PATCH: pci_auto bridge support

["Bradley D. LaRonde" <brad@ltc.com>]

2001-10-26  Bradley D. LaRonde <brad@ltc.com>

* PCI bridge support.  See change log entry below.

--- arch/mips/kernel/pci_auto.c	2001/08/18 06:21:53	1.1
+++ arch/mips/kernel/pci_auto.c	2001/10/27 01:01:21
@@ -4,6 +4,7 @@
  * Author: Matt Porter <mporter@mvista.com>
  *
  * Copyright 2000, 2001 MontaVista Software Inc.
+ * Copyright 2001 Bradley D. LaRonde <brad@ltc.com>
  *
  * This program is free software; you can redistribute  it and/or modify it
  * under  the terms of  the GNU General  Public License as published by the
@@ -19,6 +20,15 @@
  * . change most int to u32.
  *
  * Further modified to include it as mips generic code, ppopov@mvista.com.
+ *
+ * 2001-10-26  Bradley D. LaRonde <brad@ltc.com>
+ * - Add a top_bus argument to the "early config" functions so that
+ *   they can set a fake parent bus pointer to convince the underlying
+ *   pci ops to use type 1 configuration for sub busses.
+ * - Set bridge base and limit registers correctly.
+ * - Align io and memory base properly before and after bridge setup.
+ * - Don't fall through to pci_setup_bars for bridge.
+ * - Reformat the debug output to look more like lspci's output.
  */
 
 #include <linux/kernel.h>
@@ -34,14 +44,47 @@
 #else
 #define	DBG(x...)	
 #endif
+
+/*
+ * These functions are used early on before PCI scanning is done
+ * and all of the pci_dev and pci_bus structures have been created.
+ */
+static struct pci_dev *fake_pci_dev(struct pci_channel *hose,
+	int top_bus, int busnr, int devfn)
+{
+	static struct pci_dev dev;
+	static struct pci_bus bus;
+
+	dev.bus = &bus;
+	dev.sysdata = hose;
+	dev.devfn = devfn;
+	bus.number = busnr;
+	bus.ops = hose->pci_ops;
+
+	if(busnr != top_bus)
+		/* Fake a parent bus structure. */
+		bus.parent = &bus;
+	else
+		bus.parent = NULL;
+
+	return &dev;
+}
+
+#define EARLY_PCI_OP(rw, size, type)					\
+int early_##rw##_config_##size(struct pci_channel *hose,		\
+	int top_bus, int bus, int devfn, int offset, type value)	\
+{									\
+	return pci_##rw##_config_##size(				\
+		fake_pci_dev(hose, top_bus, bus, devfn),		\
+		offset, value);						\
+}
 
-/* These are used for config access before all the PCI probing has been done. */
-int early_read_config_byte(struct pci_channel *hose, int bus, int dev_fn, int where, u8 *val);
-int early_read_config_word(struct pci_channel *hose, int bus, int dev_fn, int where, u16 *val);
-int early_read_config_dword(struct pci_channel *hose, int bus, int dev_fn, int where, u32 *val);
-int early_write_config_byte(struct pci_channel *hose, int bus, int dev_fn, int where, u8 val);
-int early_write_config_word(struct pci_channel *hose, int bus, int dev_fn, int where, u16 val);
-int early_write_config_dword(struct pci_channel *hose, int bus, int dev_fn, int where, u32 val);
+EARLY_PCI_OP(read, byte, u8 *)
+EARLY_PCI_OP(read, word, u16 *)
+EARLY_PCI_OP(read, dword, u32 *)
+EARLY_PCI_OP(write, byte, u8)
+EARLY_PCI_OP(write, word, u16)
+EARLY_PCI_OP(write, dword, u32)
 
 static u32 pciauto_lower_iospc;
 static u32 pciauto_upper_iospc;
@@ -51,6 +94,7 @@
 
 void __init 
 pciauto_setup_bars(struct pci_channel *hose,
+		   int top_bus,
 		   int current_bus,
 		   int pci_devfn)
 {
@@ -60,17 +104,14 @@
 	u32 * lower_limit;
 	int found_mem64 = 0;
 
-	DBG("PCI Autoconfig: Found Bus %d, Device %d, Function %d\n",
-	    current_bus, PCI_SLOT(pci_devfn), PCI_FUNC(pci_devfn) );
-
 	for (bar = PCI_BASE_ADDRESS_0; bar <= PCI_BASE_ADDRESS_5; bar+=4) {
 		/* Tickle the BAR and get the response */
-		early_write_config_dword(hose,
+		early_write_config_dword(hose, top_bus,
 					 current_bus,
 					 pci_devfn,
 					 bar,
 					 0xffffffff);
-		early_read_config_dword(hose,
+		early_read_config_dword(hose, top_bus,
 					current_bus,
 					pci_devfn,
 					bar,
@@ -80,12 +121,20 @@
 		if (!bar_response)
 			continue;
 
+		/*
+		 * Workaround for a BAR that doesn't use its upper word,
+		 * like the ALi 1535D+ PCI DC-97 Controller Modem (M5457).
+		 * bdl <brad@ltc.com>
+		 */
+		if (!(bar_response & 0xffff0000))
+			bar_response |= 0xffff0000;
+
 		/* Check the BAR type and set our address mask */
 		if (bar_response & PCI_BASE_ADDRESS_SPACE) {
 			addr_mask = PCI_BASE_ADDRESS_IO_MASK;
 			upper_limit = &pciauto_upper_iospc;
 			lower_limit = &pciauto_lower_iospc;
-			DBG("PCI Autoconfig: BAR %d, I/O, ", bar_nr);
+			DBG("        I/O");
 		} else {
 			if ((bar_response & PCI_BASE_ADDRESS_MEM_TYPE_MASK) ==
 			    PCI_BASE_ADDRESS_MEM_TYPE_64)
@@ -94,7 +143,7 @@
 			addr_mask = PCI_BASE_ADDRESS_MEM_MASK;		
 			upper_limit = &pciauto_upper_memspc;
 			lower_limit = &pciauto_lower_memspc;
-			DBG("PCI Autoconfig: BAR %d, Mem, ", bar_nr);
+			DBG("        Mem");
 		}
 
 		/* Calculate requested size */
@@ -104,7 +153,7 @@
 		bar_value = ((*lower_limit - 1) & ~(bar_size - 1)) + bar_size;
 
 		/* Write it out and update our limit */
-		early_write_config_dword(hose, current_bus, pci_devfn,
+		early_write_config_dword(hose, top_bus, current_bus, pci_devfn,
 					 bar, bar_value);
 
 		*lower_limit = bar_value + bar_size;
@@ -116,97 +165,99 @@
 		 */ 
 		if (found_mem64) {
 			bar += 4;
-			early_write_config_dword(hose,
+			early_write_config_dword(hose, top_bus,
 						 current_bus,
 						 pci_devfn,
 						 bar,
 						 0x00000000);
 		}
 
-		bar_nr++;
+		DBG(" at 0x%.8x [size=0x%x]\n", bar_value, bar_size);
 
-		DBG("size=0x%x, address=0x%x\n",
-		    bar_size, bar_value);
+		bar_nr++;
 	}
 
 }
 
 void __init
 pciauto_prescan_setup_bridge(struct pci_channel *hose,
+			     int top_bus,
 			     int current_bus,
 			     int pci_devfn,
 			     int sub_bus)
 {
-	int cmdstat;
-
 	/* Configure bus number registers */
-	early_write_config_byte(hose, current_bus, pci_devfn,
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
 	                        PCI_PRIMARY_BUS, current_bus);
-	early_write_config_byte(hose, current_bus, pci_devfn,
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
 				PCI_SECONDARY_BUS, sub_bus + 1);
-	early_write_config_byte(hose, current_bus, pci_devfn,
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
 				PCI_SUBORDINATE_BUS, 0xff);
-
-	/* Round memory allocator to 1MB boundary */
-	pciauto_upper_memspc &= ~(0x100000 - 1);
 
-	/* Round I/O allocator to 4KB boundary */
-	pciauto_upper_iospc &= ~(0x1000 - 1);
+	/* Align memory and I/O to 1MB and 4KB boundaries. */
+	pciauto_lower_memspc = (pciauto_lower_memspc + (0x100000 - 1))
+		& ~(0x100000 - 1);
+	pciauto_lower_iospc = (pciauto_lower_iospc + (0x1000 - 1))
+		& ~(0x1000 - 1);
+
+	/* Set base (lower limit) of address range behind bridge. */
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+		PCI_MEMORY_BASE, pciauto_lower_memspc >> 16);
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
+		PCI_IO_BASE, (pciauto_lower_iospc & 0x0000f000) >> 8);
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+		PCI_IO_BASE_UPPER16, pciauto_lower_iospc >> 16);
 
-	/* Set up memory and I/O filter limits, assume 32-bit I/O space */
-	early_write_config_word(hose, current_bus, pci_devfn, PCI_MEMORY_LIMIT,
-				((pciauto_upper_memspc - 1) & 0xfff00000) >> 16);
-	early_write_config_byte(hose, current_bus, pci_devfn, PCI_IO_LIMIT,
-				((pciauto_upper_iospc - 1) & 0x0000f000) >> 8);
-	early_write_config_word(hose, current_bus, pci_devfn,
-				PCI_IO_LIMIT_UPPER16,
-				((pciauto_upper_iospc - 1) & 0xffff0000) >> 16);
-			
 	/* We don't support prefetchable memory for now, so disable */
-	early_write_config_word(hose, current_bus, pci_devfn,
-				PCI_PREF_MEMORY_BASE, 0x1000);
-	early_write_config_word(hose, current_bus, pci_devfn,
-				PCI_PREF_MEMORY_LIMIT, 0x1000);
-
-	/* Enable memory and I/O accesses, enable bus master */
-	early_read_config_dword(hose, current_bus, pci_devfn, PCI_COMMAND,
-				&cmdstat);
-	early_write_config_dword(hose, current_bus, pci_devfn, PCI_COMMAND,
-				 cmdstat | PCI_COMMAND_IO | PCI_COMMAND_MEMORY |
-				 PCI_COMMAND_MASTER);
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+				PCI_PREF_MEMORY_BASE, 0);
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+				PCI_PREF_MEMORY_LIMIT, 0);
 }
 
 void __init
 pciauto_postscan_setup_bridge(struct pci_channel *hose,
+			      int top_bus,
 			      int current_bus,
 			      int pci_devfn,
 			      int sub_bus)
 {
+	u32 temp;
+
 	/* Configure bus number registers */
-	early_write_config_byte(hose, current_bus, pci_devfn,
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
 				PCI_SUBORDINATE_BUS, sub_bus);
 
-	/* Round memory allocator to 1MB boundary */
-	pciauto_upper_memspc &= ~(0x100000 - 1);
-	early_write_config_word(hose, current_bus, pci_devfn, PCI_MEMORY_BASE,
-				pciauto_upper_memspc >> 16);
-
-	/* Round I/O allocator to 4KB boundary */
-	pciauto_upper_iospc &= ~(0x1000 - 1);
-	early_write_config_byte(hose, current_bus, pci_devfn, PCI_IO_BASE,
-				(pciauto_upper_iospc & 0x0000f000) >> 8);
-	early_write_config_word(hose, current_bus, pci_devfn,
-				PCI_IO_BASE_UPPER16, pciauto_upper_iospc >> 16);
+	/* Set upper limit of address range behind bridge. */
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+		PCI_MEMORY_LIMIT, pciauto_lower_memspc >> 16);
+	early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
+		PCI_IO_LIMIT, (pciauto_lower_iospc & 0x0000f000) >> 8);
+	early_write_config_word(hose, top_bus, current_bus, pci_devfn,
+		PCI_IO_LIMIT_UPPER16, pciauto_lower_iospc >> 16);
+
+	/* Align memory and I/O to 1MB and 4KB boundaries. */
+	pciauto_lower_memspc = (pciauto_lower_memspc + (0x100000 - 1))
+		& ~(0x100000 - 1);
+	pciauto_lower_iospc = (pciauto_lower_iospc + (0x1000 - 1))
+		& ~(0x1000 - 1);
+
+	/* Enable memory and I/O accesses, enable bus master */
+	early_read_config_dword(hose, top_bus, current_bus, pci_devfn,
+		PCI_COMMAND, &temp);
+	early_write_config_dword(hose, top_bus, current_bus, pci_devfn,
+		PCI_COMMAND, temp | PCI_COMMAND_IO | PCI_COMMAND_MEMORY
+		| PCI_COMMAND_MASTER);
 }
 
 #define      PCIAUTO_IDE_MODE_MASK           0x05
 
 int __init
-pciauto_bus_scan(struct pci_channel *hose, int current_bus)
+pciauto_bus_scan(struct pci_channel *hose, int top_bus, int current_bus)
 {
 	int sub_bus;
 	u32 pci_devfn, pci_class, cmdstat, found_multi=0;
-	unsigned short vid;
+	unsigned short vid, did;
 	unsigned char header_type;
 	int devfn_start = 0;
 	int devfn_stop = 0xff;
@@ -223,54 +274,70 @@
 		if (PCI_FUNC(pci_devfn) && !found_multi)
 			continue;
 
-		early_read_config_byte(hose, current_bus, pci_devfn,
+		early_read_config_word(hose, top_bus, current_bus, pci_devfn,
+				       PCI_VENDOR_ID, &vid);
+
+		if (vid == 0xffff) continue;
+
+		early_read_config_byte(hose, top_bus, current_bus, pci_devfn,
 				       PCI_HEADER_TYPE, &header_type);
 
 		if (!PCI_FUNC(pci_devfn))
 			found_multi = header_type & 0x80;
 
-		early_read_config_word(hose, current_bus, pci_devfn,
-				       PCI_VENDOR_ID, &vid);
+		early_read_config_word(hose, top_bus, current_bus, pci_devfn,
+				       PCI_DEVICE_ID, &did);
 
-		if (vid == 0xffff) continue;
-
-		early_read_config_dword(hose, current_bus, pci_devfn,
+		early_read_config_dword(hose, top_bus, current_bus, pci_devfn,
 					PCI_CLASS_REVISION, &pci_class);
+
+		DBG("%.2x:%.2x.%x Class %.4x: %.4x:%.4x",
+			current_bus, PCI_SLOT(pci_devfn), PCI_FUNC(pci_devfn),
+			pci_class >> 16, vid, did);
+		if (pci_class & 0xff)
+			DBG(" (rev %.2x)", pci_class & 0xff);
+		DBG("\n");
+
 		if ((pci_class >> 16) == PCI_CLASS_BRIDGE_PCI) {
-			DBG("PCI Autoconfig: Found P2P bridge, device %d\n", PCI_SLOT(pci_devfn));
-			pciauto_prescan_setup_bridge(hose, current_bus,
+			DBG("        Bridge: primary=%.2x, secondary=%.2x\n",
+				current_bus, sub_bus + 1);
+			pciauto_prescan_setup_bridge(hose, top_bus, current_bus,
 						     pci_devfn, sub_bus);
-			sub_bus = pciauto_bus_scan(hose, sub_bus+1);
-			pciauto_postscan_setup_bridge(hose, current_bus,
+			DBG("Scanning sub bus %.2x, I/O 0x%.8x, Mem 0x%.8x\n",
+				sub_bus + 1,
+				pciauto_lower_iospc, pciauto_lower_memspc);
+			sub_bus = pciauto_bus_scan(hose, top_bus, sub_bus+1);
+			DBG("Back to bus %.2x\n", current_bus);
+			pciauto_postscan_setup_bridge(hose, top_bus, current_bus,
 						      pci_devfn, sub_bus);
-
+			continue;
 		} else if ((pci_class >> 16) == PCI_CLASS_STORAGE_IDE) {
 
 			unsigned char prg_iface;
 
-			early_read_config_byte(hose, current_bus, pci_devfn,
-					       PCI_CLASS_PROG, &prg_iface);
+			early_read_config_byte(hose, top_bus, current_bus,
+				pci_devfn, PCI_CLASS_PROG, &prg_iface);
 			if (!(prg_iface & PCIAUTO_IDE_MODE_MASK)) {
-				DBG("PCI Autoconfig: Skipping legacy mode IDE controller\n");
+				DBG("Skipping legacy mode IDE controller\n");
 				continue;
 			}
 		}
 
-		/*
+ 		/*
 		 * Found a peripheral, enable some standard
 		 * settings
 		 */
-		early_read_config_dword(hose, current_bus, pci_devfn,
+		early_read_config_dword(hose, top_bus, current_bus, pci_devfn,
 					PCI_COMMAND, &cmdstat);
-		early_write_config_dword(hose, current_bus, pci_devfn,
+		early_write_config_dword(hose, top_bus, current_bus, pci_devfn,
 					 PCI_COMMAND, cmdstat | PCI_COMMAND_IO |
 					 PCI_COMMAND_MEMORY |
 					 PCI_COMMAND_MASTER);
-		early_write_config_byte(hose, current_bus, pci_devfn,
+		early_write_config_byte(hose, top_bus, current_bus, pci_devfn,
 					PCI_LATENCY_TIMER, 0x80);
 
 		/* Allocate PCI I/O and/or memory space */
-		pciauto_setup_bars(hose, current_bus, pci_devfn);
+		pciauto_setup_bars(hose, top_bus, current_bus, pci_devfn);
 	}
 	return sub_bus;
 }
@@ -283,41 +350,9 @@
 	pciauto_upper_iospc = hose->io_resource->end + 1;
 	pciauto_lower_memspc = hose->mem_resource->start;
 	pciauto_upper_memspc = hose->mem_resource->end + 1;
+	DBG("Autoconfig PCI channel 0x%p\n", hose);
+	DBG("Scanning bus %.2x, I/O 0x%.8x, Mem 0x%.8x\n",
+		busno, pciauto_lower_iospc, pciauto_lower_memspc);
 
-	return pciauto_bus_scan(hose, busno);
+	return pciauto_bus_scan(hose, busno, busno);
 }
-
-
-/*
- * These functions are used early on before PCI scanning is done
- * and all of the pci_dev and pci_bus structures have been created.
- */
-static struct pci_dev *fake_pci_dev(struct pci_channel *hose, int busnr,
-                                    int devfn)
-{
-	static struct pci_dev dev;
-	static struct pci_bus bus;
-
-	dev.bus = &bus;
-	dev.sysdata = hose;
-	dev.devfn = devfn;
-	bus.number = busnr;
-	bus.ops = hose->pci_ops;
-
-	return &dev;
-}
-
-#define EARLY_PCI_OP(rw, size, type)					\
-int early_##rw##_config_##size(struct pci_channel *hose, int bus,	\
-                               int devfn, int offset, type value)	\
-{									\
-	return pci_##rw##_config_##size(fake_pci_dev(hose, bus, devfn),	\
-	                                offset, value);			\
-}
-
-EARLY_PCI_OP(read, byte, u8 *)
-EARLY_PCI_OP(read, word, u16 *)
-EARLY_PCI_OP(read, dword, u32 *)
-EARLY_PCI_OP(write, byte, u8)
-EARLY_PCI_OP(write, word, u16)
-EARLY_PCI_OP(write, dword, u32)