[CASSINI]: Program parent Intel31154 bridge when necessary.
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
drivers/net/cassini.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 86 insertions(+), 0 deletions(-)
diff --git a/drivers/net/cassini.c b/drivers/net/cassini.c
index ff957f2..2336223 100644
--- a/drivers/net/cassini.c
+++ b/drivers/net/cassini.c
@@ -4846,6 +4846,90 @@ static int cas_ioctl(struct net_device *dev, struct
ifreq *ifr, int cmd)
return rc;
}
+/* When this chip sits underneath an Intel 31154 bridge, it is the
+ * only subordinate device and we can tweak the bridge settings to
+ * reflect that fact.
+ */
+static void __devinit cas_program_bridge(struct pci_dev *cas_pdev)
+{
+ struct pci_dev *pdev = cas_pdev->bus->self;
+ u32 val;
+
+ if (!pdev)
+ return;
+
+ if (pdev->vendor != 0x8086 || pdev->device != 0x537c)
+ return;
+
+ /* Clear bit 10 (Bus Parking Control) in the Secondary
+ * Arbiter Control/Status Register which lives at offset
+ * 0x41. Using a 32-bit word read/modify/write at 0x40
+ * is much simpler so that's how we do this.
+ */
+ pci_read_config_dword(pdev, 0x40, &val);
+ val &= ~0x00040000;
+ pci_write_config_dword(pdev, 0x40, val);
+
+ /* Max out the Multi-Transaction Timer settings since
+ * Cassini is the only device present.
+ *
+ * The register is 16-bit and lives at 0x50. When the
+ * settings are enabled, it extends the GRANT# signal
+ * for a requestor after a transaction is complete. This
+ * allows the next request to run without first needing
+ * to negotiate the GRANT# signal back.
+ *
+ * Bits 12:10 define the grant duration:
+ *
+ * 1 -- 16 clocks
+ * 2 -- 32 clocks
+ * 3 -- 64 clocks
+ * 4 -- 128 clocks
+ * 5 -- 256 clocks
+ *
+ * All other values are illegal.
+ *
+ * Bits 09:00 define which REQ/GNT signal pairs get the
+ * GRANT# signal treatment. We set them all.
+ */
+ pci_write_config_word(pdev, 0x50, (5 << 10) | 0x3ff);
+
+ /* The Read Prefecth Policy register is 16-bit and sits at
+ * offset 0x52. It enables a "smart" pre-fetch policy. We
+ * enable it and max out all of the settings since only one
+ * device is sitting underneath and thus bandwidth sharing is
+ * not an issue.
+ *
+ * The register has several 3 bit fields, which indicates a
+ * multiplier applied to the base amount of prefetching the
+ * chip would do. These fields are at:
+ *
+ * 15:13 --- ReRead Primary Bus
+ * 12:10 --- FirstRead Primary Bus
+ * 09:07 --- ReRead Secondary Bus
+ * 06:04 --- FirstRead Secondary Bus
+ *
+ * Bits 03:00 control which REQ/GNT pairs the prefetch settings
+ * get enabled on. Bit 3 is a grouped enabler which controls
+ * all of the REQ/GNT pairs from [8:3]. Bits 2 to 0 control
+ * the individual REQ/GNT pairs [2:0].
+ */
+ pci_write_config_word(pdev, 0x52,
+ (0x7 << 13) |
+ (0x7 << 10) |
+ (0x7 << 7) |
+ (0x7 << 4) |
+ (0xf << 0));
+
+ /* Force cacheline size to 0x8 */
+ pci_write_config_byte(pdev, PCI_CACHE_LINE_SIZE, 0x08);
+
+ /* Force latency timer to maximum setting so Cassini can
+ * sit on the bus as long as it likes.
+ */
+ pci_write_config_byte(pdev, PCI_LATENCY_TIMER, 0xff);
+}
+
static int __devinit cas_init_one(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
@@ -4901,6 +4985,8 @@ static int __devinit cas_init_one(struct pci_dev *pdev,
printk(KERN_WARNING PFX "Could not enable MWI for %s\n",
pci_name(pdev));
+ cas_program_bridge(pdev);
+
/*
* On some architectures, the default cache line size set
* by pci_try_set_mwi reduces perforamnce. We have to increase
--
1.5.4.rc2.17.g257f
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