sh: pci: Support asynchronous initialization of SH-X3 PCIe channels.

SH-X3 controllers all have pretty dire delays needed for PHY wakeup, so
we attempt to mitigate the damage by bringing them up asynchronously,
simply using the synchronization points for persistent bridge to channel
numbering.
Signed-off-by: NPaul Mundt <lethal@linux-sh.org>

arch/sh/drivers/pci/pcie-sh7786.c

 /*
  * Low-Level PCI Express Support for the SH7786
  *
- *  Copyright (C) 2009 - 2010  Paul Mundt
+ *  Copyright (C) 2009 - 2011  Paul Mundt
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  */
+#define pr_fmt(fmt) "PCI: " fmt
+
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/io.h>
+#include <linux/async.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/clk.h>
@@ -31,7 +34,7 @@ static unsigned int nr_ports;
 
 static struct sh7786_pcie_hwops {
 	int (*core_init)(void);
-	int (*port_init_hw)(struct sh7786_pcie_port *port);
+	async_func_ptr *port_init_hw;
 } *sh7786_pcie_hwops;
 
 static struct resource sh7786_pci0_resources[] = {
@@ -474,8 +477,9 @@ static int __init sh7786_pcie_core_init(void)
 	return test_mode_pin(MODE_PIN12) ? 3 : 2;
 }
 
-static int __init sh7786_pcie_init_hw(struct sh7786_pcie_port *port)
+static void __init sh7786_pcie_init_hw(void *data, async_cookie_t cookie)
 {
+	struct sh7786_pcie_port *port = data;
 	int ret;
 
 	/*
@@ -488,18 +492,30 @@ static int __init sh7786_pcie_init_hw(struct sh7786_pcie_port *port)
 	 * Setup clocks, needed both for PHY and PCIe registers.
 	 */
 	ret = pcie_clk_init(port);
-	if (unlikely(ret < 0))
-		return ret;
+	if (unlikely(ret < 0)) {
+		pr_err("clock initialization failed for port#%d\n",
+		       port->index);
+		return;
+	}
 
 	ret = phy_init(port);
-	if (unlikely(ret < 0))
-		return ret;
+	if (unlikely(ret < 0)) {
+		pr_err("phy initialization failed for port#%d\n",
+		       port->index);
+		return;
+	}
 
 	ret = pcie_init(port);
-	if (unlikely(ret < 0))
-		return ret;
+	if (unlikely(ret < 0)) {
+		pr_err("core initialization failed for port#%d\n",
+			       port->index);
+		return;
+	}
 
-	return register_pci_controller(port->hose);
+	/* In the interest of preserving device ordering, synchronize */
+	async_synchronize_cookie(cookie);
+
+	register_pci_controller(port->hose);
 }
 
 static struct sh7786_pcie_hwops sh7786_65nm_pcie_hwops __initdata = {
@@ -510,7 +526,7 @@ static struct sh7786_pcie_hwops sh7786_65nm_pcie_hwops __initdata = {
 static int __init sh7786_pcie_init(void)
 {
 	struct clk *platclk;
-	int ret = 0, i;
+	int i;
 
 	printk(KERN_NOTICE "PCI: Starting initialization.\n");
 
@@ -552,13 +568,7 @@ static int __init sh7786_pcie_init(void)
 		port->hose		= sh7786_pci_channels + i;
 		port->hose->io_map_base	= port->hose->resources[0].start;
 
-		ret |= sh7786_pcie_hwops->port_init_hw(port);
-	}
-
-	if (unlikely(ret)) {
-		clk_disable(platclk);
-		clk_put(platclk);
-		return ret;
+		async_schedule(sh7786_pcie_hwops->port_init_hw, port);
 	}
 
 	return 0;