xref: /linux/drivers/net/can/peak_canfd/peak_pciefd_main.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 /*
2  * Copyright (C) 2007, 2011 Wolfgang Grandegger <wg@grandegger.com>
3  * Copyright (C) 2012 Stephane Grosjean <s.grosjean@peak-system.com>
4  *
5  * Derived from the PCAN project file driver/src/pcan_pci.c:
6  *
7  * Copyright (C) 2001-2006  PEAK System-Technik GmbH
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the version 2 of the GNU General Public License
11  * as published by the Free Software Foundation
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  */
18 
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/interrupt.h>
22 #include <linux/netdevice.h>
23 #include <linux/delay.h>
24 #include <linux/pci.h>
25 #include <linux/io.h>
26 #include <linux/can.h>
27 #include <linux/can/dev.h>
28 
29 #include "peak_canfd_user.h"
30 
31 MODULE_AUTHOR("Stephane Grosjean <s.grosjean@peak-system.com>");
32 MODULE_DESCRIPTION("Socket-CAN driver for PEAK PCAN PCIe/M.2 FD family cards");
33 MODULE_SUPPORTED_DEVICE("PEAK PCAN PCIe/M.2 FD CAN cards");
34 MODULE_LICENSE("GPL v2");
35 
36 #define PCIEFD_DRV_NAME		"peak_pciefd"
37 
38 #define PEAK_PCI_VENDOR_ID	0x001c	/* The PCI device and vendor IDs */
39 #define PEAK_PCIEFD_ID		0x0013	/* for PCIe slot cards */
40 #define PCAN_CPCIEFD_ID		0x0014	/* for Compact-PCI Serial slot cards */
41 #define PCAN_PCIE104FD_ID	0x0017	/* for PCIe-104 Express slot cards */
42 #define PCAN_MINIPCIEFD_ID      0x0018	/* for mini-PCIe slot cards */
43 #define PCAN_PCIEFD_OEM_ID      0x0019	/* for PCIe slot OEM cards */
44 #define PCAN_M2_ID		0x001a	/* for M2 slot cards */
45 
46 /* PEAK PCIe board access description */
47 #define PCIEFD_BAR0_SIZE		(64 * 1024)
48 #define PCIEFD_RX_DMA_SIZE		(4 * 1024)
49 #define PCIEFD_TX_DMA_SIZE		(4 * 1024)
50 
51 #define PCIEFD_TX_PAGE_SIZE		(2 * 1024)
52 
53 /* System Control Registers */
54 #define PCIEFD_REG_SYS_CTL_SET		0x0000	/* set bits */
55 #define PCIEFD_REG_SYS_CTL_CLR		0x0004	/* clear bits */
56 
57 /* Version info registers */
58 #define PCIEFD_REG_SYS_VER1		0x0040	/* version reg #1 */
59 #define PCIEFD_REG_SYS_VER2		0x0044	/* version reg #2 */
60 
61 #define PCIEFD_FW_VERSION(x, y, z)	(((u32)(x) << 24) | \
62 					 ((u32)(y) << 16) | \
63 					 ((u32)(z) << 8))
64 
65 /* System Control Registers Bits */
66 #define PCIEFD_SYS_CTL_TS_RST		0x00000001	/* timestamp clock */
67 #define PCIEFD_SYS_CTL_CLK_EN		0x00000002	/* system clock */
68 
69 /* CAN-FD channel addresses */
70 #define PCIEFD_CANX_OFF(c)		(((c) + 1) * 0x1000)
71 
72 #define PCIEFD_ECHO_SKB_MAX		PCANFD_ECHO_SKB_DEF
73 
74 /* CAN-FD channel registers */
75 #define PCIEFD_REG_CAN_MISC		0x0000	/* Misc. control */
76 #define PCIEFD_REG_CAN_CLK_SEL		0x0008	/* Clock selector */
77 #define PCIEFD_REG_CAN_CMD_PORT_L	0x0010	/* 64-bits command port */
78 #define PCIEFD_REG_CAN_CMD_PORT_H	0x0014
79 #define PCIEFD_REG_CAN_TX_REQ_ACC	0x0020	/* Tx request accumulator */
80 #define PCIEFD_REG_CAN_TX_CTL_SET	0x0030	/* Tx control set register */
81 #define PCIEFD_REG_CAN_TX_CTL_CLR	0x0038	/* Tx control clear register */
82 #define PCIEFD_REG_CAN_TX_DMA_ADDR_L	0x0040	/* 64-bits addr for Tx DMA */
83 #define PCIEFD_REG_CAN_TX_DMA_ADDR_H	0x0044
84 #define PCIEFD_REG_CAN_RX_CTL_SET	0x0050	/* Rx control set register */
85 #define PCIEFD_REG_CAN_RX_CTL_CLR	0x0058	/* Rx control clear register */
86 #define PCIEFD_REG_CAN_RX_CTL_WRT	0x0060	/* Rx control write register */
87 #define PCIEFD_REG_CAN_RX_CTL_ACK	0x0068	/* Rx control ACK register */
88 #define PCIEFD_REG_CAN_RX_DMA_ADDR_L	0x0070	/* 64-bits addr for Rx DMA */
89 #define PCIEFD_REG_CAN_RX_DMA_ADDR_H	0x0074
90 
91 /* CAN-FD channel misc register bits */
92 #define CANFD_MISC_TS_RST		0x00000001	/* timestamp cnt rst */
93 
94 /* CAN-FD channel Clock SELector Source & DIVider */
95 #define CANFD_CLK_SEL_DIV_MASK		0x00000007
96 #define CANFD_CLK_SEL_DIV_60MHZ		0x00000000	/* SRC=240MHz only */
97 #define CANFD_CLK_SEL_DIV_40MHZ		0x00000001	/* SRC=240MHz only */
98 #define CANFD_CLK_SEL_DIV_30MHZ		0x00000002	/* SRC=240MHz only */
99 #define CANFD_CLK_SEL_DIV_24MHZ		0x00000003	/* SRC=240MHz only */
100 #define CANFD_CLK_SEL_DIV_20MHZ		0x00000004	/* SRC=240MHz only */
101 
102 #define CANFD_CLK_SEL_SRC_MASK		0x00000008	/* 0=80MHz, 1=240MHz */
103 #define CANFD_CLK_SEL_SRC_240MHZ	0x00000008
104 #define CANFD_CLK_SEL_SRC_80MHZ		(~CANFD_CLK_SEL_SRC_240MHZ & \
105 							CANFD_CLK_SEL_SRC_MASK)
106 
107 #define CANFD_CLK_SEL_20MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
108 						CANFD_CLK_SEL_DIV_20MHZ)
109 #define CANFD_CLK_SEL_24MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
110 						CANFD_CLK_SEL_DIV_24MHZ)
111 #define CANFD_CLK_SEL_30MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
112 						CANFD_CLK_SEL_DIV_30MHZ)
113 #define CANFD_CLK_SEL_40MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
114 						CANFD_CLK_SEL_DIV_40MHZ)
115 #define CANFD_CLK_SEL_60MHZ		(CANFD_CLK_SEL_SRC_240MHZ |\
116 						CANFD_CLK_SEL_DIV_60MHZ)
117 #define CANFD_CLK_SEL_80MHZ		(CANFD_CLK_SEL_SRC_80MHZ)
118 
119 /* CAN-FD channel Rx/Tx control register bits */
120 #define CANFD_CTL_UNC_BIT		0x00010000	/* Uncached DMA mem */
121 #define CANFD_CTL_RST_BIT		0x00020000	/* reset DMA action */
122 #define CANFD_CTL_IEN_BIT		0x00040000	/* IRQ enable */
123 
124 /* Rx IRQ Count and Time Limits */
125 #define CANFD_CTL_IRQ_CL_DEF	16	/* Rx msg max nb per IRQ in Rx DMA */
126 #define CANFD_CTL_IRQ_TL_DEF	10	/* Time before IRQ if < CL (x100 µs) */
127 
128 #define CANFD_OPTIONS_SET	(CANFD_OPTION_ERROR | CANFD_OPTION_BUSLOAD)
129 
130 /* Tx anticipation window (link logical address should be aligned on 2K
131  * boundary)
132  */
133 #define PCIEFD_TX_PAGE_COUNT	(PCIEFD_TX_DMA_SIZE / PCIEFD_TX_PAGE_SIZE)
134 
135 #define CANFD_MSG_LNK_TX	0x1001	/* Tx msgs link */
136 
137 /* 32-bits IRQ status fields, heading Rx DMA area */
138 static inline int pciefd_irq_tag(u32 irq_status)
139 {
140 	return irq_status & 0x0000000f;
141 }
142 
143 static inline int pciefd_irq_rx_cnt(u32 irq_status)
144 {
145 	return (irq_status & 0x000007f0) >> 4;
146 }
147 
148 static inline int pciefd_irq_is_lnk(u32 irq_status)
149 {
150 	return irq_status & 0x00010000;
151 }
152 
153 /* Rx record */
154 struct pciefd_rx_dma {
155 	__le32 irq_status;
156 	__le32 sys_time_low;
157 	__le32 sys_time_high;
158 	struct pucan_rx_msg msg[0];
159 } __packed __aligned(4);
160 
161 /* Tx Link record */
162 struct pciefd_tx_link {
163 	__le16 size;
164 	__le16 type;
165 	__le32 laddr_lo;
166 	__le32 laddr_hi;
167 } __packed __aligned(4);
168 
169 /* Tx page descriptor */
170 struct pciefd_page {
171 	void *vbase;			/* page virtual address */
172 	dma_addr_t lbase;		/* page logical address */
173 	u32 offset;
174 	u32 size;
175 };
176 
177 /* CAN-FD channel object */
178 struct pciefd_board;
179 struct pciefd_can {
180 	struct peak_canfd_priv ucan;	/* must be the first member */
181 	void __iomem *reg_base;		/* channel config base addr */
182 	struct pciefd_board *board;	/* reverse link */
183 
184 	struct pucan_command pucan_cmd;	/* command buffer */
185 
186 	dma_addr_t rx_dma_laddr;	/* DMA virtual and logical addr */
187 	void *rx_dma_vaddr;		/* for Rx and Tx areas */
188 	dma_addr_t tx_dma_laddr;
189 	void *tx_dma_vaddr;
190 
191 	struct pciefd_page tx_pages[PCIEFD_TX_PAGE_COUNT];
192 	u16 tx_pages_free;		/* free Tx pages counter */
193 	u16 tx_page_index;		/* current page used for Tx */
194 	spinlock_t tx_lock;
195 
196 	u32 irq_status;
197 	u32 irq_tag;				/* next irq tag */
198 };
199 
200 /* PEAK-PCIe FD board object */
201 struct pciefd_board {
202 	void __iomem *reg_base;
203 	struct pci_dev *pci_dev;
204 	int can_count;
205 	spinlock_t cmd_lock;		/* 64-bits cmds must be atomic */
206 	struct pciefd_can *can[0];	/* array of network devices */
207 };
208 
209 /* supported device ids. */
210 static const struct pci_device_id peak_pciefd_tbl[] = {
211 	{PEAK_PCI_VENDOR_ID, PEAK_PCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
212 	{PEAK_PCI_VENDOR_ID, PCAN_CPCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
213 	{PEAK_PCI_VENDOR_ID, PCAN_PCIE104FD_ID, PCI_ANY_ID, PCI_ANY_ID,},
214 	{PEAK_PCI_VENDOR_ID, PCAN_MINIPCIEFD_ID, PCI_ANY_ID, PCI_ANY_ID,},
215 	{PEAK_PCI_VENDOR_ID, PCAN_PCIEFD_OEM_ID, PCI_ANY_ID, PCI_ANY_ID,},
216 	{PEAK_PCI_VENDOR_ID, PCAN_M2_ID, PCI_ANY_ID, PCI_ANY_ID,},
217 	{0,}
218 };
219 
220 MODULE_DEVICE_TABLE(pci, peak_pciefd_tbl);
221 
222 /* read a 32 bits value from a SYS block register */
223 static inline u32 pciefd_sys_readreg(const struct pciefd_board *priv, u16 reg)
224 {
225 	return readl(priv->reg_base + reg);
226 }
227 
228 /* write a 32 bits value into a SYS block register */
229 static inline void pciefd_sys_writereg(const struct pciefd_board *priv,
230 				       u32 val, u16 reg)
231 {
232 	writel(val, priv->reg_base + reg);
233 }
234 
235 /* read a 32 bits value from CAN-FD block register */
236 static inline u32 pciefd_can_readreg(const struct pciefd_can *priv, u16 reg)
237 {
238 	return readl(priv->reg_base + reg);
239 }
240 
241 /* write a 32 bits value into a CAN-FD block register */
242 static inline void pciefd_can_writereg(const struct pciefd_can *priv,
243 				       u32 val, u16 reg)
244 {
245 	writel(val, priv->reg_base + reg);
246 }
247 
248 /* give a channel logical Rx DMA address to the board */
249 static void pciefd_can_setup_rx_dma(struct pciefd_can *priv)
250 {
251 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
252 	const u32 dma_addr_h = (u32)(priv->rx_dma_laddr >> 32);
253 #else
254 	const u32 dma_addr_h = 0;
255 #endif
256 
257 	/* (DMA must be reset for Rx) */
258 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_RX_CTL_SET);
259 
260 	/* write the logical address of the Rx DMA area for this channel */
261 	pciefd_can_writereg(priv, (u32)priv->rx_dma_laddr,
262 			    PCIEFD_REG_CAN_RX_DMA_ADDR_L);
263 	pciefd_can_writereg(priv, dma_addr_h, PCIEFD_REG_CAN_RX_DMA_ADDR_H);
264 
265 	/* also indicates that Rx DMA is cacheable */
266 	pciefd_can_writereg(priv, CANFD_CTL_UNC_BIT, PCIEFD_REG_CAN_RX_CTL_CLR);
267 }
268 
269 /* clear channel logical Rx DMA address from the board */
270 static void pciefd_can_clear_rx_dma(struct pciefd_can *priv)
271 {
272 	/* DMA must be reset for Rx */
273 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_RX_CTL_SET);
274 
275 	/* clear the logical address of the Rx DMA area for this channel */
276 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_RX_DMA_ADDR_L);
277 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_RX_DMA_ADDR_H);
278 }
279 
280 /* give a channel logical Tx DMA address to the board */
281 static void pciefd_can_setup_tx_dma(struct pciefd_can *priv)
282 {
283 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
284 	const u32 dma_addr_h = (u32)(priv->tx_dma_laddr >> 32);
285 #else
286 	const u32 dma_addr_h = 0;
287 #endif
288 
289 	/* (DMA must be reset for Tx) */
290 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_SET);
291 
292 	/* write the logical address of the Tx DMA area for this channel */
293 	pciefd_can_writereg(priv, (u32)priv->tx_dma_laddr,
294 			    PCIEFD_REG_CAN_TX_DMA_ADDR_L);
295 	pciefd_can_writereg(priv, dma_addr_h, PCIEFD_REG_CAN_TX_DMA_ADDR_H);
296 
297 	/* also indicates that Tx DMA is cacheable */
298 	pciefd_can_writereg(priv, CANFD_CTL_UNC_BIT, PCIEFD_REG_CAN_TX_CTL_CLR);
299 }
300 
301 /* clear channel logical Tx DMA address from the board */
302 static void pciefd_can_clear_tx_dma(struct pciefd_can *priv)
303 {
304 	/* DMA must be reset for Tx */
305 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_SET);
306 
307 	/* clear the logical address of the Tx DMA area for this channel */
308 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_TX_DMA_ADDR_L);
309 	pciefd_can_writereg(priv, 0, PCIEFD_REG_CAN_TX_DMA_ADDR_H);
310 }
311 
312 static void pciefd_can_ack_rx_dma(struct pciefd_can *priv)
313 {
314 	/* read value of current IRQ tag and inc it for next one */
315 	priv->irq_tag = le32_to_cpu(*(__le32 *)priv->rx_dma_vaddr);
316 	priv->irq_tag++;
317 	priv->irq_tag &= 0xf;
318 
319 	/* write the next IRQ tag for this CAN */
320 	pciefd_can_writereg(priv, priv->irq_tag, PCIEFD_REG_CAN_RX_CTL_ACK);
321 }
322 
323 /* IRQ handler */
324 static irqreturn_t pciefd_irq_handler(int irq, void *arg)
325 {
326 	struct pciefd_can *priv = arg;
327 	struct pciefd_rx_dma *rx_dma = priv->rx_dma_vaddr;
328 
329 	/* INTA mode only to sync with PCIe transaction */
330 	if (!pci_dev_msi_enabled(priv->board->pci_dev))
331 		(void)pciefd_sys_readreg(priv->board, PCIEFD_REG_SYS_VER1);
332 
333 	/* read IRQ status from the first 32-bits of the Rx DMA area */
334 	priv->irq_status = le32_to_cpu(rx_dma->irq_status);
335 
336 	/* check if this (shared) IRQ is for this CAN */
337 	if (pciefd_irq_tag(priv->irq_status) != priv->irq_tag)
338 		return IRQ_NONE;
339 
340 	/* handle rx messages (if any) */
341 	peak_canfd_handle_msgs_list(&priv->ucan,
342 				    rx_dma->msg,
343 				    pciefd_irq_rx_cnt(priv->irq_status));
344 
345 	/* handle tx link interrupt (if any) */
346 	if (pciefd_irq_is_lnk(priv->irq_status)) {
347 		unsigned long flags;
348 
349 		spin_lock_irqsave(&priv->tx_lock, flags);
350 		priv->tx_pages_free++;
351 		spin_unlock_irqrestore(&priv->tx_lock, flags);
352 
353 		/* wake producer up (only if enough room in echo_skb array) */
354 		spin_lock_irqsave(&priv->ucan.echo_lock, flags);
355 		if (!priv->ucan.can.echo_skb[priv->ucan.echo_idx])
356 			netif_wake_queue(priv->ucan.ndev);
357 
358 		spin_unlock_irqrestore(&priv->ucan.echo_lock, flags);
359 	}
360 
361 	/* re-enable Rx DMA transfer for this CAN */
362 	pciefd_can_ack_rx_dma(priv);
363 
364 	return IRQ_HANDLED;
365 }
366 
367 static int pciefd_enable_tx_path(struct peak_canfd_priv *ucan)
368 {
369 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
370 	int i;
371 
372 	/* initialize the Tx pages descriptors */
373 	priv->tx_pages_free = PCIEFD_TX_PAGE_COUNT - 1;
374 	priv->tx_page_index = 0;
375 
376 	priv->tx_pages[0].vbase = priv->tx_dma_vaddr;
377 	priv->tx_pages[0].lbase = priv->tx_dma_laddr;
378 
379 	for (i = 0; i < PCIEFD_TX_PAGE_COUNT; i++) {
380 		priv->tx_pages[i].offset = 0;
381 		priv->tx_pages[i].size = PCIEFD_TX_PAGE_SIZE -
382 					 sizeof(struct pciefd_tx_link);
383 		if (i) {
384 			priv->tx_pages[i].vbase =
385 					  priv->tx_pages[i - 1].vbase +
386 					  PCIEFD_TX_PAGE_SIZE;
387 			priv->tx_pages[i].lbase =
388 					  priv->tx_pages[i - 1].lbase +
389 					  PCIEFD_TX_PAGE_SIZE;
390 		}
391 	}
392 
393 	/* setup Tx DMA addresses into IP core */
394 	pciefd_can_setup_tx_dma(priv);
395 
396 	/* start (TX_RST=0) Tx Path */
397 	pciefd_can_writereg(priv, CANFD_CTL_RST_BIT, PCIEFD_REG_CAN_TX_CTL_CLR);
398 
399 	return 0;
400 }
401 
402 /* board specific CANFD command pre-processing */
403 static int pciefd_pre_cmd(struct peak_canfd_priv *ucan)
404 {
405 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
406 	u16 cmd = pucan_cmd_get_opcode(&priv->pucan_cmd);
407 	int err;
408 
409 	/* pre-process command */
410 	switch (cmd) {
411 	case PUCAN_CMD_NORMAL_MODE:
412 	case PUCAN_CMD_LISTEN_ONLY_MODE:
413 
414 		if (ucan->can.state == CAN_STATE_BUS_OFF)
415 			break;
416 
417 		/* going into operational mode: setup IRQ handler */
418 		err = request_irq(priv->ucan.ndev->irq,
419 				  pciefd_irq_handler,
420 				  IRQF_SHARED,
421 				  PCIEFD_DRV_NAME,
422 				  priv);
423 		if (err)
424 			return err;
425 
426 		/* setup Rx DMA address */
427 		pciefd_can_setup_rx_dma(priv);
428 
429 		/* setup max count of msgs per IRQ */
430 		pciefd_can_writereg(priv, (CANFD_CTL_IRQ_TL_DEF) << 8 |
431 				    CANFD_CTL_IRQ_CL_DEF,
432 				    PCIEFD_REG_CAN_RX_CTL_WRT);
433 
434 		/* clear DMA RST for Rx (Rx start) */
435 		pciefd_can_writereg(priv, CANFD_CTL_RST_BIT,
436 				    PCIEFD_REG_CAN_RX_CTL_CLR);
437 
438 		/* reset timestamps */
439 		pciefd_can_writereg(priv, !CANFD_MISC_TS_RST,
440 				    PCIEFD_REG_CAN_MISC);
441 
442 		/* do an initial ACK */
443 		pciefd_can_ack_rx_dma(priv);
444 
445 		/* enable IRQ for this CAN after having set next irq_tag */
446 		pciefd_can_writereg(priv, CANFD_CTL_IEN_BIT,
447 				    PCIEFD_REG_CAN_RX_CTL_SET);
448 
449 		/* Tx path will be setup as soon as RX_BARRIER is received */
450 		break;
451 	default:
452 		break;
453 	}
454 
455 	return 0;
456 }
457 
458 /* write a command */
459 static int pciefd_write_cmd(struct peak_canfd_priv *ucan)
460 {
461 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
462 	unsigned long flags;
463 
464 	/* 64-bits command is atomic */
465 	spin_lock_irqsave(&priv->board->cmd_lock, flags);
466 
467 	pciefd_can_writereg(priv, *(u32 *)ucan->cmd_buffer,
468 			    PCIEFD_REG_CAN_CMD_PORT_L);
469 	pciefd_can_writereg(priv, *(u32 *)(ucan->cmd_buffer + 4),
470 			    PCIEFD_REG_CAN_CMD_PORT_H);
471 
472 	spin_unlock_irqrestore(&priv->board->cmd_lock, flags);
473 
474 	return 0;
475 }
476 
477 /* board specific CANFD command post-processing */
478 static int pciefd_post_cmd(struct peak_canfd_priv *ucan)
479 {
480 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
481 	u16 cmd = pucan_cmd_get_opcode(&priv->pucan_cmd);
482 
483 	switch (cmd) {
484 	case PUCAN_CMD_RESET_MODE:
485 
486 		if (ucan->can.state == CAN_STATE_STOPPED)
487 			break;
488 
489 		/* controller now in reset mode: */
490 
491 		/* disable IRQ for this CAN */
492 		pciefd_can_writereg(priv, CANFD_CTL_IEN_BIT,
493 				    PCIEFD_REG_CAN_RX_CTL_CLR);
494 
495 		/* stop and reset DMA addresses in Tx/Rx engines */
496 		pciefd_can_clear_tx_dma(priv);
497 		pciefd_can_clear_rx_dma(priv);
498 
499 		/* wait for above commands to complete (read cycle) */
500 		(void)pciefd_sys_readreg(priv->board, PCIEFD_REG_SYS_VER1);
501 
502 		free_irq(priv->ucan.ndev->irq, priv);
503 
504 		ucan->can.state = CAN_STATE_STOPPED;
505 
506 		break;
507 	}
508 
509 	return 0;
510 }
511 
512 static void *pciefd_alloc_tx_msg(struct peak_canfd_priv *ucan, u16 msg_size,
513 				 int *room_left)
514 {
515 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
516 	struct pciefd_page *page = priv->tx_pages + priv->tx_page_index;
517 	unsigned long flags;
518 	void *msg;
519 
520 	spin_lock_irqsave(&priv->tx_lock, flags);
521 
522 	if (page->offset + msg_size > page->size) {
523 		struct pciefd_tx_link *lk;
524 
525 		/* not enough space in this page: try another one */
526 		if (!priv->tx_pages_free) {
527 			spin_unlock_irqrestore(&priv->tx_lock, flags);
528 
529 			/* Tx overflow */
530 			return NULL;
531 		}
532 
533 		priv->tx_pages_free--;
534 
535 		/* keep address of the very last free slot of current page */
536 		lk = page->vbase + page->offset;
537 
538 		/* next, move on a new free page */
539 		priv->tx_page_index = (priv->tx_page_index + 1) %
540 				      PCIEFD_TX_PAGE_COUNT;
541 		page = priv->tx_pages + priv->tx_page_index;
542 
543 		/* put link record to this new page at the end of prev one */
544 		lk->size = cpu_to_le16(sizeof(*lk));
545 		lk->type = cpu_to_le16(CANFD_MSG_LNK_TX);
546 		lk->laddr_lo = cpu_to_le32(page->lbase);
547 
548 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
549 		lk->laddr_hi = cpu_to_le32(page->lbase >> 32);
550 #else
551 		lk->laddr_hi = 0;
552 #endif
553 		/* next msgs will be put from the begininng of this new page */
554 		page->offset = 0;
555 	}
556 
557 	*room_left = priv->tx_pages_free * page->size;
558 
559 	spin_unlock_irqrestore(&priv->tx_lock, flags);
560 
561 	msg = page->vbase + page->offset;
562 
563 	/* give back room left in the tx ring */
564 	*room_left += page->size - (page->offset + msg_size);
565 
566 	return msg;
567 }
568 
569 static int pciefd_write_tx_msg(struct peak_canfd_priv *ucan,
570 			       struct pucan_tx_msg *msg)
571 {
572 	struct pciefd_can *priv = (struct pciefd_can *)ucan;
573 	struct pciefd_page *page = priv->tx_pages + priv->tx_page_index;
574 
575 	/* this slot is now reserved for writing the frame */
576 	page->offset += le16_to_cpu(msg->size);
577 
578 	/* tell the board a frame has been written in Tx DMA area */
579 	pciefd_can_writereg(priv, 1, PCIEFD_REG_CAN_TX_REQ_ACC);
580 
581 	return 0;
582 }
583 
584 /* probe for CAN-FD channel #pciefd_board->can_count */
585 static int pciefd_can_probe(struct pciefd_board *pciefd)
586 {
587 	struct net_device *ndev;
588 	struct pciefd_can *priv;
589 	u32 clk;
590 	int err;
591 
592 	/* allocate the candev object with default isize of echo skbs ring */
593 	ndev = alloc_peak_canfd_dev(sizeof(*priv), pciefd->can_count,
594 				    PCIEFD_ECHO_SKB_MAX);
595 	if (!ndev) {
596 		dev_err(&pciefd->pci_dev->dev,
597 			"failed to alloc candev object\n");
598 		goto failure;
599 	}
600 
601 	priv = netdev_priv(ndev);
602 
603 	/* fill-in candev private object: */
604 
605 	/* setup PCIe-FD own callbacks */
606 	priv->ucan.pre_cmd = pciefd_pre_cmd;
607 	priv->ucan.write_cmd = pciefd_write_cmd;
608 	priv->ucan.post_cmd = pciefd_post_cmd;
609 	priv->ucan.enable_tx_path = pciefd_enable_tx_path;
610 	priv->ucan.alloc_tx_msg = pciefd_alloc_tx_msg;
611 	priv->ucan.write_tx_msg = pciefd_write_tx_msg;
612 
613 	/* setup PCIe-FD own command buffer */
614 	priv->ucan.cmd_buffer = &priv->pucan_cmd;
615 	priv->ucan.cmd_maxlen = sizeof(priv->pucan_cmd);
616 
617 	priv->board = pciefd;
618 
619 	/* CAN config regs block address */
620 	priv->reg_base = pciefd->reg_base + PCIEFD_CANX_OFF(priv->ucan.index);
621 
622 	/* allocate non-cacheable DMA'able 4KB memory area for Rx */
623 	priv->rx_dma_vaddr = dmam_alloc_coherent(&pciefd->pci_dev->dev,
624 						 PCIEFD_RX_DMA_SIZE,
625 						 &priv->rx_dma_laddr,
626 						 GFP_KERNEL);
627 	if (!priv->rx_dma_vaddr) {
628 		dev_err(&pciefd->pci_dev->dev,
629 			"Rx dmam_alloc_coherent(%u) failure\n",
630 			PCIEFD_RX_DMA_SIZE);
631 		goto err_free_candev;
632 	}
633 
634 	/* allocate non-cacheable DMA'able 4KB memory area for Tx */
635 	priv->tx_dma_vaddr = dmam_alloc_coherent(&pciefd->pci_dev->dev,
636 						 PCIEFD_TX_DMA_SIZE,
637 						 &priv->tx_dma_laddr,
638 						 GFP_KERNEL);
639 	if (!priv->tx_dma_vaddr) {
640 		dev_err(&pciefd->pci_dev->dev,
641 			"Tx dmam_alloc_coherent(%u) failure\n",
642 			PCIEFD_TX_DMA_SIZE);
643 		goto err_free_candev;
644 	}
645 
646 	/* CAN clock in RST mode */
647 	pciefd_can_writereg(priv, CANFD_MISC_TS_RST, PCIEFD_REG_CAN_MISC);
648 
649 	/* read current clock value */
650 	clk = pciefd_can_readreg(priv, PCIEFD_REG_CAN_CLK_SEL);
651 	switch (clk) {
652 	case CANFD_CLK_SEL_20MHZ:
653 		priv->ucan.can.clock.freq = 20 * 1000 * 1000;
654 		break;
655 	case CANFD_CLK_SEL_24MHZ:
656 		priv->ucan.can.clock.freq = 24 * 1000 * 1000;
657 		break;
658 	case CANFD_CLK_SEL_30MHZ:
659 		priv->ucan.can.clock.freq = 30 * 1000 * 1000;
660 		break;
661 	case CANFD_CLK_SEL_40MHZ:
662 		priv->ucan.can.clock.freq = 40 * 1000 * 1000;
663 		break;
664 	case CANFD_CLK_SEL_60MHZ:
665 		priv->ucan.can.clock.freq = 60 * 1000 * 1000;
666 		break;
667 	default:
668 		pciefd_can_writereg(priv, CANFD_CLK_SEL_80MHZ,
669 				    PCIEFD_REG_CAN_CLK_SEL);
670 
671 		/* fallthough */
672 	case CANFD_CLK_SEL_80MHZ:
673 		priv->ucan.can.clock.freq = 80 * 1000 * 1000;
674 		break;
675 	}
676 
677 	ndev->irq = pciefd->pci_dev->irq;
678 
679 	SET_NETDEV_DEV(ndev, &pciefd->pci_dev->dev);
680 
681 	err = register_candev(ndev);
682 	if (err) {
683 		dev_err(&pciefd->pci_dev->dev,
684 			"couldn't register CAN device: %d\n", err);
685 		goto err_free_candev;
686 	}
687 
688 	spin_lock_init(&priv->tx_lock);
689 
690 	/* save the object address in the board structure */
691 	pciefd->can[pciefd->can_count] = priv;
692 
693 	dev_info(&pciefd->pci_dev->dev, "%s at reg_base=0x%p irq=%d\n",
694 		 ndev->name, priv->reg_base, ndev->irq);
695 
696 	return 0;
697 
698 err_free_candev:
699 	free_candev(ndev);
700 
701 failure:
702 	return -ENOMEM;
703 }
704 
705 /* remove a CAN-FD channel by releasing all of its resources */
706 static void pciefd_can_remove(struct pciefd_can *priv)
707 {
708 	/* unregister (close) the can device to go back to RST mode first */
709 	unregister_candev(priv->ucan.ndev);
710 
711 	/* finally, free the candev object */
712 	free_candev(priv->ucan.ndev);
713 }
714 
715 /* remove all CAN-FD channels by releasing their own resources */
716 static void pciefd_can_remove_all(struct pciefd_board *pciefd)
717 {
718 	while (pciefd->can_count > 0)
719 		pciefd_can_remove(pciefd->can[--pciefd->can_count]);
720 }
721 
722 /* probe for the entire device */
723 static int peak_pciefd_probe(struct pci_dev *pdev,
724 			     const struct pci_device_id *ent)
725 {
726 	struct pciefd_board *pciefd;
727 	int err, can_count;
728 	u16 sub_sys_id;
729 	u8 hw_ver_major;
730 	u8 hw_ver_minor;
731 	u8 hw_ver_sub;
732 	u32 v2;
733 
734 	err = pci_enable_device(pdev);
735 	if (err)
736 		return err;
737 	err = pci_request_regions(pdev, PCIEFD_DRV_NAME);
738 	if (err)
739 		goto err_disable_pci;
740 
741 	/* the number of channels depends on sub-system id */
742 	err = pci_read_config_word(pdev, PCI_SUBSYSTEM_ID, &sub_sys_id);
743 	if (err)
744 		goto err_release_regions;
745 
746 	dev_dbg(&pdev->dev, "probing device %04x:%04x:%04x\n",
747 		pdev->vendor, pdev->device, sub_sys_id);
748 
749 	if (sub_sys_id >= 0x0012)
750 		can_count = 4;
751 	else if (sub_sys_id >= 0x0010)
752 		can_count = 3;
753 	else if (sub_sys_id >= 0x0004)
754 		can_count = 2;
755 	else
756 		can_count = 1;
757 
758 	/* allocate board structure object */
759 	pciefd = devm_kzalloc(&pdev->dev, struct_size(pciefd, can, can_count),
760 			      GFP_KERNEL);
761 	if (!pciefd) {
762 		err = -ENOMEM;
763 		goto err_release_regions;
764 	}
765 
766 	/* initialize the board structure */
767 	pciefd->pci_dev = pdev;
768 	spin_lock_init(&pciefd->cmd_lock);
769 
770 	/* save the PCI BAR0 virtual address for further system regs access */
771 	pciefd->reg_base = pci_iomap(pdev, 0, PCIEFD_BAR0_SIZE);
772 	if (!pciefd->reg_base) {
773 		dev_err(&pdev->dev, "failed to map PCI resource #0\n");
774 		err = -ENOMEM;
775 		goto err_release_regions;
776 	}
777 
778 	/* read the firmware version number */
779 	v2 = pciefd_sys_readreg(pciefd, PCIEFD_REG_SYS_VER2);
780 
781 	hw_ver_major = (v2 & 0x0000f000) >> 12;
782 	hw_ver_minor = (v2 & 0x00000f00) >> 8;
783 	hw_ver_sub = (v2 & 0x000000f0) >> 4;
784 
785 	dev_info(&pdev->dev,
786 		 "%ux CAN-FD PCAN-PCIe FPGA v%u.%u.%u:\n", can_count,
787 		 hw_ver_major, hw_ver_minor, hw_ver_sub);
788 
789 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
790 	/* FW < v3.3.0 DMA logic doesn't handle correctly the mix of 32-bit and
791 	 * 64-bit logical addresses: this workaround forces usage of 32-bit
792 	 * DMA addresses only when such a fw is detected.
793 	 */
794 	if (PCIEFD_FW_VERSION(hw_ver_major, hw_ver_minor, hw_ver_sub) <
795 	    PCIEFD_FW_VERSION(3, 3, 0)) {
796 		err = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
797 		if (err)
798 			dev_warn(&pdev->dev,
799 				 "warning: can't set DMA mask %llxh (err %d)\n",
800 				 DMA_BIT_MASK(32), err);
801 	}
802 #endif
803 
804 	/* stop system clock */
805 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_CLK_EN,
806 			    PCIEFD_REG_SYS_CTL_CLR);
807 
808 	pci_set_master(pdev);
809 
810 	/* create now the corresponding channels objects */
811 	while (pciefd->can_count < can_count) {
812 		err = pciefd_can_probe(pciefd);
813 		if (err)
814 			goto err_free_canfd;
815 
816 		pciefd->can_count++;
817 	}
818 
819 	/* set system timestamps counter in RST mode */
820 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_TS_RST,
821 			    PCIEFD_REG_SYS_CTL_SET);
822 
823 	/* wait a bit (read cycle) */
824 	(void)pciefd_sys_readreg(pciefd, PCIEFD_REG_SYS_VER1);
825 
826 	/* free all clocks */
827 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_TS_RST,
828 			    PCIEFD_REG_SYS_CTL_CLR);
829 
830 	/* start system clock */
831 	pciefd_sys_writereg(pciefd, PCIEFD_SYS_CTL_CLK_EN,
832 			    PCIEFD_REG_SYS_CTL_SET);
833 
834 	/* remember the board structure address in the device user data */
835 	pci_set_drvdata(pdev, pciefd);
836 
837 	return 0;
838 
839 err_free_canfd:
840 	pciefd_can_remove_all(pciefd);
841 
842 	pci_iounmap(pdev, pciefd->reg_base);
843 
844 err_release_regions:
845 	pci_release_regions(pdev);
846 
847 err_disable_pci:
848 	pci_disable_device(pdev);
849 
850 	/* pci_xxx_config_word() return positive PCIBIOS_xxx error codes while
851 	 * the probe() function must return a negative errno in case of failure
852 	 * (err is unchanged if negative) */
853 	return pcibios_err_to_errno(err);
854 }
855 
856 /* free the board structure object, as well as its resources: */
857 static void peak_pciefd_remove(struct pci_dev *pdev)
858 {
859 	struct pciefd_board *pciefd = pci_get_drvdata(pdev);
860 
861 	/* release CAN-FD channels resources */
862 	pciefd_can_remove_all(pciefd);
863 
864 	pci_iounmap(pdev, pciefd->reg_base);
865 
866 	pci_release_regions(pdev);
867 	pci_disable_device(pdev);
868 }
869 
870 static struct pci_driver peak_pciefd_driver = {
871 	.name = PCIEFD_DRV_NAME,
872 	.id_table = peak_pciefd_tbl,
873 	.probe = peak_pciefd_probe,
874 	.remove = peak_pciefd_remove,
875 };
876 
877 module_pci_driver(peak_pciefd_driver);
878