Author: myles
Date: 2008-11-04 22:32:59 +0100 (Tue, 04 Nov 2008)
New Revision: 980

Modified:
   coreboot-v3/device/pci_device.c
Log:
This patch clarifies/adds comments and changes names in device/pci_device.c

It also changes %p debug statements in various places.  I think they get in
the way of diffs when you have log files to compare.  I don't want to see the
allocation differences most of the time.  I turned most of them into NULL
checks.  If they were supposed to be "Where are we in device allocation?"
checks, we could make them into that too.

It's a work-in-progress. Comments welcome.

I think most of the changes are self explanatory, but this one might not be:

If you are reading all the BARs from a device, and you come to a 64-bit BAR.
No matter why you skip it, you should skip it as a 64-bit BAR, and not try to
read the upper half as the next 32-bit BAR.

Because of that, set the 64-bit flag IORESOURCE_PCI64 early, and don't clear
it on return.

Signed-off-by: Myles Watson <[EMAIL PROTECTED]>
Acked-by: Ronald G. Minnich <[EMAIL PROTECTED]>


Modified: coreboot-v3/device/pci_device.c
===================================================================
--- coreboot-v3/device/pci_device.c     2008-11-04 17:00:07 UTC (rev 979)
+++ coreboot-v3/device/pci_device.c     2008-11-04 21:32:59 UTC (rev 980)
@@ -30,11 +30,13 @@
 #include <device/device.h>
 #include <device/pci.h>
 #include <device/pci_ids.h>
+/* We should move these so they're really config options */
 #define CONFIG_HYPERTRANSPORT_PLUGIN_SUPPORT 0
 #define CONFIG_PCIX_PLUGIN_SUPPORT 0
 #define CONFIG_PCIE_PLUGIN_SUPPORT 0
 #define CONFIG_CARDBUS_PLUGIN_SUPPORT 0
 #define CONFIG_AGP_PLUGIN_SUPPORT 0
+
 #if CONFIG_HYPERTRANSPORT_PLUGIN_SUPPORT == 1
 #include <device/hypertransport.h>
 #endif
@@ -100,8 +102,16 @@
        return ones ^ zeroes;
 }
 
-unsigned int pci_find_next_capability(struct device *dev, unsigned int cap,
-                                     unsigned int last)
+/**
+ * Given a device, a capability type, and a last position, return the next
+ * matching capability. Always start at the head of the list.
+ *
+ * @param dev Pointer to the device structure.
+ * @param cap_type PCI_CAP_LIST_ID of the PCI capability we're looking for.
+ * @param last_pos Location of the PCI capability register to start from.
+ */
+unsigned int pci_find_next_capability(struct device *dev, unsigned int 
cap_type,
+                                     unsigned int last_pos)
 {
        unsigned int pos;
        unsigned int status;
@@ -124,27 +134,35 @@
        }
        pos = pci_read_config8(dev, pos);
        while (reps-- && (pos >= 0x40)) { /* Loop through the linked list. */
-               int this_cap;
+               int this_cap_type;
                pos &= ~3;
-               this_cap = pci_read_config8(dev, pos + PCI_CAP_LIST_ID);
-               printk(BIOS_SPEW, "Capability: 0x%02x @ 0x%02x\n", cap, pos);
-               if (this_cap == 0xff) {
+               this_cap_type = pci_read_config8(dev, pos + PCI_CAP_LIST_ID);
+               printk(BIOS_SPEW, "Capability: 0x%02x @ 0x%02x\n",
+                       this_cap_type, pos);
+               if (this_cap_type == 0xff) {
                        break;
                }
-               if (!last && (this_cap == cap)) {
+               if (!last_pos && (this_cap_type == cap_type)) {
                        return pos;
                }
-               if (last == pos) {
-                       last = 0;
+               if (last_pos == pos) { /* Return the next match. */
+                       last_pos = 0;
                }
                pos = pci_read_config8(dev, pos + PCI_CAP_LIST_NEXT);
        }
        return 0;
 }
 
-unsigned int pci_find_capability(struct device *dev, unsigned int cap)
+/**
+ * Given a device, and a capability type, return the next matching
+ * capability. Always start at the head of the list.
+ *
+ * @param dev Pointer to the device structure.
+ * @param cap_type PCI_CAP_LIST_ID of the PCI capability we're looking for.
+ */
+unsigned int pci_find_capability(struct device *dev, unsigned int cap_type)
 {
-       return pci_find_next_capability(dev, cap, 0);
+       return pci_find_next_capability(dev, cap_type, 0);
 }
 
 /**
@@ -167,9 +185,9 @@
 
        /* save the base address */
        if (value & PCI_BASE_ADDRESS_SPACE_IO)
-               base &= ~PCI_BASE_ADDRESS_IO_ATTR_MASK;
+               base = value & ~PCI_BASE_ADDRESS_IO_ATTR_MASK;
        else
-               base &= ~PCI_BASE_ADDRESS_MEM_ATTR_MASK;
+               base = value & ~PCI_BASE_ADDRESS_MEM_ATTR_MASK;
 
        /* See which bits move. */
        moving = pci_moving_config32(dev, index);
@@ -184,6 +202,7 @@
                /* Find the high bits that move. */
                moving |=
                    ((resource_t) pci_moving_config32(dev, index + 4)) << 32;
+               resource->flags |= IORESOURCE_PCI64;
        }
 
        /* Find the resource constraints.
@@ -220,7 +239,11 @@
                               "%s register %02lx(%08lx), read-only ignoring 
it\n",
                               dev_path(dev), index, value);
                }
-               resource->flags = 0;
+               /* resource->flags = 0;
+                * Shouldn't zero because we'll get off with 64-bit BARs.
+                * Are there any others to save?
+                */
+               resource->flags &= ~IORESOURCE_PCI64;
        } else if (attr & PCI_BASE_ADDRESS_SPACE_IO) {
                /* An I/O mapped base address. */
                attr &= PCI_BASE_ADDRESS_IO_ATTR_MASK;
@@ -244,7 +267,6 @@
                } else if (attr == PCI_BASE_ADDRESS_MEM_LIMIT_64) {
                        /* 64bit limit. */
                        resource->limit = 0xffffffffffffffffULL;
-                       resource->flags |= IORESOURCE_PCI64;
                } else {
                        /* Invalid value. */
                        resource->flags = 0;
@@ -258,6 +280,12 @@
        return resource;
 }
 
+/**
+ * Given a device and an index, read the size of the BAR for that register. 
+ *
+ * @param dev Pointer to the device structure.
+ * @param index Address of the PCI configuration register.
+ */
 static void pci_get_rom_resource(struct device *dev, unsigned long index)
 {
        struct resource *resource;
@@ -265,8 +293,7 @@
        resource_t moving, limit;
 
        if ((dev->on_mainboard) && (dev->rom_address == 0)) {
-               // Skip it if rom_address is not set in MB Config.lb.
-               // TODO: No more Config.lb in coreboot-v3.
+               // Skip it if rom_address is not set in the mainboard's dts.
                return;
        }
 
@@ -278,6 +305,7 @@
 
        /* See which bits move. */
        moving = pci_moving_config32(dev, index);
+
        /* Clear the Enable bit. */
        moving = moving & ~PCI_ROM_ADDRESS_ENABLE;
 
@@ -298,23 +326,19 @@
                        resource->gran += 1;
                }
                resource->limit = limit = moving | (resource->size - 1);
-       }
-
-       if (moving == 0) {
+               resource->flags |= IORESOURCE_MEM | IORESOURCE_READONLY;
+       } else {
                if (value != 0) {
                        printk(BIOS_DEBUG,
                               "%s register %02lx(%08lx), read-only ignoring 
it\n",
                               dev_path(dev), index, value);
                }
                resource->flags = 0;
-       } else {
-               resource->flags |= IORESOURCE_MEM | IORESOURCE_READONLY;
        }
 
        /* For on board device with embedded ROM image, the ROM image is at
-        * fixed address specified in the Config.lb, the dev->rom_address is
+        * fixed address specified in the dts, the dev->rom_address is
         * inited by driver_pci_onboard_ops::enable_dev() */
-       /* TODO: No more Config.lb in coreboot-v3. */
        if ((dev->on_mainboard) && (dev->rom_address != 0)) {
                resource->base = dev->rom_address;
                resource->flags |= IORESOURCE_MEM | IORESOURCE_READONLY |
@@ -718,7 +742,7 @@
 
 void pci_dev_init(struct device *dev)
 {
-       printk(BIOS_SPEW, "PCI: pci_dev_init\n");
+       printk(BIOS_SPEW, "PCI: pci_dev_init %s\n", dev->dtsname);
 #ifdef CONFIG_PCI_OPTION_ROM_RUN
        void run_bios(struct device *dev, unsigned long addr);
        struct rom_header *rom, *ram;
@@ -774,7 +798,7 @@
  * When only a PCI-Express capability is found the type
  * is examined to see which type of bridge we have.
  *
- * @param dev TODO
+ * @param dev Pointer to the device structure of the bridge.
  * @return Appropriate bridge operations.
  */
 static struct device_operations *get_pci_bridge_ops(struct device *dev)
@@ -831,9 +855,10 @@
 }
 
 /**
- * Set up PCI device operation.
+ * Set up PCI device operation.  Check if it already has a driver.  If not, use
+ * find_device_operations, or set to a default based on type.
  *
- * @param dev TODO
+ * @param dev Pointer to the device whose pci_ops you want to set.
  * @see pci_drivers
  */
 static void set_pci_ops(struct device *dev)
@@ -842,8 +867,8 @@
        struct device_id id;
 
        if (dev->ops) {
-               printk(BIOS_SPEW, "%s: dev %p(%s) already has ops %p\n",
-                      __func__, dev, dev->dtsname, dev->ops);
+               printk(BIOS_SPEW, "%s: dev %s already has ops of type %x\n",
+                      __func__, dev->dtsname, dev->ops->id.type);
                return;
        }
 
@@ -888,8 +913,8 @@
                               dev->hdr_type);
                }
        }
-       printk(BIOS_INFO, "%s: dev %p(%s) set ops to %p\n", __func__, dev,
-              dev->dtsname, dev->ops);
+       printk(BIOS_INFO, "%s: dev %s set ops to type %x\n", __func__,
+              dev->dtsname, dev->ops->id.type);
        return;
 }
 
@@ -905,12 +930,12 @@
  * @return Pointer to the device structure found or NULL of we have not
  *        allocated a device for this devfn yet.
  */
-static struct device *pci_scan_get_dev(struct device **list, unsigned int 
devfn)
+static struct device *pci_get_dev(struct device **list, unsigned int devfn)
 {
        struct device *dev;
        dev = 0;
-       printk(BIOS_SPEW, "%s: list is %p, *list is %p\n", __func__, list,
-              *list);
+       printk(BIOS_SPEW, "%s: list is %sNULL, *list is %sNULL\n", __func__,
+               list?"NOT ":"", *list?"NOT ":"");
        for (; *list; list = &(*list)->sibling) {
                printk(BIOS_SPEW, "%s: check dev %s \n", __func__,
                       (*list)->dtsname);
@@ -927,7 +952,7 @@
                        /* Unlink from the list. */
                        dev = *list;
                        *list = (*list)->sibling;
-                       dev->sibling = 0;
+                       dev->sibling = NULL;
                        break;
                }
        }
@@ -962,8 +987,8 @@
  *
  * @param dev Pointer to the device structure if it already is in the device
  *         tree, i.e. was specified in the dts. It may not exist on hardware,
- *         however. Looking for hardware not yet in the device tree has this
- *         parameter as NULL.
+ *         however. When looking for hardware not yet in the device tree, this
+ *         parameter is NULL.
  * @param bus Pointer to the bus structure.
  * @param devfn A device/function number.
  * @return The device structure for the device if it exists in hardware
@@ -1021,7 +1046,6 @@
                 * this also handles optional devices that may not always
                 * show up.
                 */
-               /* If the chain is fully enumerated quit. */
                if ((id == 0xffffffff) || (id == 0x00000000) ||
                    (id == 0x0000ffff) || (id == 0xffff0000)) {
                        if (dev->enabled) {
@@ -1034,6 +1058,7 @@
                }
        }
        /* Read the rest of the PCI configuration information. */
+       /* Store the interesting information in the device structure. */
        hdr_type = pci_read_config8(dev, PCI_HEADER_TYPE);
        class = pci_read_config32(dev, PCI_CLASS_REVISION);
        dev->status = pci_read_config16(dev, PCI_STATUS);
@@ -1043,15 +1068,22 @@
        dev->irq_pin = pci_read_config8(dev, PCI_INTERRUPT_PIN);
        dev->min_gnt = pci_read_config8(dev, PCI_MIN_GNT);
        dev->max_lat = pci_read_config8(dev, PCI_MAX_LAT);
-#warning Per-device subsystem ID should only be read from the device if none 
has been specified for the device in the dts.
-       dev->subsystem_vendor = pci_read_config16(dev, PCI_SUBSYSTEM_VENDOR_ID);
-       dev->subsystem_device = pci_read_config16(dev, PCI_SUBSYSTEM_ID);
 
-       /* Store the interesting information in the device structure. */
+       /*Per-device subsystem ID should only be read from the device if none
+        * has been specified for the device in the dts.
+        */
+       if (!dev->subsystem_vendor && !dev->subsystem_device) {
+               dev->subsystem_vendor = 
+                               pci_read_config16(dev, PCI_SUBSYSTEM_VENDOR_ID);
+               dev->subsystem_device = 
+                               pci_read_config16(dev, PCI_SUBSYSTEM_ID);
+       }
+
        dev->id.type = DEVICE_ID_PCI;
        dev->id.pci.vendor = id & 0xffff;
        dev->id.pci.device = (id >> 16) & 0xffff;
        dev->hdr_type = hdr_type;
+
        /* Class code, the upper 3 bytes of PCI_CLASS_REVISION. */
        dev->class = class >> 8;
 
@@ -1070,9 +1102,7 @@
                dev->ops->phase3_enable(dev);
        }
 
-       /* Display the device and error if we don't have some PCI operations
-        * for it.
-        */
+       /* Display the device. */
        printk(BIOS_DEBUG, "%s [%s] %s%s\n",
               dev_path(dev), dev_id_string(&dev->id),
               dev->enabled ? "enabled" : "disabled",
@@ -1093,18 +1123,20 @@
  * @param bus Pointer to the bus structure.
  * @param min_devfn Minimum devfn to look at in the scan usually 0x00.
  * @param max_devfn Maximum devfn to look at in the scan usually 0xff.
- * @param max Current bus number.
- * @return The maximum bus number found, after scanning all subordinate buses.
+ * @param curr_bus Current bus number to be assigned.
+ * @return The new curr_bus, after scanning all subordinate buses.
  */
 unsigned int pci_scan_bus(struct bus *bus, unsigned int min_devfn,
-                         unsigned int max_devfn, unsigned int max)
+                         unsigned int max_devfn, unsigned int curr_bus)
 {
        unsigned int devfn;
        struct device *old_devices;
        struct device *child;
 
-       printk(BIOS_DEBUG, "%s start bus %p, bus->dev %p\n", __func__, bus,
-              bus->dev);
+       printk(BIOS_DEBUG, "%s start bus->dev %s bus %x\n", __func__,
+              bus->dev->dtsname, bus->link);
+
+#warning This check needs checking.
        if (bus->dev->path.type != DEVICE_PATH_PCI_BUS)
                printk(BIOS_ERR, "ERROR: pci_scan_bus called with incorrect "
                       "bus->dev->path.type, path is %s\n", dev_path(bus->dev));
@@ -1116,10 +1148,11 @@
        printk(BIOS_DEBUG, "PCI: pci_scan_bus for bus %02x\n", bus->secondary);
 #endif
 
+       /* Remove children of the bus, so the enumeration starts empty. */
        old_devices = bus->children;
-       printk(BIOS_DEBUG, "%s: old_devices %p, dev for this bus %p (%s)\n",
-              __func__, old_devices, bus->dev, bus->dev->dtsname);
-       bus->children = 0;
+       printk(BIOS_DEBUG, "%s: old_devices %s, dev for this bus %s\n",
+              __func__, old_devices?old_devices->dtsname:"NULL", 
bus->dev->dtsname);
+       bus->children = NULL;
 
        post_code(POST_STAGE2_PCISCANBUS_ENTER);
        printk(BIOS_SPEW, "PCI: scan devfn 0x%x to 0x%x\n", min_devfn,
@@ -1131,17 +1164,18 @@
                struct device *dev;
                printk(BIOS_SPEW, "PCI: devfn 0x%x\n", devfn);
 
-               /* First thing setup the device structure. */
-               dev = pci_scan_get_dev(&old_devices, devfn);
+               /* First thing look in the device tree. */
+               dev = pci_get_dev(&old_devices, devfn);
 
                printk(BIOS_SPEW,
-                      "PCI: pci_scan_bus pci_scan_get_dev returns dev %s\n",
+                      "PCI: pci_scan_bus pci_get_dev returns dev %s\n",
                       dev ? dev->dtsname : "None (no dev in tree yet)");
+
                /* See if a device is present and setup the device structure. */
                dev = pci_probe_dev(dev, bus, devfn);
                printk(BIOS_SPEW,
-                      "PCI: pci_scan_bus pci_probe_dev returns dev %p(%s)\n",
-                      dev, dev ? dev->dtsname : "None (not found)");
+                      "PCI: pci_scan_bus pci_probe_dev returns dev %s\n",
+                      dev ? dev->dtsname : "None (no response)");
 
                /* If this is not a multi function device, or the device is
                 * not present don't waste time probing another function. 
@@ -1158,9 +1192,8 @@
        printk(BIOS_SPEW, "PCI: Done for loop\n");
        post_code(POST_STAGE2_PCISCANBUS_DONEFORLOOP);
 
-       /* Die if any leftover static devices are are found.  
-        * There's probably a problem in the Config.lb.
-        * TODO: No more Config.lb in coreboot-v3.
+       /* Warn if any leftover static devices are are found.  
+        * There's probably a problem in the device tree (dts).
         */
        if (old_devices) {
                struct device *left;
@@ -1175,16 +1208,17 @@
         * scan the bus behind that child.
         */
        for (child = bus->children; child; child = child->sibling) {
-               max = dev_phase3_scan(child, max);
+               curr_bus = dev_phase3_scan(child, curr_bus);
        }
 
        /* We've scanned the bus and so we know all about what's on the other
         * side of any bridges that may be on this bus plus any devices.
         * Return how far we've got finding sub-buses.
         */
-       printk(BIOS_DEBUG, "PCI: pci_scan_bus returning with max=%03x\n", max);
+       printk(BIOS_DEBUG, "PCI: pci_scan_bus returning with curr_bus=%03x\n",
+               curr_bus);
        post_code(POST_STAGE2_PCISCANBUS_EXIT);
-       return max;
+       return curr_bus;
 }
 
 /**
@@ -1194,14 +1228,14 @@
  * This function works for almost all chipsets (AMD K8 is the exception).
  *
  * @param dev The PCI domain device.
- * @param max Maximum number of devices to scan.
- * @return TODO
+ * @param max The current bus number to be assigned.
+ * @return The current bus number returned by pci_scan_bus.
  */
-unsigned int pci_domain_scan_bus(struct device *dev, unsigned int max)
+unsigned int pci_domain_scan_bus(struct device *dev, unsigned int curr_bus)
 {
        printk(BIOS_SPEW, "pci_domain_scan_bus: calling pci_scan_bus\n");
        /* There is only one link on this device, and it is always link 0. */
-       return pci_scan_bus(&dev->link[0], PCI_DEVFN(0, 0), 0xff, max);
+       return pci_scan_bus(&dev->link[0], PCI_DEVFN(0, 0), 0xff, curr_bus);
 }
 
 /**


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