cpu/amd: Add CC6 support

This patch adds CC6 power save support to the AMD Family 15h
support code.  As CC6 is a complex power saving state that
relies heavily on CPU, northbridge, and southbridge cooperation,
this patch alters significant amounts of code throughout the
tree simultaneously.

Allowing the CPU to enter CC6 allows the second level of turbo
boost to be reached, and also provides significant power savings
when the system is idle due to the complete core shutdown.

Change-Id: I44ce157cda97fb85f3e8f3d7262d4712b5410670
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/11979
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 80 insertions, 1 deletions

diff --git a/src/northbridge/amd/amdfam10/link_control.c b/src/northbridge/amd/amdfam10/link_control.c
index 1091ef4f2e..7fa9f12b05 100644
--- a/src/northbridge/amd/amdfam10/link_control.c
+++ b/src/northbridge/amd/amdfam10/link_control.c
@@ -49,15 +49,94 @@ static inline uint8_t is_fam15h(void)
 
 static void nb_control_init(struct device *dev)
 {
+	uint8_t enable_c_states;
+	uint8_t enable_cc6;
 	uint32_t dword;
 
 	printk(BIOS_DEBUG, "NB: Function 4 Link Control.. ");
 
+	/* Configure L3 Power Control */
+	dword = pci_read_config32(dev, 0x1c4);
+	dword |= (0x1 << 8);			/* L3PwrSavEn = 1 */
+	pci_write_config32(dev, 0x1c4, dword);
+
 	if (is_fam15h()) {
+		/* Configure L3 Control 2 */
+		dword = pci_read_config32(dev, 0x1cc);
+		dword &= ~(0x7 << 6);			/* ImplRdProjDelayThresh = 0x2 */
+		dword |= (0x2 << 6);
+		pci_write_config32(dev, 0x1cc, dword);
+
+		/* Configure TDP Accumulator Divisor Control */
+		dword = pci_read_config32(dev, 0x104);
+		dword &= ~(0xfff << 2);			/* TdpAccDivRate = 0xc8 */
+		dword |= (0xc8 << 2);
+		dword &= ~0x3;				/* TdpAccDivVal = 0x1 */
+		dword |= 0x1;
+		pci_write_config32(dev, 0x104, dword);
+
+		/* Configure Sample and Residency Timers */
+		dword = pci_read_config32(dev, 0x110);
+		dword &= ~0xfff;			/* CSampleTimer = 0x1 */
+		dword |= 0x1;
+		pci_write_config32(dev, 0x110, dword);
+
+		/* Configure APM TDP Control */
+		dword = pci_read_config32(dev, 0x16c);
+		dword |= (0x1 << 4);			/* ApmTdpLimitIntEn = 1 */
+		pci_write_config32(dev, 0x16c, dword);
+
 		/* Enable APM */
 		dword = pci_read_config32(dev, 0x15c);
 		dword |= (0x1 << 7);			/* ApmMasterEn = 1 */
 		pci_write_config32(dev, 0x15c, dword);
+
+		enable_c_states = 0;
+		enable_cc6 = 0;
+#if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+		uint8_t nvram;
+
+		if (get_option(&nvram, "cpu_c_states") == CB_SUCCESS)
+			enable_c_states = !!nvram;
+
+		if (get_option(&nvram, "cpu_cc6_state") == CB_SUCCESS)
+			enable_cc6 = !!nvram;
+#endif
+
+		if (enable_c_states) {
+			/* Configure C-state Control 1 */
+			dword = pci_read_config32(dev, 0x118);
+			dword |= (0x1 << 24);		/* PwrGateEnCstAct1 = 1 */
+			dword &= ~(0x7 << 21);		/* ClkDivisorCstAct1 = 0x0 */
+			dword &= ~(0x3 << 18);		/* CacheFlushTmrSelCstAct1 = 0x1 */
+			dword |= (0x1 << 18);
+			dword |= (0x1 << 17);		/* CacheFlushEnCstAct1 = 1 */
+			dword |= (0x1 << 16);		/* CpuPrbEnCstAct1 = 1 */
+			dword &= ~(0x1 << 8);		/* PwrGateEnCstAct0 = 0 */
+			dword &= ~(0x7 << 5);		/* ClkDivisorCstAct0 = 0x0 */
+			dword &= ~(0x3 << 2);		/* CacheFlushTmrSelCstAct0 = 0x2 */
+			dword |= (0x2 << 2);
+			dword |= (0x1 << 1);		/* CacheFlushEnCstAct0 = 1 */
+			dword |= 0x1;			/* CpuPrbEnCstAct0 = 1 */
+			pci_write_config32(dev, 0x118, dword);
+
+			/* Configure C-state Control 2 */
+			dword = pci_read_config32(dev, 0x11c);
+			dword &= ~(0x1 << 8);		/* PwrGateEnCstAct2 = 0 */
+			dword &= ~(0x7 << 5);		/* ClkDivisorCstAct2 = 0x0 */
+			dword &= ~(0x3 << 2);		/* CacheFlushTmrSelCstAct0 = 0x0 */
+			dword &= ~(0x1 << 1);		/* CacheFlushEnCstAct0 = 0 */
+			dword &= ~(0x1);		/* CpuPrbEnCstAct0 = 0 */
+			pci_write_config32(dev, 0x11c, dword);
+
+			/* Configure C-state Policy Control 1 */
+			dword = pci_read_config32(dev, 0x128);
+			dword &= ~(0x7f << 5);		/* CacheFlushTmr = 0x28 */
+			dword |= (0x28 << 5);
+			dword &= ~0x1;			/* CoreCstateMode = !enable_cc6 */
+			dword |= ((enable_cc6)?0:1);
+			pci_write_config32(dev, 0x128, dword);
+		}
 	}
 
 	printk(BIOS_DEBUG, "done.\n");
@@ -83,4 +162,4 @@ static const struct pci_driver mcf4_driver_fam15 __pci_driver = {
 	.ops    = &mcf4_ops,
 	.vendor = PCI_VENDOR_ID_AMD,
 	.device = 0x1604,
-};
\ No newline at end of file
+};