Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 202 insertions, 0 deletions

diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c
new file mode 100644
index 000000000..012d5614e
--- /dev/null
+++ b/lib/flex_proportions.c
@@ -0,0 +1,202 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Floating proportions with flexible aging period
+ *
+ *   Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
+ *
+ * The goal of this code is: Given different types of event, measure proportion
+ * of each type of event over time. The proportions are measured with
+ * exponentially decaying history to give smooth transitions. A formula
+ * expressing proportion of event of type 'j' is:
+ *
+ *   p_{j} = (\Sum_{i>=0} x_{i,j}/2^{i+1})/(\Sum_{i>=0} x_i/2^{i+1})
+ *
+ * Where x_{i,j} is j's number of events in i-th last time period and x_i is
+ * total number of events in i-th last time period.
+ *
+ * Note that p_{j}'s are normalised, i.e.
+ *
+ *   \Sum_{j} p_{j} = 1,
+ *
+ * This formula can be straightforwardly computed by maintaining denominator
+ * (let's call it 'd') and for each event type its numerator (let's call it
+ * 'n_j'). When an event of type 'j' happens, we simply need to do:
+ *   n_j++; d++;
+ *
+ * When a new period is declared, we could do:
+ *   d /= 2
+ *   for each j
+ *     n_j /= 2
+ *
+ * To avoid iteration over all event types, we instead shift numerator of event
+ * j lazily when someone asks for a proportion of event j or when event j
+ * occurs. This can bit trivially implemented by remembering last period in
+ * which something happened with proportion of type j.
+ */
+#include <linux/flex_proportions.h>
+
+int fprop_global_init(struct fprop_global *p, gfp_t gfp)
+{
+	int err;
+
+	p->period = 0;
+	/* Use 1 to avoid dealing with periods with 0 events... */
+	err = percpu_counter_init(&p->events, 1, gfp);
+	if (err)
+		return err;
+	seqcount_init(&p->sequence);
+	return 0;
+}
+
+void fprop_global_destroy(struct fprop_global *p)
+{
+	percpu_counter_destroy(&p->events);
+}
+
+/*
+ * Declare @periods new periods. It is upto the caller to make sure period
+ * transitions cannot happen in parallel.
+ *
+ * The function returns true if the proportions are still defined and false
+ * if aging zeroed out all events. This can be used to detect whether declaring
+ * further periods has any effect.
+ */
+bool fprop_new_period(struct fprop_global *p, int periods)
+{
+	s64 events = percpu_counter_sum(&p->events);
+	unsigned long flags;
+
+	/*
+	 * Don't do anything if there are no events.
+	 */
+	if (events <= 1)
+		return false;
+	local_irq_save(flags);
+	write_seqcount_begin(&p->sequence);
+	if (periods < 64)
+		events -= events >> periods;
+	/* Use addition to avoid losing events happening between sum and set */
+	percpu_counter_add(&p->events, -events);
+	p->period += periods;
+	write_seqcount_end(&p->sequence);
+	local_irq_restore(flags);
+
+	return true;
+}
+
+/*
+ * ---- PERCPU ----
+ */
+#define PROP_BATCH (8*(1+ilog2(nr_cpu_ids)))
+
+int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp)
+{
+	int err;
+
+	err = percpu_counter_init(&pl->events, 0, gfp);
+	if (err)
+		return err;
+	pl->period = 0;
+	raw_spin_lock_init(&pl->lock);
+	return 0;
+}
+
+void fprop_local_destroy_percpu(struct fprop_local_percpu *pl)
+{
+	percpu_counter_destroy(&pl->events);
+}
+
+static void fprop_reflect_period_percpu(struct fprop_global *p,
+					struct fprop_local_percpu *pl)
+{
+	unsigned int period = p->period;
+	unsigned long flags;
+
+	/* Fast path - period didn't change */
+	if (pl->period == period)
+		return;
+	raw_spin_lock_irqsave(&pl->lock, flags);
+	/* Someone updated pl->period while we were spinning? */
+	if (pl->period >= period) {
+		raw_spin_unlock_irqrestore(&pl->lock, flags);
+		return;
+	}
+	/* Aging zeroed our fraction? */
+	if (period - pl->period < BITS_PER_LONG) {
+		s64 val = percpu_counter_read(&pl->events);
+
+		if (val < (nr_cpu_ids * PROP_BATCH))
+			val = percpu_counter_sum(&pl->events);
+
+		percpu_counter_add_batch(&pl->events,
+			-val + (val >> (period-pl->period)), PROP_BATCH);
+	} else
+		percpu_counter_set(&pl->events, 0);
+	pl->period = period;
+	raw_spin_unlock_irqrestore(&pl->lock, flags);
+}
+
+/* Event of type pl happened */
+void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,
+		long nr)
+{
+	fprop_reflect_period_percpu(p, pl);
+	percpu_counter_add_batch(&pl->events, nr, PROP_BATCH);
+	percpu_counter_add(&p->events, nr);
+}
+
+void fprop_fraction_percpu(struct fprop_global *p,
+			   struct fprop_local_percpu *pl,
+			   unsigned long *numerator, unsigned long *denominator)
+{
+	unsigned int seq;
+	s64 num, den;
+
+	do {
+		seq = read_seqcount_begin(&p->sequence);
+		fprop_reflect_period_percpu(p, pl);
+		num = percpu_counter_read_positive(&pl->events);
+		den = percpu_counter_read_positive(&p->events);
+	} while (read_seqcount_retry(&p->sequence, seq));
+
+	/*
+	 * Make fraction <= 1 and denominator > 0 even in presence of percpu
+	 * counter errors
+	 */
+	if (den <= num) {
+		if (num)
+			den = num;
+		else
+			den = 1;
+	}
+	*denominator = den;
+	*numerator = num;
+}
+
+/*
+ * Like __fprop_add_percpu() except that event is counted only if the given
+ * type has fraction smaller than @max_frac/FPROP_FRAC_BASE
+ */
+void __fprop_add_percpu_max(struct fprop_global *p,
+		struct fprop_local_percpu *pl, int max_frac, long nr)
+{
+	if (unlikely(max_frac < FPROP_FRAC_BASE)) {
+		unsigned long numerator, denominator;
+		s64 tmp;
+
+		fprop_fraction_percpu(p, pl, &numerator, &denominator);
+		/* Adding 'nr' to fraction exceeds max_frac/FPROP_FRAC_BASE? */
+		tmp = (u64)denominator * max_frac -
+					((u64)numerator << FPROP_FRAC_SHIFT);
+		if (tmp < 0) {
+			/* Maximum fraction already exceeded? */
+			return;
+		} else if (tmp < nr * (FPROP_FRAC_BASE - max_frac)) {
+			/* Add just enough for the fraction to saturate */
+			nr = div_u64(tmp + FPROP_FRAC_BASE - max_frac - 1,
+					FPROP_FRAC_BASE - max_frac);
+		}
+	}
+
+	__fprop_add_percpu(p, pl, nr);
+}