features->reserved_bar;
-
-	free_bar = find_next_zero_bit(&free_bar, 6, bar);
-	if (free_bar > 5)
-		return NO_BAR;
+	for (i = bar; i < PCI_STD_NUM_BARS; i++) {
+		/* If the BAR is not reserved, return it. */
+		if (epc_features->bar[i].type != BAR_RESERVED)
+			return i;
+
+		/*
+		 * If the BAR is reserved, and marked as 64-bit only, then the
+		 * succeeding BAR is also reserved.
+		 */
+		if (epc_features->bar[i].only_64bit)
+			i++;
+	}
 
-	return free_bar;
+	return NO_BAR;
 }
 EXPORT_SYMBOL_GPL(pci_epc_get_next_free_bar);
 
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index f2b4d34454c4..0a28a0b0911b 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -260,7 +260,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 			  const struct pci_epc_features *epc_features,
 			  enum pci_epc_interface_type type)
 {
-	u64 bar_fixed_size = epc_features->bar_fixed_size[bar];
+	u64 bar_fixed_size = epc_features->bar[bar].fixed_size;
 	size_t align = epc_features->align;
 	struct pci_epf_bar *epf_bar;
 	dma_addr_t phys_addr;
@@ -271,13 +271,14 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
 	if (size < 128)
 		size = 128;
 
-	if (bar_fixed_size && size > bar_fixed_size) {
-		dev_err(&epf->dev, "requested BAR size is larger than fixed size\n");
-		return NULL;
-	}
-
-	if (bar_fixed_size)
+	if (epc_features->bar[bar].type == BAR_FIXED && bar_fixed_size) {
+		if (size > bar_fixed_size) {
+			dev_err(&epf->dev,
+				"requested BAR size is larger than fixed size\n");
+			return NULL;
+		}
 		size = bar_fixed_size;
+	}
 
 	if (align)
 		size = ALIGN(size, align);