From bc3fc26e3489722d2313aa777c11b2a649549e5b Mon Sep 17 00:00:00 2001
From: Robert Jordens <rj@m-labs.hk>
Date: Sun, 12 Feb 2017 15:33:25 +0100
Subject: [PATCH] coredevice: expose PCU

---
 artiq/coredevice/pcu.py        | 72 ++++++++++++++++++++++++++++++++++
 artiq/coredevice/spr.py        | 12 ++++++
 artiq/firmware/ksupport/api.rs |  3 ++
 3 files changed, 87 insertions(+)
 create mode 100644 artiq/coredevice/pcu.py
 create mode 100644 artiq/coredevice/spr.py

diff --git a/artiq/coredevice/pcu.py b/artiq/coredevice/pcu.py
new file mode 100644
index 000000000..e819aa239
--- /dev/null
+++ b/artiq/coredevice/pcu.py
@@ -0,0 +1,72 @@
+from .spr import mtspr, mfspr
+from artiq.language.core import kernel
+
+
+_MAX_SPRS_PER_GRP_BITS = 11
+_SPRGROUP_PC = 7 << _MAX_SPRS_PER_GRP_BITS
+_SPR_PCMR_CP    = 0x00000001  # Counter present
+_SPR_PCMR_CISM  = 0x00000004  # Count in supervisor mode
+_SPR_PCMR_CIUM  = 0x00000008  # Count in user mode
+_SPR_PCMR_LA    = 0x00000010  # Load access event
+_SPR_PCMR_SA    = 0x00000020  # Store access event
+_SPR_PCMR_IF    = 0x00000040  # Instruction fetch event
+_SPR_PCMR_DCM   = 0x00000080  # Data cache miss event
+_SPR_PCMR_ICM   = 0x00000100  # Insn cache miss event
+_SPR_PCMR_IFS   = 0x00000200  # Insn fetch stall event
+_SPR_PCMR_LSUS  = 0x00000400  # LSU stall event
+_SPR_PCMR_BS    = 0x00000800  # Branch stall event
+_SPR_PCMR_DTLBM = 0x00001000  # DTLB miss event
+_SPR_PCMR_ITLBM = 0x00002000  # ITLB miss event
+_SPR_PCMR_DDS   = 0x00004000  # Data dependency stall event
+_SPR_PCMR_WPE   = 0x03ff8000  # Watchpoint events
+
+
+@kernel(flags={"nowrite", "nounwind"})
+def _PCCR(n):
+    return _SPRGROUP_PC + n
+
+
+@kernel(flags={"nowrite", "nounwind"})
+def _PCMR(n):
+    return _SPRGROUP_PC + 8 + n
+
+
+@kernel
+def pc_start():
+    """
+    Configure and clear the kernel CPU performance counters.
+
+    The eight counters are configures to count the folloging events:
+        * Load or store
+        * Instruction fetch
+        * Data cache miss
+        * Instruction cache miss
+        * Instruction fetch stall
+        * Load-store-unit stall
+        * Branch stall
+        * Data dependency stall
+    """
+    for i in range(8):
+        if not mfspr(_PCMR(i)) & _SPR_PCMR_CP:
+            raise ValueError("counter not present")
+        mtspr(_PCMR(i), 0)
+        mtspr(_PCCR(i), 0)
+    mtspr(_PCMR(0), _SPR_PCMR_CISM | _SPR_PCMR_LA | _SPR_PCMR_SA)
+    mtspr(_PCMR(1), _SPR_PCMR_CISM | _SPR_PCMR_IF)
+    mtspr(_PCMR(2), _SPR_PCMR_CISM | _SPR_PCMR_DCM)
+    mtspr(_PCMR(3), _SPR_PCMR_CISM | _SPR_PCMR_ICM)
+    mtspr(_PCMR(4), _SPR_PCMR_CISM | _SPR_PCMR_IFS)
+    mtspr(_PCMR(5), _SPR_PCMR_CISM | _SPR_PCMR_LSUS)
+    mtspr(_PCMR(6), _SPR_PCMR_CISM | _SPR_PCMR_BS)
+    mtspr(_PCMR(7), _SPR_PCMR_CISM | _SPR_PCMR_DDS)
+
+
+@kernel
+def pc_get(r):
+    """
+    Read the performance counters and store the counts in the array provided.
+
+    :param list[int] r: array to store the counter values
+    """
+    for i in range(8):
+        r[i] = mfspr(_PCCR(i))
diff --git a/artiq/coredevice/spr.py b/artiq/coredevice/spr.py
new file mode 100644
index 000000000..4f968d794
--- /dev/null
+++ b/artiq/coredevice/spr.py
@@ -0,0 +1,12 @@
+from artiq.language.core import syscall
+from artiq.language.types import TInt32, TNone
+
+
+@syscall(flags={"nounwind", "nowrite"})
+def mfspr(spr: TInt32) -> TInt32:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall(flags={"nowrite", "nowrite"})
+def mtspr(spr: TInt32, value: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
diff --git a/artiq/firmware/ksupport/api.rs b/artiq/firmware/ksupport/api.rs
index a38d17f9a..ce07c5aa4 100644
--- a/artiq/firmware/ksupport/api.rs
+++ b/artiq/firmware/ksupport/api.rs
@@ -94,6 +94,9 @@ static mut API: &'static [(&'static str, *const ())] = &[
     api!(cache_get = ::cache_get),
     api!(cache_put = ::cache_put),
 
+    api!(mfspr = ::board::spr::mfspr),
+    api!(mtspr = ::board::spr::mtspr),
+
     /* direct syscalls */
     api!(rtio_init = ::rtio::init),
     api!(rtio_get_counter = ::rtio::get_counter),