PCI: dwc: Detect number of iATU windows

Currently the number of inbound and outbound iATU windows are determined
from DT properties. Unfortunately, there's 'num-viewport' for RC mode
and 'num-ib-windows' and 'num-ob-windows' for EP mode, yet the number of
windows is not mode dependent. Also, 'num-viewport' is not clear whether
that's inbound, outbound or both. We can probably assume it's outbound
windows as that's all RC mode uses.

However, using DT properties isn't really needed as the number of
regions can be detected at runtime by poking the iATU registers. The
basic algorithm is just writing a target address and reading back what
we wrote. In the unrolled ATU case, we have to take care not to go
past the mapped region.

With this, we can drop num_viewport in favor of num_ob_windows instead.

Link: https://lore.kernel.org/r/20201105211159.1814485-17-robh@kernel.org
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org

drivers/pci/controller/dwc/pcie-designware-ep.c

@@ -714,26 +714,6 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
 	ep->phys_base = res->start;
 	ep->addr_size = resource_size(res);
 
-	ret = of_property_read_u32(np, "num-ib-windows", &pci->num_ib_windows);
-	if (ret < 0) {
-		dev_err(dev, "Unable to read *num-ib-windows* property\n");
-		return ret;
-	}
-	if (pci->num_ib_windows > MAX_IATU_IN) {
-		dev_err(dev, "Invalid *num-ib-windows*\n");
-		return -EINVAL;
-	}
-
-	ret = of_property_read_u32(np, "num-ob-windows", &pci->num_ob_windows);
-	if (ret < 0) {
-		dev_err(dev, "Unable to read *num-ob-windows* property\n");
-		return ret;
-	}
-	if (pci->num_ob_windows > MAX_IATU_OUT) {
-		dev_err(dev, "Invalid *num-ob-windows*\n");
-		return -EINVAL;
-	}
-
 	ep->ib_window_map = devm_kcalloc(dev,
 					 BITS_TO_LONGS(pci->num_ib_windows),
 					 sizeof(long),

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -356,10 +356,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
 		}
 	}
 
-	ret = of_property_read_u32(np, "num-viewport", &pci->num_viewport);
-	if (ret)
-		pci->num_viewport = 2;
-
 	if (pci->link_gen < 1)
 		pci->link_gen = of_pci_get_max_link_speed(np);
 
@@ -598,7 +594,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 	dw_pcie_writel_dbi(pci, PCI_COMMAND, val);
 
 	/* Ensure all outbound windows are disabled so there are multiple matches */
-	for (i = 0; i < pci->num_viewport; i++)
+	for (i = 0; i < pci->num_ob_windows; i++)
 		dw_pcie_disable_atu(pci, i, DW_PCIE_REGION_OUTBOUND);
 
 	/*
@@ -615,7 +611,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 			if (resource_type(entry->res) != IORESOURCE_MEM)
 				continue;
 
-			if (pci->num_viewport <= ++atu_idx)
+			if (pci->num_ob_windows <= ++atu_idx)
 				break;
 
 			dw_pcie_prog_outbound_atu(pci, atu_idx,
@@ -625,7 +621,7 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 		}
 
 		if (pp->io_size) {
-			if (pci->num_viewport > ++atu_idx)
+			if (pci->num_ob_windows > ++atu_idx)
 				dw_pcie_prog_outbound_atu(pci, atu_idx,
 							  PCIE_ATU_TYPE_IO, pp->io_base,
 							  pp->io_bus_addr, pp->io_size);
@@ -633,9 +629,9 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
 				pci->io_cfg_atu_shared = true;
 		}
 
-		if (pci->num_viewport <= atu_idx)
+		if (pci->num_ob_windows <= atu_idx)
 			dev_warn(pci->dev, "Resources exceed number of ATU entries (%d)",
-				 pci->num_viewport);
+				 pci->num_ob_windows);
 	}
 
 	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);

drivers/pci/controller/dwc/pcie-designware.c

@@ -546,6 +546,70 @@ static u8 dw_pcie_iatu_unroll_enabled(struct dw_pcie *pci)
 	return 0;
 }
 
+static void dw_pcie_iatu_detect_regions_unroll(struct dw_pcie *pci)
+{
+	int max_region, i, ob = 0, ib = 0;
+	u32 val;
+
+	max_region = min((int)pci->atu_size / 512, 256);
+
+	for (i = 0; i < max_region; i++) {
+		dw_pcie_writel_ob_unroll(pci, i, PCIE_ATU_UNR_LOWER_TARGET,
+					0x11110000);
+
+		val = dw_pcie_readl_ob_unroll(pci, i, PCIE_ATU_UNR_LOWER_TARGET);
+		if (val == 0x11110000)
+			ob++;
+		else
+			break;
+	}
+
+	for (i = 0; i < max_region; i++) {
+		dw_pcie_writel_ib_unroll(pci, i, PCIE_ATU_UNR_LOWER_TARGET,
+					0x11110000);
+
+		val = dw_pcie_readl_ib_unroll(pci, i, PCIE_ATU_UNR_LOWER_TARGET);
+		if (val == 0x11110000)
+			ib++;
+		else
+			break;
+	}
+	pci->num_ib_windows = ib;
+	pci->num_ob_windows = ob;
+}
+
+static void dw_pcie_iatu_detect_regions(struct dw_pcie *pci)
+{
+	int max_region, i, ob = 0, ib = 0;
+	u32 val;
+
+	dw_pcie_writel_dbi(pci, PCIE_ATU_VIEWPORT, 0xFF);
+	max_region = dw_pcie_readl_dbi(pci, PCIE_ATU_VIEWPORT) + 1;
+
+	for (i = 0; i < max_region; i++) {
+		dw_pcie_writel_dbi(pci, PCIE_ATU_VIEWPORT, PCIE_ATU_REGION_OUTBOUND | i);
+		dw_pcie_writel_dbi(pci, PCIE_ATU_LOWER_TARGET, 0x11110000);
+		val = dw_pcie_readl_dbi(pci, PCIE_ATU_LOWER_TARGET);
+		if (val == 0x11110000)
+			ob++;
+		else
+			break;
+	}
+
+	for (i = 0; i < max_region; i++) {
+		dw_pcie_writel_dbi(pci, PCIE_ATU_VIEWPORT, PCIE_ATU_REGION_INBOUND | i);
+		dw_pcie_writel_dbi(pci, PCIE_ATU_LOWER_TARGET, 0x11110000);
+		val = dw_pcie_readl_dbi(pci, PCIE_ATU_LOWER_TARGET);
+		if (val == 0x11110000)
+			ib++;
+		else
+			break;
+	}
+
+	pci->num_ib_windows = ib;
+	pci->num_ob_windows = ob;
+}
+
 void dw_pcie_setup(struct dw_pcie *pci)
 {
 	u32 val;
@@ -556,15 +620,30 @@ void dw_pcie_setup(struct dw_pcie *pci)
 	if (pci->version >= 0x480A || (!pci->version &&
 				       dw_pcie_iatu_unroll_enabled(pci))) {
 		pci->iatu_unroll_enabled = true;
-		if (!pci->atu_base)
-			pci->atu_base =
-			    devm_platform_ioremap_resource_byname(pdev, "atu");
-		if (IS_ERR(pci->atu_base))
-			pci->atu_base = pci->dbi_base + DEFAULT_DBI_ATU_OFFSET;
-	}
-	dev_dbg(pci->dev, "iATU unroll: %s\n", pci->iatu_unroll_enabled ?
+		if (!pci->atu_base) {
+			struct resource *res =
+				platform_get_resource_byname(pdev, IORESOURCE_MEM, "atu");
+			if (res)
+				pci->atu_size = resource_size(res);
+			pci->atu_base = devm_ioremap_resource(dev, res);
+			if (IS_ERR(pci->atu_base))
+				pci->atu_base = pci->dbi_base + DEFAULT_DBI_ATU_OFFSET;
+		}
+
+		if (!pci->atu_size)
+			/* Pick a minimal default, enough for 8 in and 8 out windows */
+			pci->atu_size = SZ_4K;
+
+		dw_pcie_iatu_detect_regions_unroll(pci);
+	} else
+		dw_pcie_iatu_detect_regions(pci);
+
+	dev_info(pci->dev, "iATU unroll: %s\n", pci->iatu_unroll_enabled ?
 		"enabled" : "disabled");
 
+	dev_info(pci->dev, "Detected iATU regions: %u outbound, %u inbound",
+		 pci->num_ob_windows, pci->num_ib_windows);
+
 	if (pci->link_gen > 0)
 		dw_pcie_link_set_max_speed(pci, pci->link_gen);
 

drivers/pci/controller/dwc/pcie-designware.h

@@ -261,7 +261,7 @@ struct dw_pcie {
 	void __iomem		*dbi_base2;
 	/* Used when iatu_unroll_enabled is true */
 	void __iomem		*atu_base;
-	u32			num_viewport;
+	size_t			atu_size;
 	u32			num_ib_windows;
 	u32			num_ob_windows;
 	struct pcie_port	pp;

drivers/pci/controller/dwc/pcie-intel-gw.c

@@ -58,7 +58,6 @@
 
 struct intel_pcie_soc {
 	unsigned int	pcie_ver;
-	u32		num_viewport;
 };
 
 struct intel_pcie_port {
@@ -400,7 +399,6 @@ static const struct dw_pcie_host_ops intel_pcie_dw_ops = {
 
 static const struct intel_pcie_soc pcie_data = {
 	.pcie_ver =		0x520A,
-	.num_viewport =		3,
 };
 
 static int intel_pcie_probe(struct platform_device *pdev)
@@ -443,12 +441,6 @@ static int intel_pcie_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	/*
-	 * Intel PCIe doesn't configure IO region, so set viewport
-	 * to not perform IO region access.
-	 */
-	pci->num_viewport = data->num_viewport;
-
 	return 0;
 }
 

drivers/pci/controller/dwc/pcie-tegra194.c

@@ -2075,6 +2075,7 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev)
 	}
 	pcie->atu_dma_res = atu_dma_res;
 
+	pci->atu_size = resource_size(atu_dma_res);
 	pci->atu_base = devm_ioremap_resource(dev, atu_dma_res);
 	if (IS_ERR(pci->atu_base))
 		return PTR_ERR(pci->atu_base);