[PATCH] I2O: fix and workaround for Motorola/Freescale controller

- This controller violates the I2O spec for the I/O registers.  The patch
  contains a workaround which moves the registers to the proper location.
  (originally author: Matthew Starzewski)

- If a message frame is beyond the mapped address range a error is
  returned.

Signed-off-by: Markus Lidel <Markus.Lidel@shadowconnect.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 25 insertions, 2 deletions

diff --git a/drivers/message/i2o/core.h b/drivers/message/i2o/core.h
index 90628562851e..184974cc734d 100644
--- a/drivers/message/i2o/core.h
+++ b/drivers/message/i2o/core.h
@@ -60,4 +60,7 @@ extern void i2o_iop_remove(struct i2o_controller *);
 #define I2O_IN_PORT     0x40
 #define I2O_OUT_PORT    0x44
 
+/* Motorola/Freescale specific register offset */
+#define I2O_MOTOROLA_PORT_OFFSET        0x10400
+
 #define I2O_IRQ_OUTBOUND_POST   0x00000008
diff --git a/drivers/message/i2o/pci.c b/drivers/message/i2o/pci.c
index e2e3fc79c78a..4f1515cae5dc 100644
--- a/drivers/message/i2o/pci.c
+++ b/drivers/message/i2o/pci.c
@@ -168,6 +168,24 @@ static int __devinit i2o_pci_alloc(struct i2o_controller *c)
         c->in_port = c->base.virt + I2O_IN_PORT;
         c->out_port = c->base.virt + I2O_OUT_PORT;
 
+        /* Motorola/Freescale chip does not follow spec */
+        if (pdev->vendor == PCI_VENDOR_ID_MOTOROLA && pdev->device == 0x18c0) {
+                /* Check if CPU is enabled */
+                if (be32_to_cpu(readl(c->base.virt + 0x10000)) & 0x10000000) {
+                        printk(KERN_INFO "%s: MPC82XX needs CPU running to "
+                               "service I2O.\n", c->name);
+                        i2o_pci_free(c);
+                        return -ENODEV;
+                } else {
+                        c->irq_status += I2O_MOTOROLA_PORT_OFFSET;
+                        c->irq_mask += I2O_MOTOROLA_PORT_OFFSET;
+                        c->in_port += I2O_MOTOROLA_PORT_OFFSET;
+                        c->out_port += I2O_MOTOROLA_PORT_OFFSET;
+                        printk(KERN_INFO "%s: MPC82XX workarounds activated.\n",
+                               c->name);
+                }
+        }
+
         if (i2o_dma_alloc(dev, &c->status, 8, GFP_KERNEL)) {
                 i2o_pci_free(c);
                 return -ENOMEM;
diff --git a/include/linux/i2o.h b/include/linux/i2o.h
index 9ba806796667..5a9d8c599171 100644
--- a/include/linux/i2o.h
+++ b/include/linux/i2o.h
@@ -1115,9 +1115,11 @@ static inline struct i2o_message *i2o_msg_get(struct i2o_controller *c)
                 return ERR_PTR(-ENOMEM);
 
         mmsg->mfa = readl(c->in_port);
-        if (mmsg->mfa == I2O_QUEUE_EMPTY) {
+        if (unlikely(mmsg->mfa >= c->in_queue.len)) {
                 mempool_free(mmsg, c->in_msg.mempool);
-                return ERR_PTR(-EBUSY);
+                if(mmsg->mfa == I2O_QUEUE_EMPTY)
+                        return ERR_PTR(-EBUSY);
+                return ERR_PTR(-EFAULT);
         }
 
         return &mmsg->msg;