diff options
Diffstat (limited to 'drivers/gator/gator_buffer.c')
| -rw-r--r-- | drivers/gator/gator_buffer.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/drivers/gator/gator_buffer.c b/drivers/gator/gator_buffer.c new file mode 100644 index 00000000000..eba22dfe3bf --- /dev/null +++ b/drivers/gator/gator_buffer.c @@ -0,0 +1,168 @@ +/** + * Copyright (C) ARM Limited 2010-2014. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +static void marshal_frame(int cpu, int buftype) +{ + int frame; + + if (!per_cpu(gator_buffer, cpu)[buftype]) { + return; + } + + switch (buftype) { + case SUMMARY_BUF: + frame = FRAME_SUMMARY; + break; + case BACKTRACE_BUF: + frame = FRAME_BACKTRACE; + break; + case NAME_BUF: + frame = FRAME_NAME; + break; + case COUNTER_BUF: + frame = FRAME_COUNTER; + break; + case BLOCK_COUNTER_BUF: + frame = FRAME_BLOCK_COUNTER; + break; + case ANNOTATE_BUF: + frame = FRAME_ANNOTATE; + break; + case SCHED_TRACE_BUF: + frame = FRAME_SCHED_TRACE; + break; + case GPU_TRACE_BUF: + frame = FRAME_GPU_TRACE; + break; + case IDLE_BUF: + frame = FRAME_IDLE; + break; + default: + frame = -1; + break; + } + + // add response type + if (gator_response_type > 0) { + gator_buffer_write_packed_int(cpu, buftype, gator_response_type); + } + + // leave space for 4-byte unpacked length + per_cpu(gator_buffer_write, cpu)[buftype] = (per_cpu(gator_buffer_write, cpu)[buftype] + sizeof(s32)) & gator_buffer_mask[buftype]; + + // add frame type and core number + gator_buffer_write_packed_int(cpu, buftype, frame); + gator_buffer_write_packed_int(cpu, buftype, cpu); +} + +static int buffer_bytes_available(int cpu, int buftype) +{ + int remaining, filled; + + filled = per_cpu(gator_buffer_write, cpu)[buftype] - per_cpu(gator_buffer_read, cpu)[buftype]; + if (filled < 0) { + filled += gator_buffer_size[buftype]; + } + + remaining = gator_buffer_size[buftype] - filled; + + if (per_cpu(buffer_space_available, cpu)[buftype]) { + // Give some extra room; also allows space to insert the overflow error packet + remaining -= 200; + } else { + // Hysteresis, prevents multiple overflow messages + remaining -= 2000; + } + + return remaining; +} + +static bool buffer_check_space(int cpu, int buftype, int bytes) +{ + int remaining = buffer_bytes_available(cpu, buftype); + + if (remaining < bytes) { + per_cpu(buffer_space_available, cpu)[buftype] = false; + } else { + per_cpu(buffer_space_available, cpu)[buftype] = true; + } + + return per_cpu(buffer_space_available, cpu)[buftype]; +} + +static int contiguous_space_available(int cpu, int buftype) +{ + int remaining = buffer_bytes_available(cpu, buftype); + int contiguous = gator_buffer_size[buftype] - per_cpu(gator_buffer_write, cpu)[buftype]; + if (remaining < contiguous) + return remaining; + else + return contiguous; +} + +static void gator_commit_buffer(int cpu, int buftype, u64 time) +{ + int type_length, commit, length, byte; + unsigned long flags; + + if (!per_cpu(gator_buffer, cpu)[buftype]) + return; + + // post-populate the length, which does not include the response type length nor the length itself, i.e. only the length of the payload + local_irq_save(flags); + type_length = gator_response_type ? 1 : 0; + commit = per_cpu(gator_buffer_commit, cpu)[buftype]; + length = per_cpu(gator_buffer_write, cpu)[buftype] - commit; + if (length < 0) { + length += gator_buffer_size[buftype]; + } + length = length - type_length - sizeof(s32); + + if (length <= FRAME_HEADER_SIZE) { + // Nothing to write, only the frame header is present + local_irq_restore(flags); + return; + } + + for (byte = 0; byte < sizeof(s32); byte++) { + per_cpu(gator_buffer, cpu)[buftype][(commit + type_length + byte) & gator_buffer_mask[buftype]] = (length >> byte * 8) & 0xFF; + } + + per_cpu(gator_buffer_commit, cpu)[buftype] = per_cpu(gator_buffer_write, cpu)[buftype]; + + if (gator_live_rate > 0) { + while (time > per_cpu(gator_buffer_commit_time, cpu)) { + per_cpu(gator_buffer_commit_time, cpu) += gator_live_rate; + } + } + + marshal_frame(cpu, buftype); + local_irq_restore(flags); + + // had to delay scheduling work as attempting to schedule work during the context switch is illegal in kernel versions 3.5 and greater + if (per_cpu(in_scheduler_context, cpu)) { +#ifndef CONFIG_PREEMPT_RT_FULL + // mod_timer can not be used in interrupt context in RT-Preempt full + mod_timer(&gator_buffer_wake_up_timer, jiffies + 1); +#endif + } else { + up(&gator_buffer_wake_sem); + } +} + +static void buffer_check(int cpu, int buftype, u64 time) +{ + int filled = per_cpu(gator_buffer_write, cpu)[buftype] - per_cpu(gator_buffer_commit, cpu)[buftype]; + if (filled < 0) { + filled += gator_buffer_size[buftype]; + } + if (filled >= ((gator_buffer_size[buftype] * 3) / 4)) { + gator_commit_buffer(cpu, buftype, time); + } +} |