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[147.11.176.192]) by smtp.gmail.com with ESMTPSA id qe17sm14660222pjb.39.2021.09.26.19.21.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Sep 2021 19:21:23 -0700 (PDT) From: Bin Meng To: Alistair Francis , qemu-devel@nongnu.org, qemu-riscv@nongnu.org Cc: Frank Chang Subject: [PATCH 2/2] hw/dma: sifive_pdma: Don't run DMA when channel is disclaimed Date: Mon, 27 Sep 2021 10:21:13 +0800 Message-Id: <20210927022113.1518559-2-bmeng.cn@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210927022113.1518559-1-bmeng.cn@gmail.com> References: <20210927022113.1518559-1-bmeng.cn@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::102a; envelope-from=bmeng.cn@gmail.com; helo=mail-pj1-x102a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-riscv@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Sep 2021 02:21:28 -0000 If Control.run bit is set while not preserving the Control.claim bit, the DMA transfer shall not be started. The following result is PDMA tested in U-Boot on Unleashed board: => mw.l 0x3000000 0x0 <= Disclaim channel 0 => mw.l 0x3000000 0x1 <= Claim channel 0 => mw.l 0x3000004 0x55000000 <= wsize = rsize = 5 (2^5 = 32 bytes) => mw.q 0x3000008 0x2 <= NextBytes = 2 => mw.q 0x3000010 0x84000000 <= NextDestination = 0x84000000 => mw.q 0x3000018 0x84001000 <= NextSource = 0x84001000 => mw.l 0x84000000 0x87654321 <= Fill test data to dst => mw.l 0x84001000 0x12345678 <= Fill test data to src => md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents 84000000: 87654321 !Ce. 84001000: 12345678 xV4. => md.l 0x3000000 8 <= Dump PDMA status 03000000: 00000001 55000000 00000002 00000000 .......U........ 03000010: 84000000 00000000 84001000 00000000 ................ => mw.l 0x3000000 0x2 <= Set channel 0 run bit only => md.l 0x3000000 8 <= Dump PDMA status 03000000: 00000000 55000000 00000002 00000000 .......U........ 03000010: 84000000 00000000 84001000 00000000 ................ => md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents 84000000: 87654321 !Ce. 84001000: 12345678 xV4. Signed-off-by: Bin Meng --- hw/dma/sifive_pdma.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/hw/dma/sifive_pdma.c b/hw/dma/sifive_pdma.c index b8ec7621f3..85fe34f5f3 100644 --- a/hw/dma/sifive_pdma.c +++ b/hw/dma/sifive_pdma.c @@ -232,7 +232,7 @@ static void sifive_pdma_write(void *opaque, hwaddr offset, { SiFivePDMAState *s = opaque; int ch = SIFIVE_PDMA_CHAN_NO(offset); - bool claimed; + bool claimed, run; if (ch >= SIFIVE_PDMA_CHANS) { qemu_log_mask(LOG_GUEST_ERROR, "%s: Invalid channel no %d\n", @@ -244,6 +244,7 @@ static void sifive_pdma_write(void *opaque, hwaddr offset, switch (offset) { case DMA_CONTROL: claimed = !!(s->chan[ch].control & CONTROL_CLAIM); + run = !!(s->chan[ch].control & CONTROL_RUN); if (!claimed && (value & CONTROL_CLAIM)) { /* reset Next* registers */ @@ -254,13 +255,19 @@ static void sifive_pdma_write(void *opaque, hwaddr offset, s->chan[ch].next_src = 0; } + /* claim bit can only be cleared when run is low */ + if (run && !(value & CONTROL_CLAIM)) { + value |= CONTROL_CLAIM; + } + s->chan[ch].control = value; /* * If channel was not claimed before run bit is set, + * or if the channel is disclaimed when run was low, * DMA won't run. */ - if (!claimed) { + if (!claimed || (!run && !(value & CONTROL_CLAIM))) { s->chan[ch].control &= ~CONTROL_RUN; return; } -- 2.25.1