3  * 8250_dma.c - DMA Engine API support for 8250.c
10 #include <linux/dma-mapping.h>
17 	struct uart_8250_dma	*dma = p->dma;  in __dma_tx_complete()  local
22 	dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,  in __dma_tx_complete()
27 	dma->tx_running = 0;  in __dma_tx_complete()
29 	uart_xmit_advance(&p->port, dma->tx_size);  in __dma_tx_complete()
35 	if (ret || !dma->tx_running)  in __dma_tx_complete()
43 	struct uart_8250_dma	*dma = p->dma;  in __dma_rx_complete()  local
50 	 * New DMA Rx can be started during the completion handler before it  in __dma_rx_complete()
54 	dma_status = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);  in __dma_rx_complete()
58 	count = dma->rx_size - state.residue;  in __dma_rx_complete()
60 	tty_insert_flip_string(tty_port, dma->rx_buf, count);  in __dma_rx_complete()
62 	dma->rx_running = 0;  in __dma_rx_complete()
70 	struct uart_8250_dma *dma = p->dma;  in dma_rx_complete()  local
74 	if (dma->rx_running)  in dma_rx_complete()
79 	 * changes dma->rx_running.  in dma_rx_complete()
81 	if (!dma->rx_running && (serial_lsr_in(p) & UART_LSR_DR))  in dma_rx_complete()
82 		p->dma->rx_dma(p);  in dma_rx_complete()
88 	struct uart_8250_dma		*dma = p->dma;  in serial8250_tx_dma()  local
97 	if (dma->tx_running) {  in serial8250_tx_dma()
99 			dmaengine_pause(dma->txchan);  in serial8250_tx_dma()
101 			dmaengine_resume(dma->txchan);  in serial8250_tx_dma()
118 					   UART_XMIT_SIZE, dma->tx_addr);  in serial8250_tx_dma()
120 	dma->tx_size = 0;  in serial8250_tx_dma()
123 		dma->tx_size += sg_dma_len(sg);  in serial8250_tx_dma()
125 	desc = dmaengine_prep_slave_sg(dma->txchan, sgl, ret,  in serial8250_tx_dma()
133 	dma->tx_running = 1;  in serial8250_tx_dma()
137 	dma->tx_cookie = dmaengine_submit(desc);  in serial8250_tx_dma()
139 	dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,  in serial8250_tx_dma()
142 	dma_async_issue_pending(dma->txchan);  in serial8250_tx_dma()
144 	dma->tx_err = 0;  in serial8250_tx_dma()
148 	dma->tx_err = 1;  in serial8250_tx_dma()
154 	struct uart_8250_dma		*dma = p->dma;  in serial8250_rx_dma()  local
157 	if (dma->rx_running)  in serial8250_rx_dma()
162 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,  in serial8250_rx_dma()
163 					   dma->rx_size, DMA_DEV_TO_MEM,  in serial8250_rx_dma()
168 	dma->rx_running = 1;  in serial8250_rx_dma()
172 	dma->rx_cookie = dmaengine_submit(desc);  in serial8250_rx_dma()
174 	dma_async_issue_pending(dma->rxchan);  in serial8250_rx_dma()
181 	struct uart_8250_dma *dma = p->dma;  in serial8250_rx_dma_flush()  local
183 	if (dma->rx_running) {  in serial8250_rx_dma_flush()
184 		dmaengine_pause(dma->rxchan);  in serial8250_rx_dma_flush()
186 		dmaengine_terminate_async(dma->rxchan);  in serial8250_rx_dma_flush()
193 	struct uart_8250_dma	*dma = p->dma;  in serial8250_request_dma()  local
194 	phys_addr_t rx_dma_addr = dma->rx_dma_addr ?  in serial8250_request_dma()
195 				  dma->rx_dma_addr : p->port.mapbase;  in serial8250_request_dma()
196 	phys_addr_t tx_dma_addr = dma->tx_dma_addr ?  in serial8250_request_dma()
197 				  dma->tx_dma_addr : p->port.mapbase;  in serial8250_request_dma()
203 	dma->rxconf.direction		= DMA_DEV_TO_MEM;  in serial8250_request_dma()
204 	dma->rxconf.src_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;  in serial8250_request_dma()
205 	dma->rxconf.src_addr		= rx_dma_addr + UART_RX;  in serial8250_request_dma()
207 	dma->txconf.direction		= DMA_MEM_TO_DEV;  in serial8250_request_dma()
208 	dma->txconf.dst_addr_width	= DMA_SLAVE_BUSWIDTH_1_BYTE;  in serial8250_request_dma()
209 	dma->txconf.dst_addr		= tx_dma_addr + UART_TX;  in serial8250_request_dma()
215 	dma->rxchan = dma_request_slave_channel_compat(mask,  in serial8250_request_dma()
216 						       dma->fn, dma->rx_param,  in serial8250_request_dma()
218 	if (!dma->rxchan)  in serial8250_request_dma()
221 	/* 8250 rx dma requires dmaengine driver to support pause/terminate */  in serial8250_request_dma()
222 	ret = dma_get_slave_caps(dma->rxchan, &caps);  in serial8250_request_dma()
231 	dmaengine_slave_config(dma->rxchan, &dma->rxconf);  in serial8250_request_dma()
234 	dma->txchan = dma_request_slave_channel_compat(mask,  in serial8250_request_dma()
235 						       dma->fn, dma->tx_param,  in serial8250_request_dma()
237 	if (!dma->txchan) {  in serial8250_request_dma()
242 	/* 8250 tx dma requires dmaengine driver to support terminate */  in serial8250_request_dma()
243 	ret = dma_get_slave_caps(dma->txchan, &caps);  in serial8250_request_dma()
251 	dmaengine_slave_config(dma->txchan, &dma->txconf);  in serial8250_request_dma()
254 	if (!dma->rx_size)  in serial8250_request_dma()
255 		dma->rx_size = PAGE_SIZE;  in serial8250_request_dma()
257 	dma->rx_buf = dma_alloc_coherent(dma->rxchan->device->dev, dma->rx_size,  in serial8250_request_dma()
258 					&dma->rx_addr, GFP_KERNEL);  in serial8250_request_dma()
259 	if (!dma->rx_buf) {  in serial8250_request_dma()
265 	dma->tx_addr = dma_map_single(dma->txchan->device->dev,  in serial8250_request_dma()
269 	if (dma_mapping_error(dma->txchan->device->dev, dma->tx_addr)) {  in serial8250_request_dma()
270 		dma_free_coherent(dma->rxchan->device->dev, dma->rx_size,  in serial8250_request_dma()
271 				  dma->rx_buf, dma->rx_addr);  in serial8250_request_dma()
276 	dev_dbg_ratelimited(p->port.dev, "got both dma channels\n");  in serial8250_request_dma()
280 	dma_release_channel(dma->txchan);  in serial8250_request_dma()
282 	dma_release_channel(dma->rxchan);  in serial8250_request_dma()
289 	struct uart_8250_dma *dma = p->dma;  in serial8250_release_dma()  local
291 	if (!dma)  in serial8250_release_dma()
295 	dmaengine_terminate_sync(dma->rxchan);  in serial8250_release_dma()
296 	dma_free_coherent(dma->rxchan->device->dev, dma->rx_size, dma->rx_buf,  in serial8250_release_dma()
297 			  dma->rx_addr);  in serial8250_release_dma()
298 	dma_release_channel(dma->rxchan);  in serial8250_release_dma()
299 	dma->rxchan = NULL;  in serial8250_release_dma()
302 	dmaengine_terminate_sync(dma->txchan);  in serial8250_release_dma()
303 	dma_unmap_single(dma->txchan->device->dev, dma->tx_addr,  in serial8250_release_dma()
305 	dma_release_channel(dma->txchan);  in serial8250_release_dma()
306 	dma->txchan = NULL;  in serial8250_release_dma()
307 	dma->tx_running = 0;  in serial8250_release_dma()
309 	dev_dbg_ratelimited(p->port.dev, "dma channels released\n");  in serial8250_release_dma()