On 09/06/16 19:48, Ran Shalit wrote: > I have found a very good working example by Kevin Hilman in > https://github.com/khilman/omap-test-dmatest/blob/master/main.c yeah, this is doing memcpy. > I have made simple modifications for it to have 16-bit word > (OMAP_DMA_DATA_TYPE_S16 instead OMAP_DMA_DATA_TYPE_S32, using > buf_size/2 instead of buf_size/4, etc), which still works fine, when > doing memory-to-memory. > > Now, I try to work with the device memory by using ioremap_nocache() > instead of dma_alloc_coherent() as following: > > #if 1 > dma_test[i].dest_buf = > ioremap_nocache((0x00800000+0x00012000)*2, buf_size); What does the '*2' tries to achieve here? And why '(0x00800000+0x00012000)' and not '0x00812000' ? I assume that this is the base address of the area you want to write to, is it valid to write buf_size bytes after this base address? What you have set for dest_buf_phys? The DMA needs physical address. Have you changed the buf_size to fit your needs? > #else > dma_test[i].dest_buf = (unsigned long) > dma_alloc_coherent(NULL, buf_size, > (dma_addr_t *)&dma_test[i].dest_buf_phys, > GFP_KERNEL | GFP_DMA); > #endif > > But now I get exception in kernel: > [ 18.231536] ------------[ cut here ]------------ > [ 18.231567] WARNING: at arch/arm/mach-omap2/omap_l3_noc.c:117 > l3_interrupt_handler+0x144/0x190() > [ 18.231567] L3 custom error: MASTER:SDMA_Wr TARGET:GPMC > [ 18.231567] Modules linked in: dma(O) fpga(O) btwilink bluetooth > wl12xx wlcore mac80211 cfg80211 omapdrm_pvr(O) asix at24 wlcore_sdio > [ 18.231628] [<c001cbe4>] (unwind_backtrace+0x0/0xfc) from > [<c05c0af0>] (dump_stack+0x20/0x24) > [ 18.231658] [<c05c0af0>] (dump_stack+0x20/0x24) from [<c00465a4>] > (warn_slowpath_common+0x5c/0x74) > [ 18.231689] [<c00465a4>] (warn_slowpath_common+0x5c/0x74) from > [<c0046678>] (warn_slowpath_fmt+0x40/0x48) > [ 18.231689] [<c0046678>] (warn_slowpath_fmt+0x40/0x48) from > [<c003ab2c>] (l3_interrupt_handler+0x144/0x190) > [ 18.231719] [<c003ab2c>] (l3_interrupt_handler+0x144/0x190) from > [<c00c023c>] (handle_irq_event_percpu+0xb8/0x28c) > [ 18.231750] [<c00c023c>] (handle_irq_event_percpu+0xb8/0x28c) from > [<c00c045c>] (handle_irq_event+0x4c/0x6c) > [ 18.231750] [<c00c045c>] (handle_irq_event+0x4c/0x6c) from > [<c00c32dc>] (handle_fasteoi_irq+0xd8/0x144) > [ 18.231781] [<c00c32dc>] (handle_fasteoi_irq+0xd8/0x144) from > [<c00bfc28>] (generic_handle_irq+0x3c/0x50) > [ 18.231781] [<c00bfc28>] (generic_handle_irq+0x3c/0x50) from > [<c0015090>] (handle_IRQ+0x88/0xc8) > [ 18.231811] [<c0015090>] (handle_IRQ+0x88/0xc8) from [<c00086d4>] > (gic_handle_irq+0x54/0x74) > [ 18.231842] [<c00086d4>] (gic_handle_irq+0x54/0x74) from > [<c05c4a00>] (__irq_svc+0x40/0x70) > [ 18.231842] Exception stack(0xeb6a9e88 to 0xeb6a9ed0) > [ 18.231842] 9e80: c093836c 60070113 00000000 > 00000000 c093836c 60070113 > [ 18.231872] 9ea0: 00000000 00000001 00000003 00000002 0000001c > eb6a9edc eb6a9ee0 eb6a9ed0 > [ 18.231872] 9ec0: c0074d7c c05c40b8 60070113 ffffffff > [ 18.231903] [<c05c4a00>] (__irq_svc+0x40/0x70) from [<c05c40b8>] > (_raw_spin_unlock_irqrestore+0x2c/0x54) > [ 18.231903] [<c05c40b8>] (_raw_spin_unlock_irqrestore+0x2c/0x54) > from [<c0074d7c>] (__wake_up+0x54/0x5c) > [ 18.231933] [<c0074d7c>] (__wake_up+0x54/0x5c) from [<c009d6b0>] > (sys_init_module+0x10cc/0x1174) > [ 18.231964] [<c009d6b0>] (sys_init_module+0x10cc/0x1174) from > [<c0013f00>] (ret_fast_syscall+0x0/0x30) > [ 18.231964] ---[ end trace da227214a82491bb ]--- > [ 18.231994] DMA transaction error with device 0 > [ 18.231994] dma_callback(): lch=0x0, ch_status=0x0100, count=1/0 > [ 23.350738] DMA copy failed at offset 0x0. Expected 0x00000000, > got 0x00005678 > > Isn't it legal to work with the io mapped memory as done above ? -- Péter -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
