IPMI: Detect register spacing on PCI interfaces

The IPMI spec defines a way to detect register spacing for PCI interfaces,
so implement it.

Signed-off-by: Steven Hsieh <sshsieh@broadcom.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 34 insertions, 2 deletions

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 83f85cf7fb1b..32a6c7e256bd 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -2424,6 +2424,38 @@ static void ipmi_pci_cleanup(struct smi_info *info)
         pci_disable_device(pdev);
 }
 
+static int __devinit ipmi_pci_probe_regspacing(struct smi_info *info)
+{
+        if (info->si_type == SI_KCS) {
+                unsigned char   status;
+                int             regspacing;
+
+                info->io.regsize = DEFAULT_REGSIZE;
+                info->io.regshift = 0;
+                info->io_size = 2;
+                info->handlers = &kcs_smi_handlers;
+
+                /* detect 1, 4, 16byte spacing */
+                for (regspacing = DEFAULT_REGSPACING; regspacing <= 16;) {
+                        info->io.regspacing = regspacing;
+                        if (info->io_setup(info)) {
+                                dev_err(info->dev,
+                                        "Could not setup I/O space\n");
+                                return DEFAULT_REGSPACING;
+                        }
+                        /* write invalid cmd */
+                        info->io.outputb(&info->io, 1, 0x10);
+                        /* read status back */
+                        status = info->io.inputb(&info->io, 1);
+                        info->io_cleanup(info);
+                        if (status)
+                                return regspacing;
+                        regspacing *= 4;
+                }
+        }
+        return DEFAULT_REGSPACING;
+}
+
 static int __devinit ipmi_pci_probe(struct pci_dev *pdev,
                                     const struct pci_device_id *ent)
 {
@@ -2476,8 +2508,8 @@ static int __devinit ipmi_pci_probe(struct pci_dev *pdev,
         }
         info->io.addr_data = pci_resource_start(pdev, 0);
 
-        info->io.regspacing = DEFAULT_REGSPACING;
-        info->io.regsize = DEFAULT_REGSPACING;
+        info->io.regspacing = ipmi_pci_probe_regspacing(info);
+        info->io.regsize = DEFAULT_REGSIZE;
         info->io.regshift = 0;
 
         info->irq = pdev->irq;