| From b6acbded6348817f213c18db66d7cb4be9432925 Mon Sep 17 00:00:00 2001 |
| From: Fugang Duan <fugang.duan@nxp.com> |
| Date: Tue, 11 Feb 2020 14:16:01 +0800 |
| Subject: [PATCH] tty: serial: imx: setup the correct sg entry for tx dma |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| commit f76707831829530ffdd3888bebc108aecefccaa0 upstream. |
| |
| There has oops as below happen on i.MX8MP EVK platform that has |
| 6G bytes DDR memory. |
| |
| when (xmit->tail < xmit->head) && (xmit->head == 0), |
| it setups one sg entry with sg->length is zero: |
| sg_set_buf(sgl + 1, xmit->buf, xmit->head); |
| |
| if xmit->buf is allocated from >4G address space, and SDMA only |
| support <4G address space, then dma_map_sg() will call swiotlb_map() |
| to do bounce buffer copying and mapping. |
| |
| But swiotlb_map() don't allow sg entry's length is zero, otherwise |
| report BUG_ON(). |
| |
| So the patch is to correct the tx DMA scatter list. |
| |
| Oops: |
| [ 287.675715] kernel BUG at kernel/dma/swiotlb.c:497! |
| [ 287.680592] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP |
| [ 287.686075] Modules linked in: |
| [ 287.689133] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.3-00016-g3fdc4e0-dirty #10 |
| [ 287.696872] Hardware name: FSL i.MX8MP EVK (DT) |
| [ 287.701402] pstate: 80000085 (Nzcv daIf -PAN -UAO) |
| [ 287.706199] pc : swiotlb_tbl_map_single+0x1fc/0x310 |
| [ 287.711076] lr : swiotlb_map+0x60/0x148 |
| [ 287.714909] sp : ffff800010003c00 |
| [ 287.718221] x29: ffff800010003c00 x28: 0000000000000000 |
| [ 287.723533] x27: 0000000000000040 x26: ffff800011ae0000 |
| [ 287.728844] x25: ffff800011ae09f8 x24: 0000000000000000 |
| [ 287.734155] x23: 00000001b7af9000 x22: 0000000000000000 |
| [ 287.739465] x21: ffff000176409c10 x20: 00000000001f7ffe |
| [ 287.744776] x19: ffff000176409c10 x18: 000000000000002e |
| [ 287.750087] x17: 0000000000000000 x16: 0000000000000000 |
| [ 287.755397] x15: 0000000000000000 x14: 0000000000000000 |
| [ 287.760707] x13: ffff00017f334000 x12: 0000000000000001 |
| [ 287.766018] x11: 00000000001fffff x10: 0000000000000000 |
| [ 287.771328] x9 : 0000000000000003 x8 : 0000000000000000 |
| [ 287.776638] x7 : 0000000000000000 x6 : 0000000000000000 |
| [ 287.781949] x5 : 0000000000200000 x4 : 0000000000000000 |
| [ 287.787259] x3 : 0000000000000001 x2 : 00000001b7af9000 |
| [ 287.792570] x1 : 00000000fbfff000 x0 : 0000000000000000 |
| [ 287.797881] Call trace: |
| [ 287.800328] swiotlb_tbl_map_single+0x1fc/0x310 |
| [ 287.804859] swiotlb_map+0x60/0x148 |
| [ 287.808347] dma_direct_map_page+0xf0/0x130 |
| [ 287.812530] dma_direct_map_sg+0x78/0xe0 |
| [ 287.816453] imx_uart_dma_tx+0x134/0x2f8 |
| [ 287.820374] imx_uart_dma_tx_callback+0xd8/0x168 |
| [ 287.824992] vchan_complete+0x194/0x200 |
| [ 287.828828] tasklet_action_common.isra.0+0x154/0x1a0 |
| [ 287.833879] tasklet_action+0x24/0x30 |
| [ 287.837540] __do_softirq+0x120/0x23c |
| [ 287.841202] irq_exit+0xb8/0xd8 |
| [ 287.844343] __handle_domain_irq+0x64/0xb8 |
| [ 287.848438] gic_handle_irq+0x5c/0x148 |
| [ 287.852185] el1_irq+0xb8/0x180 |
| [ 287.855327] cpuidle_enter_state+0x84/0x360 |
| [ 287.859508] cpuidle_enter+0x34/0x48 |
| [ 287.863083] call_cpuidle+0x18/0x38 |
| [ 287.866571] do_idle+0x1e0/0x280 |
| [ 287.869798] cpu_startup_entry+0x20/0x40 |
| [ 287.873721] rest_init+0xd4/0xe0 |
| [ 287.876949] arch_call_rest_init+0xc/0x14 |
| [ 287.880958] start_kernel+0x420/0x44c |
| [ 287.884622] Code: 9124c021 9417aff8 a94363f7 17ffffd5 (d4210000) |
| [ 287.890718] ---[ end trace 5bc44c4ab6b009ce ]--- |
| [ 287.895334] Kernel panic - not syncing: Fatal exception in interrupt |
| [ 287.901686] SMP: stopping secondary CPUs |
| [ 288.905607] SMP: failed to stop secondary CPUs 0-1 |
| [ 288.910395] Kernel Offset: disabled |
| [ 288.913882] CPU features: 0x0002,2000200c |
| [ 288.917888] Memory Limit: none |
| [ 288.920944] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- |
| |
| Reported-by: Eagle Zhou <eagle.zhou@nxp.com> |
| Tested-by: Eagle Zhou <eagle.zhou@nxp.com> |
| Signed-off-by: Fugang Duan <fugang.duan@nxp.com> |
| Cc: stable <stable@vger.kernel.org> |
| Fixes: 7942f8577f2a ("serial: imx: TX DMA: clean up sg initialization") |
| Reviewed-by: Uwe Kleine-Kรถnig <u.kleine-koenig@pengutronix.de> |
| Link: https://lore.kernel.org/r/1581401761-6378-1-git-send-email-fugang.duan@nxp.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c |
| index 8557a40abd95..97dc1cfe68ad 100644 |
| --- a/drivers/tty/serial/imx.c |
| +++ b/drivers/tty/serial/imx.c |
| @@ -609,7 +609,7 @@ static void imx_uart_dma_tx(struct imx_port *sport) |
| |
| sport->tx_bytes = uart_circ_chars_pending(xmit); |
| |
| - if (xmit->tail < xmit->head) { |
| + if (xmit->tail < xmit->head || xmit->head == 0) { |
| sport->dma_tx_nents = 1; |
| sg_init_one(sgl, xmit->buf + xmit->tail, sport->tx_bytes); |
| } else { |
| -- |
| 2.7.4 |
| |
