From patchwork Fri Mar 25 13:49:32 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leon Alrae X-Patchwork-Id: 601994 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3qWl9f2jQcz9s2G for ; Sat, 26 Mar 2016 00:52:38 +1100 (AEDT) Received: from localhost ([::1]:56283 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajSAG-0006gt-K6 for incoming@patchwork.ozlabs.org; Fri, 25 Mar 2016 09:52:36 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38409) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajS7t-0002PQ-US for qemu-devel@nongnu.org; Fri, 25 Mar 2016 09:50:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ajS7r-0002GT-P4 for qemu-devel@nongnu.org; Fri, 25 Mar 2016 09:50:09 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:43931) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajS7r-0002GP-Ic for qemu-devel@nongnu.org; Fri, 25 Mar 2016 09:50:07 -0400 Received: from hhmail02.hh.imgtec.org (unknown [10.100.10.20]) by Websense Email Security Gateway with ESMTPS id B3ABDD295C971; Fri, 25 Mar 2016 13:50:03 +0000 (GMT) Received: from lalrae-linux.kl.imgtec.org (192.168.169.37) by hhmail02.hh.imgtec.org (10.100.10.20) with Microsoft SMTP Server (TLS) id 14.3.266.1; Fri, 25 Mar 2016 13:50:06 +0000 From: Leon Alrae To: Date: Fri, 25 Mar 2016 13:49:32 +0000 Message-ID: <1458913777-28034-4-git-send-email-leon.alrae@imgtec.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1458913777-28034-1-git-send-email-leon.alrae@imgtec.com> References: <1458913777-28034-1-git-send-email-leon.alrae@imgtec.com> MIME-Version: 1.0 X-Originating-IP: [192.168.169.37] X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 195.59.15.196 Cc: aurelien@aurel32.net Subject: [Qemu-devel] [PATCH v2 3/8] hw/mips: implement ITC Storage - Empty/Full Sync and Try Views X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Empty/Full Synchronized and Try views can be used to access FIFO cells. Store to the FIFO cell pushes the value into the queue, load pops the oldest element from the queue. Cell's Full and Empty bits are automatically updated to reflect new state of the cell. Empty/Full Synchronized View causes the issuing thread to block when FIFO is empty while thread is performing a read, or FIFO is full while thread is performing a write. Empty/Full Try View never blocks the thread. If cell is full then write is ignored, if cell is empty then load returns 0. Trap bit (i.e. Gating Storage exceptions) not implemented. Store Conditional support for E/F Try View (i.e. indicate failure if FIFO is full) not implemented. Signed-off-by: Leon Alrae --- hw/misc/mips_itu.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) diff --git a/hw/misc/mips_itu.c b/hw/misc/mips_itu.c index 742656d..ae59ae4 100644 --- a/hw/misc/mips_itu.c +++ b/hw/misc/mips_itu.c @@ -159,6 +159,26 @@ static inline ITCStorageCell *get_cell(MIPSITUState *s, return &s->cell[cell_idx]; } +static void wake_blocked_threads(ITCStorageCell *c) +{ + CPUState *cs; + CPU_FOREACH(cs) { + if (cs->halted && (c->blocked_threads & (1ULL << cs->cpu_index))) { + cpu_interrupt(cs, CPU_INTERRUPT_WAKE); + } + } + c->blocked_threads = 0; +} + +static void QEMU_NORETURN block_thread_and_exit(ITCStorageCell *c) +{ + c->blocked_threads |= 1ULL << current_cpu->cpu_index; + cpu_restore_state(current_cpu, current_cpu->mem_io_pc); + current_cpu->halted = 1; + current_cpu->exception_index = EXCP_HLT; + cpu_loop_exit(current_cpu); +} + /* ITC Control View */ static inline uint64_t view_control_read(ITCStorageCell *c) @@ -182,6 +202,87 @@ static inline void view_control_write(ITCStorageCell *c, uint64_t val) } } +/* ITC Empty/Full View */ + +static uint64_t view_ef_common_read(ITCStorageCell *c, bool blocking) +{ + uint64_t ret = 0; + + if (!c->tag.FIFO) { + return 0; + } + + c->tag.F = 0; + + if (blocking && c->tag.E) { + block_thread_and_exit(c); + } + + if (c->blocked_threads) { + wake_blocked_threads(c); + } + + if (c->tag.FIFOPtr > 0) { + ret = c->data[c->fifo_out]; + c->fifo_out = (c->fifo_out + 1) % ITC_CELL_DEPTH; + c->tag.FIFOPtr--; + } + + if (c->tag.FIFOPtr == 0) { + c->tag.E = 1; + } + + return ret; +} + +static uint64_t view_ef_sync_read(ITCStorageCell *c) +{ + return view_ef_common_read(c, true); +} + +static uint64_t view_ef_try_read(ITCStorageCell *c) +{ + return view_ef_common_read(c, false); +} + +static inline void view_ef_common_write(ITCStorageCell *c, uint64_t val, + bool blocking) +{ + if (!c->tag.FIFO) { + return; + } + + c->tag.E = 0; + + if (blocking && c->tag.F) { + block_thread_and_exit(c); + } + + if (c->blocked_threads) { + wake_blocked_threads(c); + } + + if (c->tag.FIFOPtr < ITC_CELL_DEPTH) { + int idx = (c->fifo_out + c->tag.FIFOPtr) % ITC_CELL_DEPTH; + c->data[idx] = val; + c->tag.FIFOPtr++; + } + + if (c->tag.FIFOPtr == ITC_CELL_DEPTH) { + c->tag.F = 1; + } +} + +static void view_ef_sync_write(ITCStorageCell *c, uint64_t val) +{ + view_ef_common_write(c, val, true); +} + +static void view_ef_try_write(ITCStorageCell *c, uint64_t val) +{ + view_ef_common_write(c, val, false); +} + static uint64_t itc_storage_read(void *opaque, hwaddr addr, unsigned size) { MIPSITUState *s = (MIPSITUState *)opaque; @@ -193,6 +294,12 @@ static uint64_t itc_storage_read(void *opaque, hwaddr addr, unsigned size) case ITCVIEW_CONTROL: ret = view_control_read(cell); break; + case ITCVIEW_EF_SYNC: + ret = view_ef_sync_read(cell); + break; + case ITCVIEW_EF_TRY: + ret = view_ef_try_read(cell); + break; default: qemu_log_mask(LOG_GUEST_ERROR, "itc_storage_read: Bad ITC View %d\n", (int)view); @@ -213,6 +320,12 @@ static void itc_storage_write(void *opaque, hwaddr addr, uint64_t data, case ITCVIEW_CONTROL: view_control_write(cell, data); break; + case ITCVIEW_EF_SYNC: + view_ef_sync_write(cell, data); + break; + case ITCVIEW_EF_TRY: + view_ef_try_write(cell, data); + break; default: qemu_log_mask(LOG_GUEST_ERROR, "itc_storage_write: Bad ITC View %d\n", (int)view);