[PATCH 2/2] x86: iosf: Add debugfs support

From: David E. Box
Date: Wed Aug 27 2014 - 17:43:35 EST


Allows access to the iosf sideband through debugfs.

Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/iosf_mbi.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)

diff --git a/arch/x86/kernel/iosf_mbi.c b/arch/x86/kernel/iosf_mbi.c
index d30acdc..bf848ca 100644
--- a/arch/x86/kernel/iosf_mbi.c
+++ b/arch/x86/kernel/iosf_mbi.c
@@ -22,6 +22,8 @@
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
+#include <linux/debugfs.h>
+#include <linux/capability.h>

#include <asm/iosf_mbi.h>

@@ -187,6 +189,75 @@ bool iosf_mbi_available(void)
}
EXPORT_SYMBOL(iosf_mbi_available);

+/********************** debugfs begin ****************************/
+static u32 dbg_mdr;
+static u32 dbg_mcr;
+static u32 dbg_mcrx;
+
+static int mcr_get(void *data, u64 *val)
+{
+ *val = *(u32 *)data;
+ return 0;
+}
+
+static int mcr_set(void *data, u64 val)
+{
+ u8 command = ((u32)val & 0xFF000000) >> 24,
+ port = ((u32)val & 0x00FF0000) >> 16,
+ offset = ((u32)val & 0x0000FF00) >> 8;
+ int err;
+
+ *(u32 *)data = val;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EACCES;
+
+ if (command & 1u)
+ err = iosf_mbi_write(port,
+ command,
+ dbg_mcrx | offset,
+ dbg_mdr);
+ else
+ err = iosf_mbi_read(port,
+ command,
+ dbg_mcrx | offset,
+ &dbg_mdr);
+
+ return err;
+}
+DEFINE_SIMPLE_ATTRIBUTE(iosf_mcr_fops, mcr_get, mcr_set , "%llx\n");
+
+static struct dentry *iosf_dbg;
+static void iosf_sideband_debug_init(void)
+{
+ struct dentry *d;
+
+ iosf_dbg = debugfs_create_dir("iosf_sb", NULL);
+ if (IS_ERR_OR_NULL(iosf_dbg))
+ return;
+
+ /* mdr */
+ d = debugfs_create_x32("mdr", 0660, iosf_dbg, &dbg_mdr);
+ if (IS_ERR_OR_NULL(d))
+ goto cleanup;
+
+ /* mcrx */
+ debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
+ if (IS_ERR_OR_NULL(d))
+ goto cleanup;
+
+ /* mcr - initiates mailbox tranaction */
+ debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
+ if (IS_ERR_OR_NULL(d))
+ goto cleanup;
+
+ return;
+
+cleanup:
+ debugfs_remove_recursive(d);
+}
+/********************** debugfs end ****************************/
+
static int iosf_mbi_probe(struct pci_dev *pdev,
const struct pci_device_id *unused)
{
@@ -217,11 +288,14 @@ static struct pci_driver iosf_mbi_pci_driver = {

static int __init iosf_mbi_init(void)
{
+ iosf_sideband_debug_init();
return pci_register_driver(&iosf_mbi_pci_driver);
}

static void __exit iosf_mbi_exit(void)
{
+ debugfs_remove_recursive(iosf_dbg);
+
pci_unregister_driver(&iosf_mbi_pci_driver);
if (mbi_pdev) {
pci_dev_put(mbi_pdev);
--
1.9.1

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