diff options
| -rw-r--r-- | 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 9c77eadb676..33ac2ef6777 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 |