x86: Allow timer calibration to work on ivybridge

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@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

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;