x86/platform/intel-mid: Remove custom TSC calibration

Since the commit

  7da7c1561366 ("x86, tsc: Add static (MSR) TSC calibration on Intel Atom SoCs")

introduced a common way for all Intel MID chips to get their TSC frequency
via MSRs, there is no need to keep a duplication in each of Intel MID
platform code.

Thus, remove the custom calibration code for good.

Note, there is slight difference in how to get frequency for (reserved?)
values in MSRs, i.e. legacy code enforces some defaults while new code just
uses 0 in that cases.

Suggested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Bin Gao <bin.gao@intel.com>
Link: https://lkml.kernel.org/r/20180629193113.84425-6-andriy.shevchenko@linux.intel.com

arch/x86/include/asm/intel-mid.h

@@ -136,20 +136,6 @@ enum intel_mid_timer_options {
 
 extern enum intel_mid_timer_options intel_mid_timer_options;
 
-/*
- * Penwell uses spread spectrum clock, so the freq number is not exactly
- * the same as reported by MSR based on SDM.
- */
-#define FSB_FREQ_83SKU			83200
-#define FSB_FREQ_100SKU			99840
-#define FSB_FREQ_133SKU			133000
-
-#define FSB_FREQ_167SKU			167000
-#define FSB_FREQ_200SKU			200000
-#define FSB_FREQ_267SKU			267000
-#define FSB_FREQ_333SKU			333000
-#define FSB_FREQ_400SKU			400000
-
 /* Bus Select SoC Fuse value */
 #define BSEL_SOC_FUSE_MASK		0x7
 /* FSB 133MHz */

arch/x86/kernel/tsc_msr.c

@@ -29,6 +29,11 @@ struct freq_desc {
 	u32 freqs[MAX_NUM_FREQS];
 };
 
+/*
+ * Penwell and Clovertrail use spread spectrum clock,
+ * so the freq number is not exactly the same as reported
+ * by MSR based on SDM.
+ */
 static const struct freq_desc freq_desc_pnw = {
 	0, { 0, 0, 0, 0, 0, 99840, 0, 83200 }
 };

arch/x86/platform/intel-mid/intel-mid.c

@@ -82,11 +82,6 @@ static void intel_mid_reboot(void)
 	intel_scu_ipc_simple_command(IPCMSG_COLD_RESET, 0);
 }
 
-static unsigned long __init intel_mid_calibrate_tsc(void)
-{
-	return 0;
-}
-
 static void __init intel_mid_setup_bp_timer(void)
 {
 	apbt_time_init();
@@ -191,7 +186,6 @@ void __init x86_intel_mid_early_setup(void)
 
 	x86_cpuinit.setup_percpu_clockev = apbt_setup_secondary_clock;
 
-	x86_platform.calibrate_tsc = intel_mid_calibrate_tsc;
 	x86_platform.get_nmi_reason = intel_mid_get_nmi_reason;
 
 	x86_init.pci.arch_init = intel_mid_pci_init;

arch/x86/platform/intel-mid/mfld.c

@@ -11,48 +11,12 @@
 
 #include <linux/init.h>
 
-#include <asm/apic.h>
 #include <asm/intel-mid.h>
-#include <asm/intel_mid_vrtc.h>
 
 #include "intel_mid_weak_decls.h"
 
-static unsigned long __init mfld_calibrate_tsc(void)
-{
-	unsigned long fast_calibrate;
-	u32 lo, hi, ratio, fsb;
-
-	rdmsr(MSR_IA32_PERF_STATUS, lo, hi);
-	pr_debug("IA32 perf status is 0x%x, 0x%0x\n", lo, hi);
-	ratio = (hi >> 8) & 0x1f;
-	pr_debug("ratio is %d\n", ratio);
-	if (!ratio) {
-		pr_err("read a zero ratio, should be incorrect!\n");
-		pr_err("force tsc ratio to 16 ...\n");
-		ratio = 16;
-	}
-	rdmsr(MSR_FSB_FREQ, lo, hi);
-	if ((lo & 0x7) == 0x7)
-		fsb = FSB_FREQ_83SKU;
-	else
-		fsb = FSB_FREQ_100SKU;
-	fast_calibrate = ratio * fsb;
-	pr_debug("read penwell tsc %lu khz\n", fast_calibrate);
-	lapic_timer_frequency = fsb * 1000 / HZ;
-
-	/*
-	 * TSC on Intel Atom SoCs is reliable and of known frequency.
-	 * See tsc_msr.c for details.
-	 */
-	setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
-	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
-
-	return fast_calibrate;
-}
-
 static void __init penwell_arch_setup(void)
 {
-	x86_platform.calibrate_tsc = mfld_calibrate_tsc;
 }
 
 static struct intel_mid_ops penwell_ops = {

arch/x86/platform/intel-mid/mrfld.c

@@ -11,86 +11,12 @@
 
 #include <linux/init.h>
 
-#include <asm/apic.h>
 #include <asm/intel-mid.h>
 
 #include "intel_mid_weak_decls.h"
 
-static unsigned long __init tangier_calibrate_tsc(void)
-{
-	unsigned long fast_calibrate;
-	u32 lo, hi, ratio, fsb, bus_freq;
-
-	/* *********************** */
-	/* Compute TSC:Ratio * FSB */
-	/* *********************** */
-
-	/* Compute Ratio */
-	rdmsr(MSR_PLATFORM_INFO, lo, hi);
-	pr_debug("IA32 PLATFORM_INFO is 0x%x : %x\n", hi, lo);
-
-	ratio = (lo >> 8) & 0xFF;
-	pr_debug("ratio is %d\n", ratio);
-	if (!ratio) {
-		pr_err("Read a zero ratio, force tsc ratio to 4 ...\n");
-		ratio = 4;
-	}
-
-	/* Compute FSB */
-	rdmsr(MSR_FSB_FREQ, lo, hi);
-	pr_debug("Actual FSB frequency detected by SOC 0x%x : %x\n",
-			hi, lo);
-
-	bus_freq = lo & 0x7;
-	pr_debug("bus_freq = 0x%x\n", bus_freq);
-
-	if (bus_freq == 0)
-		fsb = FSB_FREQ_100SKU;
-	else if (bus_freq == 1)
-		fsb = FSB_FREQ_100SKU;
-	else if (bus_freq == 2)
-		fsb = FSB_FREQ_133SKU;
-	else if (bus_freq == 3)
-		fsb = FSB_FREQ_167SKU;
-	else if (bus_freq == 4)
-		fsb = FSB_FREQ_83SKU;
-	else if (bus_freq == 5)
-		fsb = FSB_FREQ_400SKU;
-	else if (bus_freq == 6)
-		fsb = FSB_FREQ_267SKU;
-	else if (bus_freq == 7)
-		fsb = FSB_FREQ_333SKU;
-	else {
-		BUG();
-		pr_err("Invalid bus_freq! Setting to minimal value!\n");
-		fsb = FSB_FREQ_100SKU;
-	}
-
-	/* TSC = FSB Freq * Resolved HFM Ratio */
-	fast_calibrate = ratio * fsb;
-	pr_debug("calculate tangier tsc %lu KHz\n", fast_calibrate);
-
-	/* ************************************ */
-	/* Calculate Local APIC Timer Frequency */
-	/* ************************************ */
-	lapic_timer_frequency = (fsb * 1000) / HZ;
-
-	pr_debug("Setting lapic_timer_frequency = %d\n",
-			lapic_timer_frequency);
-
-	/*
-	 * TSC on Intel Atom SoCs is reliable and of known frequency.
-	 * See tsc_msr.c for details.
-	 */
-	setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
-	setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
-
-	return fast_calibrate;
-}
-
 static void __init tangier_arch_setup(void)
 {
-	x86_platform.calibrate_tsc = tangier_calibrate_tsc;
 	x86_platform.legacy.rtc = 1;
 }