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Subject[PATCH 2.6] scx200_acb: Use PCI I/O resource when appropriate
The CS5535 and CS5536 both define the I/O base for the SMBUS device in a 
PCI header. This patch uses that header for the I/O base rather then
using the MSR backdoor.

This patch isn't as urgent as the other one, so it can probably take the
usual trip up through Greg's tree.

--
Jordan Crouse
Senior Linux Engineer
AMD - Personal Connectivity Solutions Group
<www.amd.com/embeddedprocessors>
[PATCH] scx200_acb: Use PCI I/O resource when appropriate

From: Jordan Crouse <jordan.crouse@amd.com>

On the CS5535 and CS5536, the I/O resource is allocated through PCI,
so use that instead of using the MSR backdoor.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
---
drivers/i2c/busses/scx200_acb.c | 114 +++++++++++++++++++++++++++------------
1 files changed, 78 insertions(+), 36 deletions(-)
diff --git a/drivers/i2c/busses/scx200_acb.c b/drivers/i2c/busses/scx200_acb.c
index e7a2225..454492f 100644
--- a/drivers/i2c/busses/scx200_acb.c
+++ b/drivers/i2c/busses/scx200_acb.c
@@ -33,7 +33,6 @@
#include <linux/delay.h>
#include <linux/mutex.h>
#include <asm/io.h>
-#include <asm/msr.h>

#include <linux/scx200.h>

@@ -85,6 +84,10 @@ struct scx200_acb_iface {
u8 *ptr;
char needs_reset;
unsigned len;
+
+ /* PCI device info */
+ struct pci_dev *pdev;
+ int bar;
};

/* Register Definitions */
@@ -417,7 +420,8 @@ static int scx200_acb_probe(struct scx20
return 0;
}

-static int __init scx200_acb_create(const char *text, int base, int index)
+static int __init scx200_acb_create(char *text, unsigned int base, int index,
+ struct pci_dev *pdev, int bar)
{
struct scx200_acb_iface *iface;
struct i2c_adapter *adapter;
@@ -444,13 +448,31 @@ static int __init scx200_acb_create(con
snprintf(description, sizeof(description), "%s ACCESS.bus [%s]",
text, adapter->name);

- if (request_region(base, 8, description) == 0) {
- printk(KERN_ERR NAME ": can't allocate io 0x%x-0x%x\n",
- base, base + 8-1);
- rc = -EBUSY;
- goto errout_free;
+ if (pdev != NULL) {
+
+ iface->pdev = pdev;
+ iface->bar = bar;
+
+ pci_enable_device_bars(iface->pdev, 1 << iface->bar);
+
+ if (pci_request_region(iface->pdev, iface->bar, description)) {
+ printk(KERN_ERR NAME ": can't allocate PCI region %d\n",
+ iface->bar);
+ rc = -EBUSY;
+ goto errout_free;
+ }
+
+ iface->base = pci_resource_start(iface->pdev, iface->bar);
+ } else {
+ if (request_region(base, 8, description) == 0) {
+ printk(KERN_ERR NAME ": can't allocate io 0x%x-0x%x\n",
+ base, base + 8 - 1);
+ rc = -EBUSY;
+ goto errout_free;
+ }
+
+ iface->base = base;
}
- iface->base = base;

rc = scx200_acb_probe(iface);
if (rc) {
@@ -474,7 +496,11 @@ static int __init scx200_acb_create(con
return 0;

errout_release:
- release_region(iface->base, 8);
+ if (iface->pdev != NULL)
+ pci_release_region(iface->pdev, iface->bar);
+ else
+ release_region(iface->base, 8);
+
errout_free:
kfree(iface);
errout:
@@ -487,49 +513,60 @@ static struct pci_device_id scx200[] = {
{ },
};

-static struct pci_device_id divil_pci[] = {
- { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) },
- { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
- { } /* NULL entry */
+/* On the CS5535 and CS5536, the SMBUS I/0 base is a PCI resource, so
+ we should allocate that resource through the PCI
+ subsystem. rather then going through the MSR back door.
+*/
+
+static struct {
+ unsigned int vendor;
+ unsigned int device;
+ char *name;
+ int bar;
+} divil_pci[] = {
+ {
+ PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA, "CS5535", 0}, {
+ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA, "CS5536", 0}
};

-#define MSR_LBAR_SMB 0x5140000B
+#define DIVIL_LENGTH (sizeof(divil_pci) / sizeof(divil_pci[0]))

static int scx200_add_cs553x(void)
{
- u32 low, hi;
- u32 smb_base;
-
- /* Grab & reserve the SMB I/O range */
- rdmsr(MSR_LBAR_SMB, low, hi);
+ int dev;
+ struct pci_dev *pdev;

- /* Check the IO mask and whether SMB is enabled */
- if (hi != 0x0000F001) {
- printk(KERN_WARNING NAME ": SMBus not enabled\n");
- return -ENODEV;
+ for (dev = 0; dev < DIVIL_LENGTH; dev++) {
+ pdev =
+ pci_find_device(divil_pci[dev].vendor,
+ divil_pci[dev].device, NULL);
+ if (pdev != NULL)
+ break;
}

- /* SMBus IO size is 8 bytes */
- smb_base = low & 0x0000FFF8;
+ if (pdev == NULL)
+ return -ENODEV;

- return scx200_acb_create("CS5535", smb_base, 0);
+ return scx200_acb_create(divil_pci[dev].name, 0, 0, pdev,
+ divil_pci[dev].bar);
}

static int __init scx200_acb_init(void)
{
int i;
- int rc = -ENODEV;
+ int rc = -ENODEV;

pr_debug(NAME ": NatSemi SCx200 ACCESS.bus Driver\n");

- /* Verify that this really is a SCx200 processor */
- if (pci_dev_present(scx200)) {
- for (i = 0; i < MAX_DEVICES; ++i) {
- if (base[i] > 0)
- rc = scx200_acb_create("SCx200", base[i], i);
- }
- } else if (pci_dev_present(divil_pci))
- rc = scx200_add_cs553x();
+ /* If this is a CS5535 or CS5536, then probe the PCI header */
+
+ if (!pci_dev_present(scx200))
+ return scx200_add_cs553x();
+
+ for (i = 0; i < MAX_DEVICES; ++i) {
+ if (base[i] > 0)
+ rc = scx200_acb_create("SCx200", base[i], i, NULL, 0);
+ }

return rc;
}
@@ -544,7 +581,12 @@ static void __exit scx200_acb_cleanup(vo
up(&scx200_acb_list_mutex);

i2c_del_adapter(&iface->adapter);
- release_region(iface->base, 8);
+
+ if (iface->pdev != NULL)
+ pci_release_region(iface->pdev, iface->bar);
+ else
+ release_region(iface->base, 8);
+
kfree(iface);
down(&scx200_acb_list_mutex);
}
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