[U-Boot] [PATCH v3 01/26] x86: Allow timer calibration to work on ivybridge

[Simon Glass]

Unfortunately MSR_FSB_FREQ is not available on this CPU, and the PIT method
seems to take up to 50ms which is much too long.

For this CPU we know the frequency, so add another special case for now.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

Changes in v3:
- Try another approach for fixing the timer

Changes in v2:
- Add new patch to tidy up timer code for Intel core architecture

 arch/x86/lib/tsc_timer.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/arch/x86/lib/tsc_timer.c b/arch/x86/lib/tsc_timer.c
index f091c91..fb9afed 100644
--- a/arch/x86/lib/tsc_timer.c
+++ b/arch/x86/lib/tsc_timer.c
@@ -36,7 +36,8 @@ DECLARE_GLOBAL_DATA_PTR;
 struct freq_desc {
 	u8 x86_family;	/* CPU family */
 	u8 x86_model;	/* model */
-	u8 msr_plat;	/* 1: use MSR_PLATFORM_INFO, 0: MSR_IA32_PERF_STATUS */
+	/* 2: use 100MHz, 1: use MSR_PLATFORM_INFO, 0: MSR_IA32_PERF_STATUS */
+	u8 msr_plat;
 	u32 freqs[MAX_NUM_FREQS];
 };
 
@@ -49,6 +50,8 @@ static struct freq_desc freq_desc_tables[] = {
 	{ 6, 0x4a, 1, { 0, FREQ_100, FREQ_133, 0, 0, 0, 0, 0 } },
 	/* VLV2 */
 	{ 6, 0x37, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_166, 0, 0, 0, 0 } },
+	/* Ivybridge */
+	{ 6, 0x3a, 2, { 0, 0, 0, 0, 0, 0, 0, 0 } },
 	/* ANN */
 	{ 6, 0x5a, 1, { FREQ_83, FREQ_100, FREQ_133, FREQ_100, 0, 0, 0, 0 } },
 };
@@ -97,11 +100,18 @@ static unsigned long try_msr_calibrate_tsc(void)
 	if (!ratio)
 		goto fail;
 
-	/* Get FSB FREQ ID */
-	rdmsr(MSR_FSB_FREQ, lo, hi);
-	freq_id = lo & 0x7;
-	freq = id_to_freq(cpu_index, freq_id);
-	debug("Resolved frequency ID: %u, frequency: %u KHz\n", freq_id, freq);
+	if (freq_desc_tables[cpu_index].msr_plat == 2) {
+		/* TODO: Figure out how best to deal with this */
+		freq = FREQ_100;
+		debug("Using frequency: %u KHz\n", freq);
+	} else {
+		/* Get FSB FREQ ID */
+		rdmsr(MSR_FSB_FREQ, lo, hi);
+		freq_id = lo & 0x7;
+		freq = id_to_freq(cpu_index, freq_id);
+		debug("Resolved frequency ID: %u, frequency: %u KHz\n",
+		      freq_id, freq);
+	}
 	if (!freq)
 		goto fail;
 
@@ -297,12 +307,12 @@ unsigned __attribute__((no_instrument_function)) long get_tbclk_mhz(void)
 		return gd->arch.tsc_mhz;
 
 	fast_calibrate = try_msr_calibrate_tsc();
-	if (fast_calibrate)
-		return fast_calibrate;
+	if (!fast_calibrate) {
 
-	fast_calibrate = quick_pit_calibrate();
-	if (!fast_calibrate)
-		panic("TSC frequency is ZERO");
+		fast_calibrate = quick_pit_calibrate();
+		if (!fast_calibrate)
+			panic("TSC frequency is ZERO");
+	}
 
 	gd->arch.tsc_mhz = fast_calibrate;
 	return fast_calibrate;
-- 
2.1.0.rc2.206.gedb03e5