PCI: faraday: Convert IRQ masking to raw PCI config accessors

Current ftpci100 driver host bridge controller driver requires struct
pci_bus to be created in order to mask and clear IRQs using standard PCI
bus config accessors.

This struct pci_bus dependency is fictitious and burdens the driver with
unneeded constraints (eg to use separate APIs to create and scan the root
bus).

Add PCI raw config space accessors to PCIe ftpci100 driver and remove the
fictitious struct pci_bus dependency.
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: folded in raw PCI read accessor from
http://lkml.kernel.org/r/20170621162651.25315-1-linus.walleij@linaro.org
The clock piece of the above posting goes with the separate "Add clock
handling" patch.]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pci/host/pci-ftpci100.c

@@ -178,12 +178,11 @@ static int faraday_res_to_memcfg(resource_size_t mem_base,
 	return 0;
 }
 
-static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
-				   int config, int size, u32 *value)
+static int faraday_raw_pci_read_config(struct faraday_pci *p, int bus_number,
+				       unsigned int fn, int config, int size,
+				       u32 *value)
 {
-	struct faraday_pci *p = bus->sysdata;
-
-	writel(PCI_CONF_BUS(bus->number) |
+	writel(PCI_CONF_BUS(bus_number) |
 			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
 			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
 			PCI_CONF_WHERE(config) |
@@ -197,24 +196,28 @@ static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
 	else if (size == 2)
 		*value = (*value >> (8 * (config & 3))) & 0xFFFF;
 
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int faraday_pci_read_config(struct pci_bus *bus, unsigned int fn,
+				   int config, int size, u32 *value)
+{
+	struct faraday_pci *p = bus->sysdata;
+
 	dev_dbg(&bus->dev,
 		"[read]  slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
 		PCI_SLOT(fn), PCI_FUNC(fn), config, size, *value);
 
-	return PCIBIOS_SUCCESSFUL;
+	return faraday_raw_pci_read_config(p, bus->number, fn, config, size, value);
 }
 
-static int faraday_pci_write_config(struct pci_bus *bus, unsigned int fn,
-				    int config, int size, u32 value)
+static int faraday_raw_pci_write_config(struct faraday_pci *p, int bus_number,
+					 unsigned int fn, int config, int size,
+					 u32 value)
 {
-	struct faraday_pci *p = bus->sysdata;
 	int ret = PCIBIOS_SUCCESSFUL;
 
-	dev_dbg(&bus->dev,
-		"[write] slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
-		PCI_SLOT(fn), PCI_FUNC(fn), config, size, value);
-
-	writel(PCI_CONF_BUS(bus->number) |
+	writel(PCI_CONF_BUS(bus_number) |
 			PCI_CONF_DEVICE(PCI_SLOT(fn)) |
 			PCI_CONF_FUNCTION(PCI_FUNC(fn)) |
 			PCI_CONF_WHERE(config) |
@@ -238,6 +241,19 @@ static int faraday_pci_write_config(struct pci_bus *bus, unsigned int fn,
 	return ret;
 }
 
+static int faraday_pci_write_config(struct pci_bus *bus, unsigned int fn,
+				    int config, int size, u32 value)
+{
+	struct faraday_pci *p = bus->sysdata;
+
+	dev_dbg(&bus->dev,
+		"[write] slt: %.2d, fnc: %d, cnf: 0x%.2X, val (%d bytes): 0x%.8X\n",
+		PCI_SLOT(fn), PCI_FUNC(fn), config, size, value);
+
+	return faraday_raw_pci_write_config(p, bus->number, fn, config, size,
+					    value);
+}
+
 static struct pci_ops faraday_pci_ops = {
 	.read	= faraday_pci_read_config,
 	.write	= faraday_pci_write_config,
@@ -248,10 +264,10 @@ static void faraday_pci_ack_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTSTS_SHIFT);
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_mask_irq(struct irq_data *d)
@@ -259,10 +275,10 @@ static void faraday_pci_mask_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~((0xF << PCI_CTRL2_INTSTS_SHIFT)
 		 | BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT));
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_unmask_irq(struct irq_data *d)
@@ -270,10 +286,10 @@ static void faraday_pci_unmask_irq(struct irq_data *d)
 	struct faraday_pci *p = irq_data_get_irq_chip_data(d);
 	unsigned int reg;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	reg &= ~(0xF << PCI_CTRL2_INTSTS_SHIFT);
 	reg |= BIT(irqd_to_hwirq(d) + PCI_CTRL2_INTMASK_SHIFT);
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, reg);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, reg);
 }
 
 static void faraday_pci_irq_handler(struct irq_desc *desc)
@@ -282,7 +298,7 @@ static void faraday_pci_irq_handler(struct irq_desc *desc)
 	struct irq_chip *irqchip = irq_desc_get_chip(desc);
 	unsigned int irq_stat, reg, i;
 
-	faraday_pci_read_config(p->bus, 0, FARADAY_PCI_CTRL2, 4, &reg);
+	faraday_raw_pci_read_config(p, 0, 0, FARADAY_PCI_CTRL2, 4, &reg);
 	irq_stat = reg >> PCI_CTRL2_INTSTS_SHIFT;
 
 	chained_irq_enter(irqchip, desc);
@@ -403,8 +419,8 @@ static int faraday_pci_parse_map_dma_ranges(struct faraday_pci *p,
 		dev_info(dev, "DMA MEM%d BASE: 0x%016llx -> 0x%016llx config %08x\n",
 			 i + 1, range.pci_addr, end, val);
 		if (i <= 2) {
-			faraday_pci_write_config(p->bus, 0, confreg[i],
-						 4, val);
+			faraday_raw_pci_write_config(p, 0, 0, confreg[i],
+						     4, val);
 		} else {
 			dev_err(dev, "ignore extraneous dma-range %d\n", i);
 			break;
@@ -496,17 +512,8 @@ static int faraday_pci_probe(struct platform_device *pdev)
 	val |= PCI_COMMAND_MEMORY;
 	val |= PCI_COMMAND_MASTER;
 	writel(val, p->base + PCI_CTRL);
-
-	list_splice_init(&res, &host->windows);
-	ret = pci_register_host_bridge(host);
-	if (ret) {
-		dev_err(dev, "failed to register host: %d\n", ret);
-		return ret;
-	}
-	p->bus = host->bus;
-
 	/* Mask and clear all interrupts */
-	faraday_pci_write_config(p->bus, 0, FARADAY_PCI_CTRL2 + 2, 2, 0xF000);
+	faraday_raw_pci_write_config(p, 0, 0, FARADAY_PCI_CTRL2 + 2, 2, 0xF000);
 	if (variant->cascaded_irq) {
 		ret = faraday_pci_setup_cascaded_irq(p);
 		if (ret) {
@@ -519,6 +526,14 @@ static int faraday_pci_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	list_splice_init(&res, &host->windows);
+	ret = pci_register_host_bridge(host);
+	if (ret) {
+		dev_err(dev, "failed to register host: %d\n", ret);
+		return ret;
+	}
+	p->bus = host->bus;
+
 	pci_scan_child_bus(p->bus);
 	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
 	pci_bus_assign_resources(p->bus);