diff options
Diffstat (limited to 'docs/pmu_support.md')
| -rw-r--r-- | docs/pmu_support.md | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/docs/pmu_support.md b/docs/pmu_support.md index a60b75c..7e3367c 100644 --- a/docs/pmu_support.md +++ b/docs/pmu_support.md @@ -50,12 +50,20 @@ event-to-mhpmevent is present. Otherwise, it can be omitted. This property shouldn't encode any raw event. * **riscv,raw-event-to-mhpmcounters**(Optional) - It represents an ONE-to-MANY -mapping between a raw event and all the MHPMCOUNTERx in a bitmap format that can -be used to monitor that raw event. The information is encoded in a table format -where each raw represent a specific raw event. The first column stores the -expected event selector value that should be encoded in the expected value to be -written in MHPMEVENTx. The second column stores a bitmap of all the MHPMCOUNTERx -that can be used for monitoring the specified event. +or MANY-to-MANY mapping between the raw event(s) and all the MHPMCOUNTERx in +a bitmap format that can be used to monitor that raw event, which depends on +how the platform encodes the monitor events. Currently, only the following three +encoding methods are supported, encoding each event as a number, using a bitmap +to encode monitor events, and mixing the previous two methods. The information +is encoded in a table format where each row represent the specific raw event(s). +The first column represents a 64-bit selector value which can indicate an +monitor event ID (encoded by a number) or an event set (encoded by a bitmap). +In case of the latter, the lower bits used to encode a set of events should be +set to zero. The second column is a 64-bit selector mask where any bits used +for event encoding will be cleared. If a platform directly encodes each raw PMU +event as a unique ID, the value of select_mask will be 0xffffffff_ffffffff. +The third column represent a bitmap of all the MHPMCOUNTERx that can be used for +monitoring the specified event(s). *Note:* A platform may choose to provide the mapping between event & counters via platform hooks rather than the device tree. @@ -72,8 +80,8 @@ pmu { <0x00002 0x00002 0x00000004>, <0x00003 0x0000A 0x00000ff8>, <0x10000 0x10033 0x000ff000>, - riscv,raw-event-to-mhpmcounters = <0x0000 0x0002 0x00000f8>, - <0x0000 0x0003 0x00000ff0>, + riscv,raw-event-to-mhpmcounters = <0x0000 0x0002 0xffffffff 0xffffffff 0x00000f8>, + <0xffffffff 0xfffffff0 0xffffffff 0xfffffff0 0x00000ff0>, }; ``` |