x86/hpet: Introduce struct hpet_base and struct hpet_channel

Introduce new data structures to replace the ad hoc collection of separate
variables and pointers.

Replace the boot configuration store and restore as a first step.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/20190623132435.728456320@linutronix.de

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index ed2d556..59a81d7 100644 (file)
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -22,6 +22,17 @@ struct hpet_dev {
        char                            name[10];
 };
 
+struct hpet_channel {
+       unsigned int                    num;
+       unsigned int                    boot_cfg;
+};
+
+struct hpet_base {
+       unsigned int                    nr_channels;
+       unsigned int                    boot_cfg;
+       struct hpet_channel             *channels;
+};
+
 #define HPET_MASK                      CLOCKSOURCE_MASK(32)
 
 #define HPET_DEV_USED_BIT              2
@@ -48,7 +59,7 @@ static struct irq_domain              *hpet_domain;
 #endif
 
 static void __iomem                    *hpet_virt_address;
-static u32                             *hpet_boot_cfg;
+static struct hpet_base                        hpet_base;
 
 static bool                            hpet_legacy_int_enabled;
 static unsigned long                   hpet_freq;
@@ -860,6 +871,7 @@ int __init hpet_enable(void)
 {
        u32 hpet_period, cfg, id;
        unsigned int i, channels;
+       struct hpet_channel *hc;
        u64 freq;
 
        if (!is_hpet_capable())
@@ -899,34 +911,39 @@ int __init hpet_enable(void)
        /* This is the HPET channel number which is zero based */
        channels = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
 
-#ifdef CONFIG_HPET_EMULATE_RTC
        /*
         * The legacy routing mode needs at least two channels, tick timer
         * and the rtc emulation channel.
         */
-       if (channels < 2)
+       if (IS_ENABLED(CONFIG_HPET_EMULATE_RTC) && channels < 2)
                goto out_nohpet;
-#endif
 
+       hc = kcalloc(channels, sizeof(*hc), GFP_KERNEL);
+       if (!hc) {
+               pr_warn("Disabling HPET.\n");
+               goto out_nohpet;
+       }
+       hpet_base.channels = hc;
+       hpet_base.nr_channels = channels;
+
+       /* Read, store and sanitize the global configuration */
        cfg = hpet_readl(HPET_CFG);
-       /* Allocate entries for the global and the channel configurations */
-       hpet_boot_cfg = kmalloc_array(channels + 1, sizeof(*hpet_boot_cfg),
-                                     GFP_KERNEL);
-       if (hpet_boot_cfg)
-               *hpet_boot_cfg = cfg;
-       else
-               pr_warn("HPET initial state will not be saved\n");
+       hpet_base.boot_cfg = cfg;
        cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
        hpet_writel(cfg, HPET_CFG);
        if (cfg)
                pr_warn("Global config: Unknown bits %#x\n", cfg);
 
-       for (i = 0; i < channels; ++i) {
+       /* Read, store and sanitize the per channel configuration */
+       for (i = 0; i < channels; i++, hc++) {
+               hc->num = i;
+
                cfg = hpet_readl(HPET_Tn_CFG(i));
-               if (hpet_boot_cfg)
-                       hpet_boot_cfg[i + 1] = cfg;
+               hc->boot_cfg = cfg;
+
                cfg &= ~(HPET_TN_ENABLE | HPET_TN_LEVEL | HPET_TN_FSB);
                hpet_writel(cfg, HPET_Tn_CFG(i));
+
                cfg &= ~(HPET_TN_PERIODIC | HPET_TN_PERIODIC_CAP
                         | HPET_TN_64BIT_CAP | HPET_TN_32BIT | HPET_TN_ROUTE
                         | HPET_TN_FSB | HPET_TN_FSB_CAP);
@@ -944,6 +961,9 @@ int __init hpet_enable(void)
        return 0;
 
 out_nohpet:
+       kfree(hpet_base.channels);
+       hpet_base.channels = NULL;
+       hpet_base.nr_channels = 0;
        hpet_clear_mapping();
        hpet_address = 0;
        return 0;
@@ -1000,30 +1020,24 @@ fs_initcall(hpet_late_init);
 
 void hpet_disable(void)
 {
-       if (is_hpet_capable() && hpet_virt_address) {
-               unsigned int cfg = hpet_readl(HPET_CFG), id, last;
-
-               if (hpet_boot_cfg)
-                       cfg = *hpet_boot_cfg;
-               else if (hpet_legacy_int_enabled) {
-                       cfg &= ~HPET_CFG_LEGACY;
-                       hpet_legacy_int_enabled = false;
-               }
-               cfg &= ~HPET_CFG_ENABLE;
-               hpet_writel(cfg, HPET_CFG);
+       unsigned int i;
+       u32 cfg;
 
-               if (!hpet_boot_cfg)
-                       return;
+       if (!is_hpet_capable() || !hpet_virt_address)
+               return;
 
-               id = hpet_readl(HPET_ID);
-               last = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT);
+       /* Restore boot configuration with the enable bit cleared */
+       cfg = hpet_base.boot_cfg;
+       cfg &= ~HPET_CFG_ENABLE;
+       hpet_writel(cfg, HPET_CFG);
 
-               for (id = 0; id <= last; ++id)
-                       hpet_writel(hpet_boot_cfg[id + 1], HPET_Tn_CFG(id));
+       /* Restore the channel boot configuration */
+       for (i = 0; i < hpet_base.nr_channels; i++)
+               hpet_writel(hpet_base.channels[i].boot_cfg, HPET_Tn_CFG(i));
 
-               if (*hpet_boot_cfg & HPET_CFG_ENABLE)
-                       hpet_writel(*hpet_boot_cfg, HPET_CFG);
-       }
+       /* If the HPET was enabled at boot time, reenable it */
+       if (hpet_base.boot_cfg & HPET_CFG_ENABLE)
+               hpet_writel(hpet_base.boot_cfg, HPET_CFG);
 }
 
 #ifdef CONFIG_HPET_EMULATE_RTC