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>

14 files changed, 108 insertions, 58 deletions

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index dc2c036ab28c..47a9a96484ed 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1081,7 +1081,8 @@ static const struct pci_epc_features imx8m_pcie_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
 	.msix_capable = false,
-	.reserved_bar = 1 << BAR_1 | 1 << BAR_3,
+	.bar[BAR_1] = { .type = BAR_RESERVED, },
+	.bar[BAR_3] = { .type = BAR_RESERVED, },
 	.align = SZ_64K,
 };
 
diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c
index c0c62533a3f1..b2b93b4fa82d 100644
--- a/drivers/pci/controller/dwc/pci-keystone.c
+++ b/drivers/pci/controller/dwc/pci-keystone.c
@@ -924,12 +924,12 @@ static const struct pci_epc_features ks_pcie_am654_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
 	.msix_capable = true,
-	.reserved_bar = 1 << BAR_0 | 1 << BAR_1,
-	.bar_fixed_64bit = 1 << BAR_0,
-	.bar_fixed_size[2] = SZ_1M,
-	.bar_fixed_size[3] = SZ_64K,
-	.bar_fixed_size[4] = 256,
-	.bar_fixed_size[5] = SZ_1M,
+	.bar[BAR_0] = { .type = BAR_RESERVED, .only_64bit = true, },
+	.bar[BAR_1] = { .type = BAR_RESERVED, },
+	.bar[BAR_2] = { .type = BAR_FIXED, .fixed_size = SZ_1M, },
+	.bar[BAR_3] = { .type = BAR_FIXED, .fixed_size = SZ_64K, },
+	.bar[BAR_4] = { .type = BAR_FIXED, .fixed_size = 256, },
+	.bar[BAR_5] = { .type = BAR_FIXED, .fixed_size = SZ_1M, },
 	.align = SZ_1M,
 };
 
diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c
index 2e398494e7c0..1f6ee1460ec2 100644
--- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
+++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
@@ -250,7 +250,10 @@ static int __init ls_pcie_ep_probe(struct platform_device *pdev)
 	pci->dev = dev;
 	pci->ops = pcie->drvdata->dw_pcie_ops;
 
-	ls_epc->bar_fixed_64bit = (1 << BAR_2) | (1 << BAR_4);
+	ls_epc->bar[BAR_2].only_64bit = true;
+	ls_epc->bar[BAR_3].type = BAR_RESERVED;
+	ls_epc->bar[BAR_4].only_64bit = true;
+	ls_epc->bar[BAR_5].type = BAR_RESERVED;
 	ls_epc->linkup_notifier = true;
 
 	pcie->pci = pci;
diff --git a/drivers/pci/controller/dwc/pcie-keembay.c b/drivers/pci/controller/dwc/pcie-keembay.c
index 208d3b0ba196..5e8e54f597dd 100644
--- a/drivers/pci/controller/dwc/pcie-keembay.c
+++ b/drivers/pci/controller/dwc/pcie-keembay.c
@@ -312,8 +312,12 @@ static const struct pci_epc_features keembay_pcie_epc_features = {
 	.linkup_notifier	= false,
 	.msi_capable		= true,
 	.msix_capable		= true,
-	.reserved_bar		= BIT(BAR_1) | BIT(BAR_3) | BIT(BAR_5),
-	.bar_fixed_64bit	= BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4),
+	.bar[BAR_0]		= { .only_64bit = true, },
+	.bar[BAR_1]		= { .type = BAR_RESERVED, },
+	.bar[BAR_2]		= { .only_64bit = true, },
+	.bar[BAR_3]		= { .type = BAR_RESERVED, },
+	.bar[BAR_4]		= { .only_64bit = true, },
+	.bar[BAR_5]		= { .type = BAR_RESERVED, },
 	.align			= SZ_16K,
 };
 
diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
index e9166619b1f9..0be760ed420b 100644
--- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
+++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
@@ -383,7 +383,9 @@ static const struct pci_epc_features rcar_gen4_pcie_epc_features = {
 	.linkup_notifier = false,
 	.msi_capable = true,
 	.msix_capable = false,
-	.reserved_bar = 1 << BAR_1 | 1 << BAR_3 | 1 << BAR_5,
+	.bar[BAR_1] = { .type = BAR_RESERVED, },
+	.bar[BAR_3] = { .type = BAR_RESERVED, },
+	.bar[BAR_5] = { .type = BAR_RESERVED, },
 	.align = SZ_1M,
 };
 
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 7afa9e9aabe2..1f7b662cb8e1 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -2007,9 +2007,13 @@ static const struct pci_epc_features tegra_pcie_epc_features = {
 	.core_init_notifier = true,
 	.msi_capable = false,
 	.msix_capable = false,
-	.reserved_bar = 1 << BAR_2 | 1 << BAR_3 | 1 << BAR_4 | 1 << BAR_5,
-	.bar_fixed_64bit = 1 << BAR_0,
-	.bar_fixed_size[0] = SZ_1M,
+	.bar[BAR_0] = { .type = BAR_FIXED, .fixed_size = SZ_1M,
+			.only_64bit = true, },
+	.bar[BAR_1] = { .type = BAR_RESERVED, },
+	.bar[BAR_2] = { .type = BAR_RESERVED, },
+	.bar[BAR_3] = { .type = BAR_RESERVED, },
+	.bar[BAR_4] = { .type = BAR_RESERVED, },
+	.bar[BAR_5] = { .type = BAR_RESERVED, },
 };
 
 static const struct pci_epc_features*
diff --git a/drivers/pci/controller/dwc/pcie-uniphier-ep.c b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
index 3fced0d3e851..265f65fc673f 100644
--- a/drivers/pci/controller/dwc/pcie-uniphier-ep.c
+++ b/drivers/pci/controller/dwc/pcie-uniphier-ep.c
@@ -411,8 +411,12 @@ static const struct uniphier_pcie_ep_soc_data uniphier_pro5_data = {
 		.msi_capable = true,
 		.msix_capable = false,
 		.align = 1 << 16,
-		.bar_fixed_64bit = BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4),
-		.reserved_bar =  BIT(BAR_4),
+		.bar[BAR_0] = { .only_64bit = true, },
+		.bar[BAR_1] = { .type = BAR_RESERVED, },
+		.bar[BAR_2] = { .only_64bit = true, },
+		.bar[BAR_3] = { .type = BAR_RESERVED, },
+		.bar[BAR_4] = { .type = BAR_RESERVED, .only_64bit = true, },
+		.bar[BAR_5] = { .type = BAR_RESERVED, },
 	},
 };
 
@@ -425,7 +429,12 @@ static const struct uniphier_pcie_ep_soc_data uniphier_nx1_data = {
 		.msi_capable = true,
 		.msix_capable = false,
 		.align = 1 << 12,
-		.bar_fixed_64bit = BIT(BAR_0) | BIT(BAR_2) | BIT(BAR_4),
+		.bar[BAR_0] = { .only_64bit = true, },
+		.bar[BAR_1] = { .type = BAR_RESERVED, },
+		.bar[BAR_2] = { .only_64bit = true, },
+		.bar[BAR_3] = { .type = BAR_RESERVED, },
+		.bar[BAR_4] = { .only_64bit = true, },
+		.bar[BAR_5] = { .type = BAR_RESERVED, },
 	},
 };
 
diff --git a/drivers/pci/controller/pcie-rcar-ep.c b/drivers/pci/controller/pcie-rcar-ep.c
index e6909271def7..05967c6c0b42 100644
--- a/drivers/pci/controller/pcie-rcar-ep.c
+++ b/drivers/pci/controller/pcie-rcar-ep.c
@@ -440,11 +440,15 @@ static const struct pci_epc_features rcar_pcie_epc_features = {
 	.msi_capable = true,
 	.msix_capable = false,
 	/* use 64-bit BARs so mark BAR[1,3,5] as reserved */
-	.reserved_bar = 1 << BAR_1 | 1 << BAR_3 | 1 << BAR_5,
-	.bar_fixed_64bit = 1 << BAR_0 | 1 << BAR_2 | 1 << BAR_4,
-	.bar_fixed_size[0] = 128,
-	.bar_fixed_size[2] = 256,
-	.bar_fixed_size[4] = 256,
+	.bar[BAR_0] = { .type = BAR_FIXED, .fixed_size = 128,
+			.only_64bit = true, },
+	.bar[BAR_1] = { .type = BAR_RESERVED, },
+	.bar[BAR_2] = { .type = BAR_FIXED, .fixed_size = 256,
+			.only_64bit = true, },
+	.bar[BAR_3] = { .type = BAR_RESERVED, },
+	.bar[BAR_4] = { .type = BAR_FIXED, .fixed_size = 256,
+			.only_64bit = true, },
+	.bar[BAR_5] = { .type = BAR_RESERVED, },
 };
 
 static const struct pci_epc_features*
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);
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 40ea18f5aa02..4ccb4f4f3883 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -146,15 +146,39 @@ struct pci_epc {
 };
 
 /**
+ * @BAR_PROGRAMMABLE: The BAR mask can be configured by the EPC.
+ * @BAR_FIXED: The BAR mask is fixed by the hardware.
+ * @BAR_RESERVED: The BAR should not be touched by an EPF driver.
+ */
+enum pci_epc_bar_type {
+	BAR_PROGRAMMABLE = 0,
+	BAR_FIXED,
+	BAR_RESERVED,
+};
+
+/**
+ * struct pci_epc_bar_desc - hardware description for a BAR
+ * @type: the type of the BAR
+ * @fixed_size: the fixed size, only applicable if type is BAR_FIXED_MASK.
+ * @only_64bit: if true, an EPF driver is not allowed to choose if this BAR
+ *		should be configured as 32-bit or 64-bit, the EPF driver must
+ *		configure this BAR as 64-bit. Additionally, the BAR succeeding
+ *		this BAR must be set to type BAR_RESERVED.
+ */
+struct pci_epc_bar_desc {
+	enum pci_epc_bar_type type;
+	u64 fixed_size;
+	bool only_64bit;
+};
+
+/**
  * struct pci_epc_features - features supported by a EPC device per function
  * @linkup_notifier: indicate if the EPC device can notify EPF driver on link up
  * @core_init_notifier: indicate cores that can notify about their availability
  *			for initialization
  * @msi_capable: indicate if the endpoint function has MSI capability
  * @msix_capable: indicate if the endpoint function has MSI-X capability
- * @reserved_bar: bitmap to indicate reserved BAR unavailable to function driver
- * @bar_fixed_64bit: bitmap to indicate fixed 64bit BARs
- * @bar_fixed_size: Array specifying the size supported by each BAR
+ * @bar: array specifying the hardware description for each BAR
  * @align: alignment size required for BAR buffer allocation
  */
 struct pci_epc_features {
@@ -162,9 +186,7 @@ struct pci_epc_features {
 	unsigned int	core_init_notifier : 1;
 	unsigned int	msi_capable : 1;
 	unsigned int	msix_capable : 1;
-	u8	reserved_bar;
-	u8	bar_fixed_64bit;
-	u64	bar_fixed_size[PCI_STD_NUM_BARS];
+	struct	pci_epc_bar_desc bar[PCI_STD_NUM_BARS];
 	size_t	align;
 };