1
2
3
4
5
6
7
8
9
10
11
12
13#include <linux/module.h>
14#include <linux/types.h>
15#include <linux/tty.h>
16#include <linux/errno.h>
17#include <linux/device.h>
18#include <linux/io.h>
19#include <linux/of.h>
20#include <linux/dma-mapping.h>
21#include <linux/tty_flip.h>
22#include <linux/delay.h>
23#include <linux/clk.h>
24#include <linux/debugfs.h>
25
26#include "8250.h"
27
28
29#define UDMA_ARB_RX 0x00
30#define UDMA_ARB_TX 0x04
31#define UDMA_ARB_REQ 0x00000001
32#define UDMA_ARB_GRANT 0x00000002
33
34#define UDMA_RX_REVISION 0x00
35#define UDMA_RX_REVISION_REQUIRED 0x00000101
36#define UDMA_RX_CTRL 0x04
37#define UDMA_RX_CTRL_BUF_CLOSE_MODE 0x00010000
38#define UDMA_RX_CTRL_MASK_WR_DONE 0x00008000
39#define UDMA_RX_CTRL_ENDIAN_OVERRIDE 0x00004000
40#define UDMA_RX_CTRL_ENDIAN 0x00002000
41#define UDMA_RX_CTRL_OE_IS_ERR 0x00001000
42#define UDMA_RX_CTRL_PE_IS_ERR 0x00000800
43#define UDMA_RX_CTRL_FE_IS_ERR 0x00000400
44#define UDMA_RX_CTRL_NUM_BUF_USED_MASK 0x000003c0
45#define UDMA_RX_CTRL_NUM_BUF_USED_SHIFT 6
46#define UDMA_RX_CTRL_BUF_CLOSE_CLK_SEL_SYS 0x00000020
47#define UDMA_RX_CTRL_BUF_CLOSE_ENA 0x00000010
48#define UDMA_RX_CTRL_TIMEOUT_CLK_SEL_SYS 0x00000008
49#define UDMA_RX_CTRL_TIMEOUT_ENA 0x00000004
50#define UDMA_RX_CTRL_ABORT 0x00000002
51#define UDMA_RX_CTRL_ENA 0x00000001
52#define UDMA_RX_STATUS 0x08
53#define UDMA_RX_STATUS_ACTIVE_BUF_MASK 0x0000000f
54#define UDMA_RX_TRANSFER_LEN 0x0c
55#define UDMA_RX_TRANSFER_TOTAL 0x10
56#define UDMA_RX_BUFFER_SIZE 0x14
57#define UDMA_RX_SRC_ADDR 0x18
58#define UDMA_RX_TIMEOUT 0x1c
59#define UDMA_RX_BUFFER_CLOSE 0x20
60#define UDMA_RX_BLOCKOUT_COUNTER 0x24
61#define UDMA_RX_BUF0_PTR_LO 0x28
62#define UDMA_RX_BUF0_PTR_HI 0x2c
63#define UDMA_RX_BUF0_STATUS 0x30
64#define UDMA_RX_BUFX_STATUS_OVERRUN_ERR 0x00000010
65#define UDMA_RX_BUFX_STATUS_FRAME_ERR 0x00000008
66#define UDMA_RX_BUFX_STATUS_PARITY_ERR 0x00000004
67#define UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED 0x00000002
68#define UDMA_RX_BUFX_STATUS_DATA_RDY 0x00000001
69#define UDMA_RX_BUF0_DATA_LEN 0x34
70#define UDMA_RX_BUF1_PTR_LO 0x38
71#define UDMA_RX_BUF1_PTR_HI 0x3c
72#define UDMA_RX_BUF1_STATUS 0x40
73#define UDMA_RX_BUF1_DATA_LEN 0x44
74
75#define UDMA_TX_REVISION 0x00
76#define UDMA_TX_REVISION_REQUIRED 0x00000101
77#define UDMA_TX_CTRL 0x04
78#define UDMA_TX_CTRL_ENDIAN_OVERRIDE 0x00000080
79#define UDMA_TX_CTRL_ENDIAN 0x00000040
80#define UDMA_TX_CTRL_NUM_BUF_USED_MASK 0x00000030
81#define UDMA_TX_CTRL_NUM_BUF_USED_1 0x00000010
82#define UDMA_TX_CTRL_ABORT 0x00000002
83#define UDMA_TX_CTRL_ENA 0x00000001
84#define UDMA_TX_DST_ADDR 0x08
85#define UDMA_TX_BLOCKOUT_COUNTER 0x10
86#define UDMA_TX_TRANSFER_LEN 0x14
87#define UDMA_TX_TRANSFER_TOTAL 0x18
88#define UDMA_TX_STATUS 0x20
89#define UDMA_TX_BUF0_PTR_LO 0x24
90#define UDMA_TX_BUF0_PTR_HI 0x28
91#define UDMA_TX_BUF0_STATUS 0x2c
92#define UDMA_TX_BUFX_LAST 0x00000002
93#define UDMA_TX_BUFX_EMPTY 0x00000001
94#define UDMA_TX_BUF0_DATA_LEN 0x30
95#define UDMA_TX_BUF0_DATA_SENT 0x34
96#define UDMA_TX_BUF1_PTR_LO 0x38
97
98#define UDMA_INTR_STATUS 0x00
99#define UDMA_INTR_ARB_TX_GRANT 0x00040000
100#define UDMA_INTR_ARB_RX_GRANT 0x00020000
101#define UDMA_INTR_TX_ALL_EMPTY 0x00010000
102#define UDMA_INTR_TX_EMPTY_BUF1 0x00008000
103#define UDMA_INTR_TX_EMPTY_BUF0 0x00004000
104#define UDMA_INTR_TX_ABORT 0x00002000
105#define UDMA_INTR_TX_DONE 0x00001000
106#define UDMA_INTR_RX_ERROR 0x00000800
107#define UDMA_INTR_RX_TIMEOUT 0x00000400
108#define UDMA_INTR_RX_READY_BUF7 0x00000200
109#define UDMA_INTR_RX_READY_BUF6 0x00000100
110#define UDMA_INTR_RX_READY_BUF5 0x00000080
111#define UDMA_INTR_RX_READY_BUF4 0x00000040
112#define UDMA_INTR_RX_READY_BUF3 0x00000020
113#define UDMA_INTR_RX_READY_BUF2 0x00000010
114#define UDMA_INTR_RX_READY_BUF1 0x00000008
115#define UDMA_INTR_RX_READY_BUF0 0x00000004
116#define UDMA_INTR_RX_READY_MASK 0x000003fc
117#define UDMA_INTR_RX_READY_SHIFT 2
118#define UDMA_INTR_RX_ABORT 0x00000002
119#define UDMA_INTR_RX_DONE 0x00000001
120#define UDMA_INTR_SET 0x04
121#define UDMA_INTR_CLEAR 0x08
122#define UDMA_INTR_MASK_STATUS 0x0c
123#define UDMA_INTR_MASK_SET 0x10
124#define UDMA_INTR_MASK_CLEAR 0x14
125
126
127#define UDMA_RX_INTERRUPTS ( \
128 UDMA_INTR_RX_ERROR | \
129 UDMA_INTR_RX_TIMEOUT | \
130 UDMA_INTR_RX_READY_BUF0 | \
131 UDMA_INTR_RX_READY_BUF1 | \
132 UDMA_INTR_RX_READY_BUF2 | \
133 UDMA_INTR_RX_READY_BUF3 | \
134 UDMA_INTR_RX_READY_BUF4 | \
135 UDMA_INTR_RX_READY_BUF5 | \
136 UDMA_INTR_RX_READY_BUF6 | \
137 UDMA_INTR_RX_READY_BUF7 | \
138 UDMA_INTR_RX_ABORT | \
139 UDMA_INTR_RX_DONE)
140
141#define UDMA_RX_ERR_INTERRUPTS ( \
142 UDMA_INTR_RX_ERROR | \
143 UDMA_INTR_RX_TIMEOUT | \
144 UDMA_INTR_RX_ABORT | \
145 UDMA_INTR_RX_DONE)
146
147#define UDMA_TX_INTERRUPTS ( \
148 UDMA_INTR_TX_ABORT | \
149 UDMA_INTR_TX_DONE)
150
151#define UDMA_IS_RX_INTERRUPT(status) ((status) & UDMA_RX_INTERRUPTS)
152#define UDMA_IS_TX_INTERRUPT(status) ((status) & UDMA_TX_INTERRUPTS)
153
154
155
156#define UDMA_RX_BUFS_COUNT 8
157#define UDMA_RX_BUFS_REG_OFFSET (UDMA_RX_BUF1_PTR_LO - UDMA_RX_BUF0_PTR_LO)
158#define UDMA_RX_BUFx_PTR_LO(x) (UDMA_RX_BUF0_PTR_LO + \
159 ((x) * UDMA_RX_BUFS_REG_OFFSET))
160#define UDMA_RX_BUFx_PTR_HI(x) (UDMA_RX_BUF0_PTR_HI + \
161 ((x) * UDMA_RX_BUFS_REG_OFFSET))
162#define UDMA_RX_BUFx_STATUS(x) (UDMA_RX_BUF0_STATUS + \
163 ((x) * UDMA_RX_BUFS_REG_OFFSET))
164#define UDMA_RX_BUFx_DATA_LEN(x) (UDMA_RX_BUF0_DATA_LEN + \
165 ((x) * UDMA_RX_BUFS_REG_OFFSET))
166
167
168#define UDMA_TX_BUFS_COUNT 2
169#define UDMA_TX_BUFS_REG_OFFSET (UDMA_TX_BUF1_PTR_LO - UDMA_TX_BUF0_PTR_LO)
170#define UDMA_TX_BUFx_PTR_LO(x) (UDMA_TX_BUF0_PTR_LO + \
171 ((x) * UDMA_TX_BUFS_REG_OFFSET))
172#define UDMA_TX_BUFx_PTR_HI(x) (UDMA_TX_BUF0_PTR_HI + \
173 ((x) * UDMA_TX_BUFS_REG_OFFSET))
174#define UDMA_TX_BUFx_STATUS(x) (UDMA_TX_BUF0_STATUS + \
175 ((x) * UDMA_TX_BUFS_REG_OFFSET))
176#define UDMA_TX_BUFx_DATA_LEN(x) (UDMA_TX_BUF0_DATA_LEN + \
177 ((x) * UDMA_TX_BUFS_REG_OFFSET))
178#define UDMA_TX_BUFx_DATA_SENT(x) (UDMA_TX_BUF0_DATA_SENT + \
179 ((x) * UDMA_TX_BUFS_REG_OFFSET))
180#define REGS_8250 0
181#define REGS_DMA_RX 1
182#define REGS_DMA_TX 2
183#define REGS_DMA_ISR 3
184#define REGS_DMA_ARB 4
185#define REGS_MAX 5
186
187#define TX_BUF_SIZE 4096
188#define RX_BUF_SIZE 4096
189#define RX_BUFS_COUNT 2
190#define KHZ 1000
191#define MHZ(x) ((x) * KHZ * KHZ)
192
193static const u32 brcmstb_rate_table[] = {
194 MHZ(81),
195 MHZ(108),
196 MHZ(64),
197 MHZ(48),
198};
199
200static const u32 brcmstb_rate_table_7278[] = {
201 MHZ(81),
202 MHZ(108),
203 0,
204 MHZ(48),
205};
206
207struct brcmuart_priv {
208 int line;
209 struct clk *baud_mux_clk;
210 unsigned long default_mux_rate;
211 u32 real_rates[ARRAY_SIZE(brcmstb_rate_table)];
212 const u32 *rate_table;
213 ktime_t char_wait;
214 struct uart_port *up;
215 struct hrtimer hrt;
216 bool shutdown;
217 bool dma_enabled;
218 struct uart_8250_dma dma;
219 void __iomem *regs[REGS_MAX];
220 dma_addr_t rx_addr;
221 void *rx_bufs;
222 size_t rx_size;
223 int rx_next_buf;
224 dma_addr_t tx_addr;
225 void *tx_buf;
226 size_t tx_size;
227 bool tx_running;
228 bool rx_running;
229 struct dentry *debugfs_dir;
230
231
232 u64 dma_rx_partial_buf;
233 u64 dma_rx_full_buf;
234 u32 rx_bad_timeout_late_char;
235 u32 rx_bad_timeout_no_char;
236 u32 rx_missing_close_timeout;
237 u32 rx_err;
238 u32 rx_timeout;
239 u32 rx_abort;
240};
241
242static struct dentry *brcmuart_debugfs_root;
243
244
245
246
247static u32 udma_readl(struct brcmuart_priv *priv,
248 int reg_type, int offset)
249{
250 return readl(priv->regs[reg_type] + offset);
251}
252
253static void udma_writel(struct brcmuart_priv *priv,
254 int reg_type, int offset, u32 value)
255{
256 writel(value, priv->regs[reg_type] + offset);
257}
258
259static void udma_set(struct brcmuart_priv *priv,
260 int reg_type, int offset, u32 bits)
261{
262 void __iomem *reg = priv->regs[reg_type] + offset;
263 u32 value;
264
265 value = readl(reg);
266 value |= bits;
267 writel(value, reg);
268}
269
270static void udma_unset(struct brcmuart_priv *priv,
271 int reg_type, int offset, u32 bits)
272{
273 void __iomem *reg = priv->regs[reg_type] + offset;
274 u32 value;
275
276 value = readl(reg);
277 value &= ~bits;
278 writel(value, reg);
279}
280
281
282
283
284
285
286
287static int brcmuart_arbitration(struct brcmuart_priv *priv, bool acquire)
288{
289 u32 rx_grant;
290 u32 tx_grant;
291 int waits;
292 int ret = 0;
293
294 if (acquire) {
295 udma_set(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ);
296 udma_set(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ);
297
298 waits = 1;
299 while (1) {
300 rx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_RX);
301 tx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_TX);
302 if (rx_grant & tx_grant & UDMA_ARB_GRANT)
303 return 0;
304 if (waits-- == 0)
305 break;
306 msleep(1);
307 }
308 ret = 1;
309 }
310
311 udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ);
312 udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ);
313 return ret;
314}
315
316static void brcmuart_init_dma_hardware(struct brcmuart_priv *priv)
317{
318 u32 daddr;
319 u32 value;
320 int x;
321
322
323 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, 0xffffffff);
324
325 udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_SIZE, RX_BUF_SIZE);
326
327
328
329
330
331 udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_CLOSE, 16*10*32);
332 value = (RX_BUFS_COUNT << UDMA_RX_CTRL_NUM_BUF_USED_SHIFT)
333 | UDMA_RX_CTRL_BUF_CLOSE_MODE
334 | UDMA_RX_CTRL_BUF_CLOSE_ENA;
335 udma_writel(priv, REGS_DMA_RX, UDMA_RX_CTRL, value);
336
337 udma_writel(priv, REGS_DMA_RX, UDMA_RX_BLOCKOUT_COUNTER, 0);
338 daddr = priv->rx_addr;
339 for (x = 0; x < RX_BUFS_COUNT; x++) {
340
341
342 udma_writel(priv, REGS_DMA_RX, UDMA_RX_TRANSFER_LEN, 0);
343
344 udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_LO(x),
345 lower_32_bits(daddr));
346 udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_HI(x),
347 upper_32_bits(daddr));
348 daddr += RX_BUF_SIZE;
349 }
350
351 daddr = priv->tx_addr;
352 udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_LO(0),
353 lower_32_bits(daddr));
354 udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_HI(0),
355 upper_32_bits(daddr));
356 udma_writel(priv, REGS_DMA_TX, UDMA_TX_CTRL,
357 UDMA_TX_CTRL_NUM_BUF_USED_1);
358
359
360 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, 0xffffffff);
361 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR,
362 UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS);
363
364}
365
366static void start_rx_dma(struct uart_8250_port *p)
367{
368 struct brcmuart_priv *priv = p->port.private_data;
369 int x;
370
371 udma_unset(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA);
372
373
374 for (x = 0; x < RX_BUFS_COUNT; x++)
375 udma_unset(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(x),
376 UDMA_RX_BUFX_STATUS_DATA_RDY);
377
378
379 udma_unset(priv, REGS_DMA_RX, UDMA_RX_STATUS,
380 UDMA_RX_STATUS_ACTIVE_BUF_MASK);
381 priv->rx_next_buf = 0;
382
383 udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA);
384 priv->rx_running = true;
385}
386
387static void stop_rx_dma(struct uart_8250_port *p)
388{
389 struct brcmuart_priv *priv = p->port.private_data;
390
391
392 if (priv->rx_running)
393 udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ABORT);
394}
395
396static int stop_tx_dma(struct uart_8250_port *p)
397{
398 struct brcmuart_priv *priv = p->port.private_data;
399 u32 value;
400
401
402 value = udma_readl(priv, REGS_DMA_TX, UDMA_TX_CTRL);
403 if (value & UDMA_TX_CTRL_ENA)
404 udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ABORT);
405 priv->tx_running = false;
406 return 0;
407}
408
409
410
411
412
413static int brcmuart_tx_dma(struct uart_8250_port *p)
414{
415 struct brcmuart_priv *priv = p->port.private_data;
416 struct circ_buf *xmit = &p->port.state->xmit;
417 u32 tx_size;
418
419 if (uart_tx_stopped(&p->port) || priv->tx_running ||
420 uart_circ_empty(xmit)) {
421 return 0;
422 }
423 tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
424
425 priv->dma.tx_err = 0;
426 memcpy(priv->tx_buf, &xmit->buf[xmit->tail], tx_size);
427 xmit->tail += tx_size;
428 xmit->tail &= UART_XMIT_SIZE - 1;
429 p->port.icount.tx += tx_size;
430
431 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
432 uart_write_wakeup(&p->port);
433
434 udma_writel(priv, REGS_DMA_TX, UDMA_TX_TRANSFER_LEN, tx_size);
435 udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUF0_DATA_LEN, tx_size);
436 udma_unset(priv, REGS_DMA_TX, UDMA_TX_BUF0_STATUS, UDMA_TX_BUFX_EMPTY);
437 udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ENA);
438 priv->tx_running = true;
439
440 return 0;
441}
442
443static void brcmuart_rx_buf_done_isr(struct uart_port *up, int index)
444{
445 struct brcmuart_priv *priv = up->private_data;
446 struct tty_port *tty_port = &up->state->port;
447 u32 status;
448 u32 length;
449 u32 copied;
450
451
452 status = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(index));
453 length = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_DATA_LEN(index));
454
455 if ((status & UDMA_RX_BUFX_STATUS_DATA_RDY) == 0) {
456 dev_err(up->dev, "RX done interrupt but DATA_RDY not found\n");
457 return;
458 }
459 if (status & (UDMA_RX_BUFX_STATUS_OVERRUN_ERR |
460 UDMA_RX_BUFX_STATUS_FRAME_ERR |
461 UDMA_RX_BUFX_STATUS_PARITY_ERR)) {
462 if (status & UDMA_RX_BUFX_STATUS_OVERRUN_ERR) {
463 up->icount.overrun++;
464 dev_warn(up->dev, "RX OVERRUN Error\n");
465 }
466 if (status & UDMA_RX_BUFX_STATUS_FRAME_ERR) {
467 up->icount.frame++;
468 dev_warn(up->dev, "RX FRAMING Error\n");
469 }
470 if (status & UDMA_RX_BUFX_STATUS_PARITY_ERR) {
471 up->icount.parity++;
472 dev_warn(up->dev, "RX PARITY Error\n");
473 }
474 }
475 copied = (u32)tty_insert_flip_string(
476 tty_port,
477 priv->rx_bufs + (index * RX_BUF_SIZE),
478 length);
479 if (copied != length) {
480 dev_warn(up->dev, "Flip buffer overrun of %d bytes\n",
481 length - copied);
482 up->icount.overrun += length - copied;
483 }
484 up->icount.rx += length;
485 if (status & UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED)
486 priv->dma_rx_partial_buf++;
487 else if (length != RX_BUF_SIZE)
488
489
490
491
492 priv->rx_missing_close_timeout++;
493 else
494 priv->dma_rx_full_buf++;
495
496 tty_flip_buffer_push(tty_port);
497}
498
499static void brcmuart_rx_isr(struct uart_port *up, u32 rx_isr)
500{
501 struct brcmuart_priv *priv = up->private_data;
502 struct device *dev = up->dev;
503 u32 rx_done_isr;
504 u32 check_isr;
505
506 rx_done_isr = (rx_isr & UDMA_INTR_RX_READY_MASK);
507 while (rx_done_isr) {
508 check_isr = UDMA_INTR_RX_READY_BUF0 << priv->rx_next_buf;
509 if (check_isr & rx_done_isr) {
510 brcmuart_rx_buf_done_isr(up, priv->rx_next_buf);
511 } else {
512 dev_err(dev,
513 "RX buffer ready out of sequence, restarting RX DMA\n");
514 start_rx_dma(up_to_u8250p(up));
515 break;
516 }
517 if (rx_isr & UDMA_RX_ERR_INTERRUPTS) {
518 if (rx_isr & UDMA_INTR_RX_ERROR)
519 priv->rx_err++;
520 if (rx_isr & UDMA_INTR_RX_TIMEOUT) {
521 priv->rx_timeout++;
522 dev_err(dev, "RX TIMEOUT Error\n");
523 }
524 if (rx_isr & UDMA_INTR_RX_ABORT)
525 priv->rx_abort++;
526 priv->rx_running = false;
527 }
528
529 if (!(rx_isr & UDMA_INTR_RX_ABORT))
530 udma_unset(priv, REGS_DMA_RX,
531 UDMA_RX_BUFx_STATUS(priv->rx_next_buf),
532 UDMA_RX_BUFX_STATUS_DATA_RDY);
533 rx_done_isr &= ~check_isr;
534 priv->rx_next_buf++;
535 if (priv->rx_next_buf == RX_BUFS_COUNT)
536 priv->rx_next_buf = 0;
537 }
538}
539
540static void brcmuart_tx_isr(struct uart_port *up, u32 isr)
541{
542 struct brcmuart_priv *priv = up->private_data;
543 struct device *dev = up->dev;
544 struct uart_8250_port *port_8250 = up_to_u8250p(up);
545 struct circ_buf *xmit = &port_8250->port.state->xmit;
546
547 if (isr & UDMA_INTR_TX_ABORT) {
548 if (priv->tx_running)
549 dev_err(dev, "Unexpected TX_ABORT interrupt\n");
550 return;
551 }
552 priv->tx_running = false;
553 if (!uart_circ_empty(xmit) && !uart_tx_stopped(up))
554 brcmuart_tx_dma(port_8250);
555}
556
557static irqreturn_t brcmuart_isr(int irq, void *dev_id)
558{
559 struct uart_port *up = dev_id;
560 struct device *dev = up->dev;
561 struct brcmuart_priv *priv = up->private_data;
562 unsigned long flags;
563 u32 interrupts;
564 u32 rval;
565 u32 tval;
566
567 interrupts = udma_readl(priv, REGS_DMA_ISR, UDMA_INTR_STATUS);
568 if (interrupts == 0)
569 return IRQ_NONE;
570
571 spin_lock_irqsave(&up->lock, flags);
572
573
574 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, interrupts);
575
576 rval = UDMA_IS_RX_INTERRUPT(interrupts);
577 if (rval)
578 brcmuart_rx_isr(up, rval);
579 tval = UDMA_IS_TX_INTERRUPT(interrupts);
580 if (tval)
581 brcmuart_tx_isr(up, tval);
582 if ((rval | tval) == 0)
583 dev_warn(dev, "Spurious interrupt: 0x%x\n", interrupts);
584
585 spin_unlock_irqrestore(&up->lock, flags);
586 return IRQ_HANDLED;
587}
588
589static int brcmuart_startup(struct uart_port *port)
590{
591 int res;
592 struct uart_8250_port *up = up_to_u8250p(port);
593 struct brcmuart_priv *priv = up->port.private_data;
594
595 priv->shutdown = false;
596
597
598
599
600
601 up->dma = NULL;
602
603 res = serial8250_do_startup(port);
604 if (!priv->dma_enabled)
605 return res;
606
607
608
609
610 up->ier &= ~UART_IER_RDI;
611 serial_port_out(port, UART_IER, up->ier);
612
613 priv->tx_running = false;
614 priv->dma.rx_dma = NULL;
615 priv->dma.tx_dma = brcmuart_tx_dma;
616 up->dma = &priv->dma;
617
618 brcmuart_init_dma_hardware(priv);
619 start_rx_dma(up);
620 return res;
621}
622
623static void brcmuart_shutdown(struct uart_port *port)
624{
625 struct uart_8250_port *up = up_to_u8250p(port);
626 struct brcmuart_priv *priv = up->port.private_data;
627 unsigned long flags;
628
629 spin_lock_irqsave(&port->lock, flags);
630 priv->shutdown = true;
631 if (priv->dma_enabled) {
632 stop_rx_dma(up);
633 stop_tx_dma(up);
634
635 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET,
636 UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS);
637 }
638
639
640
641
642
643 up->dma = NULL;
644
645 spin_unlock_irqrestore(&port->lock, flags);
646 serial8250_do_shutdown(port);
647}
648
649
650
651
652
653static void init_real_clk_rates(struct device *dev, struct brcmuart_priv *priv)
654{
655 int x;
656 int rc;
657
658 priv->default_mux_rate = clk_get_rate(priv->baud_mux_clk);
659 for (x = 0; x < ARRAY_SIZE(priv->real_rates); x++) {
660 if (priv->rate_table[x] == 0) {
661 priv->real_rates[x] = 0;
662 continue;
663 }
664 rc = clk_set_rate(priv->baud_mux_clk, priv->rate_table[x]);
665 if (rc) {
666 dev_err(dev, "Error selecting BAUD MUX clock for %u\n",
667 priv->rate_table[x]);
668 priv->real_rates[x] = priv->rate_table[x];
669 } else {
670 priv->real_rates[x] = clk_get_rate(priv->baud_mux_clk);
671 }
672 }
673 clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);
674}
675
676static void set_clock_mux(struct uart_port *up, struct brcmuart_priv *priv,
677 u32 baud)
678{
679 u32 percent;
680 u32 best_percent = UINT_MAX;
681 u32 quot;
682 u32 best_quot = 1;
683 u32 rate;
684 int best_index = -1;
685 u64 hires_rate;
686 u64 hires_baud;
687 u64 hires_err;
688 int rc;
689 int i;
690 int real_baud;
691
692
693 if (priv->baud_mux_clk == NULL)
694 return;
695
696
697 for (i = 0; i < ARRAY_SIZE(priv->real_rates); i++) {
698 if (priv->real_rates[i] == 0)
699 continue;
700 rate = priv->real_rates[i] / 16;
701 quot = DIV_ROUND_CLOSEST(rate, baud);
702 if (!quot)
703 continue;
704
705
706 hires_rate = (u64)rate * 10000;
707 hires_baud = (u64)baud * 10000;
708
709 hires_err = div_u64(hires_rate, (u64)quot);
710
711
712 if (hires_err > hires_baud)
713 hires_err = (hires_err - hires_baud);
714 else
715 hires_err = (hires_baud - hires_err);
716
717 percent = (unsigned long)DIV_ROUND_CLOSEST_ULL(hires_err, baud);
718 dev_dbg(up->dev,
719 "Baud rate: %u, MUX Clk: %u, Error: %u.%u%%\n",
720 baud, priv->real_rates[i], percent / 100,
721 percent % 100);
722 if (percent < best_percent) {
723 best_percent = percent;
724 best_index = i;
725 best_quot = quot;
726 }
727 }
728 if (best_index == -1) {
729 dev_err(up->dev, "Error, %d BAUD rate is too fast.\n", baud);
730 return;
731 }
732 rate = priv->real_rates[best_index];
733 rc = clk_set_rate(priv->baud_mux_clk, rate);
734 if (rc)
735 dev_err(up->dev, "Error selecting BAUD MUX clock\n");
736
737
738 if (best_percent > 300)
739 dev_err(up->dev, "Error, baud: %d has %u.%u%% error\n",
740 baud, percent / 100, percent % 100);
741
742 real_baud = rate / 16 / best_quot;
743 dev_dbg(up->dev, "Selecting BAUD MUX rate: %u\n", rate);
744 dev_dbg(up->dev, "Requested baud: %u, Actual baud: %u\n",
745 baud, real_baud);
746
747
748 i = NSEC_PER_SEC / real_baud / 10;
749 i += (i / 2);
750 priv->char_wait = ns_to_ktime(i);
751
752 up->uartclk = rate;
753}
754
755static void brcmstb_set_termios(struct uart_port *up,
756 struct ktermios *termios,
757 struct ktermios *old)
758{
759 struct uart_8250_port *p8250 = up_to_u8250p(up);
760 struct brcmuart_priv *priv = up->private_data;
761
762 if (priv->dma_enabled)
763 stop_rx_dma(p8250);
764 set_clock_mux(up, priv, tty_termios_baud_rate(termios));
765 serial8250_do_set_termios(up, termios, old);
766 if (p8250->mcr & UART_MCR_AFE)
767 p8250->port.status |= UPSTAT_AUTOCTS;
768 if (priv->dma_enabled)
769 start_rx_dma(p8250);
770}
771
772static int brcmuart_handle_irq(struct uart_port *p)
773{
774 unsigned int iir = serial_port_in(p, UART_IIR);
775 struct brcmuart_priv *priv = p->private_data;
776 struct uart_8250_port *up = up_to_u8250p(p);
777 unsigned int status;
778 unsigned long flags;
779 unsigned int ier;
780 unsigned int mcr;
781 int handled = 0;
782
783
784
785
786
787 if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) {
788 spin_lock_irqsave(&p->lock, flags);
789 status = serial_port_in(p, UART_LSR);
790 if ((status & UART_LSR_DR) == 0) {
791
792 ier = serial_port_in(p, UART_IER);
793
794
795
796
797
798
799 if ((ier & UART_IER_RDI) && (up->mcr & UART_MCR_AFE)) {
800 ier &= ~(UART_IER_RLSI | UART_IER_RDI);
801 serial_port_out(p, UART_IER, ier);
802 mcr = serial_port_in(p, UART_MCR);
803 mcr &= ~UART_MCR_RTS;
804 serial_port_out(p, UART_MCR, mcr);
805 hrtimer_start(&priv->hrt, priv->char_wait,
806 HRTIMER_MODE_REL);
807 } else {
808 serial_port_in(p, UART_RX);
809 }
810
811 handled = 1;
812 }
813 spin_unlock_irqrestore(&p->lock, flags);
814 if (handled)
815 return 1;
816 }
817 return serial8250_handle_irq(p, iir);
818}
819
820static enum hrtimer_restart brcmuart_hrtimer_func(struct hrtimer *t)
821{
822 struct brcmuart_priv *priv = container_of(t, struct brcmuart_priv, hrt);
823 struct uart_port *p = priv->up;
824 struct uart_8250_port *up = up_to_u8250p(p);
825 unsigned int status;
826 unsigned long flags;
827
828 if (priv->shutdown)
829 return HRTIMER_NORESTART;
830
831 spin_lock_irqsave(&p->lock, flags);
832 status = serial_port_in(p, UART_LSR);
833
834
835
836
837
838 if ((status & UART_LSR_DR) == 0) {
839 serial_port_in(p, UART_RX);
840 priv->rx_bad_timeout_no_char++;
841 } else {
842 priv->rx_bad_timeout_late_char++;
843 }
844
845
846 if ((up->ier & (UART_IER_RLSI | UART_IER_RDI)) ==
847 (UART_IER_RLSI | UART_IER_RDI)) {
848 status = serial_port_in(p, UART_IER);
849 status |= (UART_IER_RLSI | UART_IER_RDI);
850 serial_port_out(p, UART_IER, status);
851 status = serial_port_in(p, UART_MCR);
852 status |= UART_MCR_RTS;
853 serial_port_out(p, UART_MCR, status);
854 }
855 spin_unlock_irqrestore(&p->lock, flags);
856 return HRTIMER_NORESTART;
857}
858
859static const struct of_device_id brcmuart_dt_ids[] = {
860 {
861 .compatible = "brcm,bcm7278-uart",
862 .data = brcmstb_rate_table_7278,
863 },
864 {
865 .compatible = "brcm,bcm7271-uart",
866 .data = brcmstb_rate_table,
867 },
868 {},
869};
870
871MODULE_DEVICE_TABLE(of, brcmuart_dt_ids);
872
873static void brcmuart_free_bufs(struct device *dev, struct brcmuart_priv *priv)
874{
875 if (priv->rx_bufs)
876 dma_free_coherent(dev, priv->rx_size, priv->rx_bufs,
877 priv->rx_addr);
878 if (priv->tx_buf)
879 dma_free_coherent(dev, priv->tx_size, priv->tx_buf,
880 priv->tx_addr);
881}
882
883static void brcmuart_throttle(struct uart_port *port)
884{
885 struct brcmuart_priv *priv = port->private_data;
886
887 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, UDMA_RX_INTERRUPTS);
888}
889
890static void brcmuart_unthrottle(struct uart_port *port)
891{
892 struct brcmuart_priv *priv = port->private_data;
893
894 udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR,
895 UDMA_RX_INTERRUPTS);
896}
897
898static int debugfs_stats_show(struct seq_file *s, void *unused)
899{
900 struct brcmuart_priv *priv = s->private;
901
902 seq_printf(s, "rx_err:\t\t\t\t%u\n",
903 priv->rx_err);
904 seq_printf(s, "rx_timeout:\t\t\t%u\n",
905 priv->rx_timeout);
906 seq_printf(s, "rx_abort:\t\t\t%u\n",
907 priv->rx_abort);
908 seq_printf(s, "rx_bad_timeout_late_char:\t%u\n",
909 priv->rx_bad_timeout_late_char);
910 seq_printf(s, "rx_bad_timeout_no_char:\t\t%u\n",
911 priv->rx_bad_timeout_no_char);
912 seq_printf(s, "rx_missing_close_timeout:\t%u\n",
913 priv->rx_missing_close_timeout);
914 if (priv->dma_enabled) {
915 seq_printf(s, "dma_rx_partial_buf:\t\t%llu\n",
916 priv->dma_rx_partial_buf);
917 seq_printf(s, "dma_rx_full_buf:\t\t%llu\n",
918 priv->dma_rx_full_buf);
919 }
920 return 0;
921}
922DEFINE_SHOW_ATTRIBUTE(debugfs_stats);
923
924static void brcmuart_init_debugfs(struct brcmuart_priv *priv,
925 const char *device)
926{
927 priv->debugfs_dir = debugfs_create_dir(device, brcmuart_debugfs_root);
928 debugfs_create_file("stats", 0444, priv->debugfs_dir, priv,
929 &debugfs_stats_fops);
930}
931
932
933static int brcmuart_probe(struct platform_device *pdev)
934{
935 struct resource *regs;
936 struct device_node *np = pdev->dev.of_node;
937 const struct of_device_id *of_id = NULL;
938 struct uart_8250_port *new_port;
939 struct device *dev = &pdev->dev;
940 struct brcmuart_priv *priv;
941 struct clk *baud_mux_clk;
942 struct uart_8250_port up;
943 struct resource *irq;
944 void __iomem *membase = 0;
945 resource_size_t mapbase = 0;
946 u32 clk_rate = 0;
947 int ret;
948 int x;
949 int dma_irq;
950 static const char * const reg_names[REGS_MAX] = {
951 "uart", "dma_rx", "dma_tx", "dma_intr2", "dma_arb"
952 };
953
954 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
955 if (!irq) {
956 dev_err(dev, "missing irq\n");
957 return -EINVAL;
958 }
959 priv = devm_kzalloc(dev, sizeof(struct brcmuart_priv),
960 GFP_KERNEL);
961 if (!priv)
962 return -ENOMEM;
963
964 of_id = of_match_node(brcmuart_dt_ids, np);
965 if (!of_id || !of_id->data)
966 priv->rate_table = brcmstb_rate_table;
967 else
968 priv->rate_table = of_id->data;
969
970 for (x = 0; x < REGS_MAX; x++) {
971 regs = platform_get_resource_byname(pdev, IORESOURCE_MEM,
972 reg_names[x]);
973 if (!regs)
974 break;
975 priv->regs[x] = devm_ioremap(dev, regs->start,
976 resource_size(regs));
977 if (!priv->regs[x])
978 return -ENOMEM;
979 if (x == REGS_8250) {
980 mapbase = regs->start;
981 membase = priv->regs[x];
982 }
983 }
984
985
986 if (x != 1 && x != REGS_MAX) {
987 dev_warn(dev, "%s registers not specified\n", reg_names[x]);
988 return -EINVAL;
989 }
990
991
992 if (x > REGS_DMA_RX) {
993 if (brcmuart_arbitration(priv, 1) == 0) {
994 u32 txrev = 0;
995 u32 rxrev = 0;
996
997 txrev = udma_readl(priv, REGS_DMA_RX, UDMA_RX_REVISION);
998 rxrev = udma_readl(priv, REGS_DMA_TX, UDMA_TX_REVISION);
999 if ((txrev >= UDMA_TX_REVISION_REQUIRED) &&
1000 (rxrev >= UDMA_RX_REVISION_REQUIRED)) {
1001
1002
1003 priv->dma_enabled = true;
1004 } else {
1005 brcmuart_arbitration(priv, 0);
1006 dev_err(dev,
1007 "Unsupported DMA Hardware Revision\n");
1008 }
1009 } else {
1010 dev_err(dev,
1011 "Timeout arbitrating for UART DMA hardware\n");
1012 }
1013 }
1014
1015 of_property_read_u32(np, "clock-frequency", &clk_rate);
1016
1017
1018 baud_mux_clk = of_clk_get_by_name(np, "sw_baud");
1019 if (IS_ERR(baud_mux_clk)) {
1020 if (PTR_ERR(baud_mux_clk) == -EPROBE_DEFER)
1021 return -EPROBE_DEFER;
1022 dev_dbg(dev, "BAUD MUX clock not specified\n");
1023 } else {
1024 dev_dbg(dev, "BAUD MUX clock found\n");
1025 ret = clk_prepare_enable(baud_mux_clk);
1026 if (ret)
1027 return ret;
1028 priv->baud_mux_clk = baud_mux_clk;
1029 init_real_clk_rates(dev, priv);
1030 clk_rate = priv->default_mux_rate;
1031 }
1032
1033 if (clk_rate == 0) {
1034 dev_err(dev, "clock-frequency or clk not defined\n");
1035 return -EINVAL;
1036 }
1037
1038 dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not ");
1039
1040 memset(&up, 0, sizeof(up));
1041 up.port.type = PORT_16550A;
1042 up.port.uartclk = clk_rate;
1043 up.port.dev = dev;
1044 up.port.mapbase = mapbase;
1045 up.port.membase = membase;
1046 up.port.irq = irq->start;
1047 up.port.handle_irq = brcmuart_handle_irq;
1048 up.port.regshift = 2;
1049 up.port.iotype = of_device_is_big_endian(np) ?
1050 UPIO_MEM32BE : UPIO_MEM32;
1051 up.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF
1052 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
1053 up.port.dev = dev;
1054 up.port.private_data = priv;
1055 up.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
1056 up.port.fifosize = 32;
1057
1058
1059 ret = of_alias_get_id(np, "serial");
1060 if (ret >= 0)
1061 up.port.line = ret;
1062
1063
1064 hrtimer_init(&priv->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
1065 priv->hrt.function = brcmuart_hrtimer_func;
1066
1067 up.port.shutdown = brcmuart_shutdown;
1068 up.port.startup = brcmuart_startup;
1069 up.port.throttle = brcmuart_throttle;
1070 up.port.unthrottle = brcmuart_unthrottle;
1071 up.port.set_termios = brcmstb_set_termios;
1072
1073 if (priv->dma_enabled) {
1074 priv->rx_size = RX_BUF_SIZE * RX_BUFS_COUNT;
1075 priv->rx_bufs = dma_alloc_coherent(dev,
1076 priv->rx_size,
1077 &priv->rx_addr, GFP_KERNEL);
1078 if (!priv->rx_bufs)
1079 goto err;
1080 priv->tx_size = UART_XMIT_SIZE;
1081 priv->tx_buf = dma_alloc_coherent(dev,
1082 priv->tx_size,
1083 &priv->tx_addr, GFP_KERNEL);
1084 if (!priv->tx_buf)
1085 goto err;
1086 }
1087
1088 ret = serial8250_register_8250_port(&up);
1089 if (ret < 0) {
1090 dev_err(dev, "unable to register 8250 port\n");
1091 goto err;
1092 }
1093 priv->line = ret;
1094 new_port = serial8250_get_port(ret);
1095 priv->up = &new_port->port;
1096 if (priv->dma_enabled) {
1097 dma_irq = platform_get_irq_byname(pdev, "dma");
1098 if (dma_irq < 0) {
1099 dev_err(dev, "no IRQ resource info\n");
1100 goto err1;
1101 }
1102 ret = devm_request_irq(dev, dma_irq, brcmuart_isr,
1103 IRQF_SHARED, "uart DMA irq", &new_port->port);
1104 if (ret) {
1105 dev_err(dev, "unable to register IRQ handler\n");
1106 goto err1;
1107 }
1108 }
1109 platform_set_drvdata(pdev, priv);
1110 brcmuart_init_debugfs(priv, dev_name(&pdev->dev));
1111 return 0;
1112
1113err1:
1114 serial8250_unregister_port(priv->line);
1115err:
1116 brcmuart_free_bufs(dev, priv);
1117 brcmuart_arbitration(priv, 0);
1118 return -ENODEV;
1119}
1120
1121static int brcmuart_remove(struct platform_device *pdev)
1122{
1123 struct brcmuart_priv *priv = platform_get_drvdata(pdev);
1124
1125 debugfs_remove_recursive(priv->debugfs_dir);
1126 hrtimer_cancel(&priv->hrt);
1127 serial8250_unregister_port(priv->line);
1128 brcmuart_free_bufs(&pdev->dev, priv);
1129 brcmuart_arbitration(priv, 0);
1130 return 0;
1131}
1132
1133static int __maybe_unused brcmuart_suspend(struct device *dev)
1134{
1135 struct brcmuart_priv *priv = dev_get_drvdata(dev);
1136
1137 serial8250_suspend_port(priv->line);
1138 clk_disable_unprepare(priv->baud_mux_clk);
1139
1140 return 0;
1141}
1142
1143static int __maybe_unused brcmuart_resume(struct device *dev)
1144{
1145 struct brcmuart_priv *priv = dev_get_drvdata(dev);
1146 int ret;
1147
1148 ret = clk_prepare_enable(priv->baud_mux_clk);
1149 if (ret)
1150 dev_err(dev, "Error enabling BAUD MUX clock\n");
1151
1152
1153
1154
1155
1156 ret = clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate);
1157 if (ret)
1158 dev_err(dev, "Error restoring default BAUD MUX clock\n");
1159 if (priv->dma_enabled) {
1160 if (brcmuart_arbitration(priv, 1)) {
1161 dev_err(dev, "Timeout arbitrating for DMA hardware on resume\n");
1162 return(-EBUSY);
1163 }
1164 brcmuart_init_dma_hardware(priv);
1165 start_rx_dma(serial8250_get_port(priv->line));
1166 }
1167 serial8250_resume_port(priv->line);
1168 return 0;
1169}
1170
1171static const struct dev_pm_ops brcmuart_dev_pm_ops = {
1172 SET_SYSTEM_SLEEP_PM_OPS(brcmuart_suspend, brcmuart_resume)
1173};
1174
1175static struct platform_driver brcmuart_platform_driver = {
1176 .driver = {
1177 .name = "bcm7271-uart",
1178 .pm = &brcmuart_dev_pm_ops,
1179 .of_match_table = brcmuart_dt_ids,
1180 },
1181 .probe = brcmuart_probe,
1182 .remove = brcmuart_remove,
1183};
1184
1185static int __init brcmuart_init(void)
1186{
1187 brcmuart_debugfs_root = debugfs_create_dir(
1188 brcmuart_platform_driver.driver.name, NULL);
1189 return platform_driver_register(&brcmuart_platform_driver);
1190}
1191module_init(brcmuart_init);
1192
1193static void __exit brcmuart_deinit(void)
1194{
1195 platform_driver_unregister(&brcmuart_platform_driver);
1196 debugfs_remove_recursive(brcmuart_debugfs_root);
1197}
1198module_exit(brcmuart_deinit);
1199
1200MODULE_AUTHOR("Al Cooper");
1201MODULE_DESCRIPTION("Broadcom NS16550A compatible serial port driver");
1202MODULE_LICENSE("GPL v2");
1203
