summaryrefslogtreecommitdiff
path: root/src/southbridge/intel/i82801cx/early_smbus.c
diff options
context:
space:
mode:
authorstepan <stepan@coresystems.de>2010-12-08 05:42:47 +0000
committerStefan Reinauer <stepan@openbios.org>2010-12-08 05:42:47 +0000
commit836ae29ee325b1e3d28ff59468cc50913b1e24ce (patch)
treee2691a1e1ee1d795ffe7a99fb93778a9910044c2 /src/southbridge/intel/i82801cx/early_smbus.c
parent1bc5ccac51d94cfb4f9666ecf2cac619d8dc80a6 (diff)
first round name simplification. drop the <component>_ prefix.
the prefix was introduced in the early v2 tree many years ago because our old build system "newconfig" could not handle two files with the same name in different paths like /path/to/usb.c and /another/path/to/usb.c correctly. Only one of the files would end up being compiled into the final image. Since Kconfig (actually since shortly before we switched to Kconfig) we don't suffer from that problem anymore. So we could drop the sb700_ prefix from all those filenames (or, the <componentname>_ prefix in general) - makes it easier to fork off a new chipset - makes it easier to diff against other chipsets - storing redundant information in filenames seems wrong Signed-off-by: <stepan@coresystems.de> Acked-by: Patrick Georgi <patrick@georgi-clan.de> Acked-by: Peter Stuge <peter@stuge.se> git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6149 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1
Diffstat (limited to 'src/southbridge/intel/i82801cx/early_smbus.c')
-rw-r--r--src/southbridge/intel/i82801cx/early_smbus.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/src/southbridge/intel/i82801cx/early_smbus.c b/src/southbridge/intel/i82801cx/early_smbus.c
new file mode 100644
index 0000000000..b62db80f9c
--- /dev/null
+++ b/src/southbridge/intel/i82801cx/early_smbus.c
@@ -0,0 +1,134 @@
+#include <device/pci_ids.h>
+#include "i82801cx.h"
+
+static void enable_smbus(void)
+{
+ device_t dev = PCI_DEV(0x0, 0x1f, 0x3);
+
+ print_debug("SMBus controller enabled\n");
+ /* set smbus iobase */
+ pci_write_config32(dev, SMB_BASE, SMBUS_IO_BASE | PCI_BASE_ADDRESS_SPACE_IO);
+ /* Set smbus enable */
+ pci_write_config8(dev, HOSTC, HST_EN);
+ /* Set smbus iospace enable */
+ pci_write_config16(dev, PCI_COMMAND, PCI_COMMAND_IO);
+ /* Disable interrupt generation */
+ outb(0, SMBUS_IO_BASE + SMBHSTCTL);
+ /* clear any lingering errors, so the transaction will run */
+ outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
+}
+
+
+static inline void smbus_delay(void)
+{
+ outb(0x80, 0x80);
+}
+
+// See http://www.coreboot.org/pipermail/linuxbios/2004-September/009077.html
+// for a description of this function.
+static int smbus_wait_until_active(void)
+{
+ unsigned long loops;
+ loops = SMBUS_TIMEOUT;
+ do {
+ unsigned char val;
+ smbus_delay();
+ val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+ if ((val & 1)) {
+ break;
+ }
+ } while (--loops);
+ return loops ? 0 : -4;
+}
+
+static int smbus_wait_until_ready(void)
+{
+ unsigned long loops;
+ loops = SMBUS_TIMEOUT;
+ do {
+ unsigned char val;
+ smbus_delay();
+ val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+ // !HOST_BUSY?
+ if ((val & 1) == 0) {
+ break;
+ }
+ if(loops == (SMBUS_TIMEOUT / 2)) {
+ // Clear status flags
+ outb(inb(SMBUS_IO_BASE + SMBHSTSTAT),
+ SMBUS_IO_BASE + SMBHSTSTAT);
+ }
+ } while(--loops);
+ return loops?0:-2;
+}
+
+static int smbus_wait_until_done(void)
+{
+ unsigned long loops;
+ loops = SMBUS_TIMEOUT;
+ do {
+ unsigned char val;
+ smbus_delay();
+
+ val = inb(SMBUS_IO_BASE + SMBHSTSTAT);
+ // !HOST_BUSY?
+ if ( (val & 1) == 0) {
+ break;
+ }
+ // BYTE_DONE or SUCCESS or error?
+ if ((val & ~((1<<6)|(1<<0)) ) != 0 ) {
+ break;
+ }
+ } while(--loops);
+ return loops?0:-3;
+}
+
+static int smbus_read_byte(unsigned device, unsigned address)
+{
+ unsigned char global_control_register;
+ unsigned char global_status_register;
+ unsigned char byte;
+
+ if (smbus_wait_until_ready() < 0) {
+ return -2;
+ }
+
+ /* setup transaction */
+ /* disable interrupts */
+ outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xfe, SMBUS_IO_BASE + SMBHSTCTL);
+ /* set to read from the specified device */
+ outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBXMITADD);
+ /* set the command/address... */
+ outb(address & 0xFF, SMBUS_IO_BASE + SMBHSTCMD);
+ /* set up for a byte data read */
+ outb((inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xe3) | (0x2<<2), SMBUS_IO_BASE + SMBHSTCTL);
+
+ /* clear any lingering errors, so the transaction will run */
+ outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT);
+
+ /* clear the data byte...*/
+ outb(0, SMBUS_IO_BASE + SMBHSTDAT0);
+
+ /* start a byte read, with interrupts disabled */
+ outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40), SMBUS_IO_BASE + SMBHSTCTL);
+ /* poll for it to start */
+ if (smbus_wait_until_active() < 0) {
+ return -4;
+ }
+
+ /* poll for transaction completion */
+ if (smbus_wait_until_done() < 0) {
+ return -3;
+ }
+
+ global_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT) & ~(1<<6); /* Ignore the In Use Status... */
+
+ /* read results of transaction */
+ byte = inb(SMBUS_IO_BASE + SMBHSTDAT0);
+
+ // SUCCESS?
+ if (global_status_register != 2) {
+ return -1;
+ }
+ return byte;
+}