[PATCH 03/10] IOCHK interface for I/O error handling/detecting

[Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>]

[This is 3 of 10 patches, "iochk-03-register.patch"]

- Implement ia64 version of basic codes:
     iochk_clear, iochk_read, iochk_init, and iocookie

   The direction is:

     - Have a "now in check" global list, "iochk_devices",
       for future use.

     - Take a lock, "iochk_lock", to protect the global list.

     - iochk_clear packs *dev into iocookie, and add it to
       the global list. After all prepared, clear error-flag
       in cookie to start io-critical-session.

     - iochk_read checks error-flag and device's status
       register. After removing iocookie from list, return
       the result.

This is too simple. We need more codes... See next (4 of 10).

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

---

  arch/ia64/lib/iomap_check.c |   54 ++++++++++++++++++++++++++++++++++++++++++--
  include/asm-ia64/io.h       |    8 +++++-
  2 files changed, 59 insertions(+), 3 deletions(-)

Index: linux-2.6.11.11/arch/ia64/lib/iomap_check.c
===================================================================
--- linux-2.6.11.11.orig/arch/ia64/lib/iomap_check.c
+++ linux-2.6.11.11/arch/ia64/lib/iomap_check.c
@@ -4,24 +4,74 @@
   */

  #include <linux/pci.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>

  void iochk_init(void);
  void iochk_clear(iocookie *cookie, struct pci_dev *dev);
  int  iochk_read(iocookie *cookie);

+struct list_head iochk_devices;
+DEFINE_SPINLOCK(iochk_lock);	/* all works are excluded on this lock */
+
+static int have_error(struct pci_dev *dev);
+
  void iochk_init(void)
  {
  	/* setup */
+	INIT_LIST_HEAD(&iochk_devices);
  }

  void iochk_clear(iocookie *cookie, struct pci_dev *dev)
  {
-	/* register device etc. */
+	unsigned long flag;
+
+	INIT_LIST_HEAD(&(cookie->list));
+
+	cookie->dev = dev;
+
+	spin_lock_irqsave(&iochk_lock, flag);
+	list_add(&cookie->list, &iochk_devices);
+	spin_unlock_irqrestore(&iochk_lock, flag);
+
+	cookie->error = 0;
  }

  int iochk_read(iocookie *cookie)
  {
-	/* check error etc. */
+	unsigned long flag;
+	int ret = 0;
+
+	spin_lock_irqsave(&iochk_lock, flag);
+	if( cookie->error || have_error(cookie->dev) )
+		ret = 1;
+	list_del(&cookie->list);
+	spin_unlock_irqrestore(&iochk_lock, flag);
+
+	return ret;
+}
+
+static int have_error(struct pci_dev *dev)
+{
+	u16 status;
+
+	/* check status */
+	switch (dev->hdr_type) {
+	case PCI_HEADER_TYPE_NORMAL: /* 0 */
+		pci_read_config_word(dev, PCI_STATUS, &status);
+		break;
+	case PCI_HEADER_TYPE_BRIDGE: /* 1 */
+		pci_read_config_word(dev, PCI_SEC_STATUS, &status);
+		break;
+	case PCI_HEADER_TYPE_CARDBUS: /* 2 */
+	default:
+		BUG();
+	}
+
+	if ( (status & PCI_STATUS_REC_TARGET_ABORT)
+		|| (status & PCI_STATUS_REC_MASTER_ABORT)
+		|| (status & PCI_STATUS_DETECTED_PARITY) )
+		return 1;

  	return 0;
  }
Index: linux-2.6.11.11/include/asm-ia64/io.h
===================================================================
--- linux-2.6.11.11.orig/include/asm-ia64/io.h
+++ linux-2.6.11.11/include/asm-ia64/io.h
@@ -72,9 +72,15 @@ extern unsigned int num_io_spaces;
  #include <asm/system.h>

  #ifdef CONFIG_IOMAP_CHECK
+#include <linux/list.h>

  /* definition of ia64 iocookie */
-typedef unsigned long iocookie;
+struct __iocookie {
+	struct list_head	list;
+	struct pci_dev		*dev;	/* targeting device */
+	unsigned long		error;	/* error flag */
+};
+typedef struct __iocookie iocookie;

  /* enable ia64 iochk - See arch/ia64/lib/iomap_check.c */
  #define HAVE_ARCH_IOMAP_CHECK