1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 */
4
5 /*
6 * Both AR2315 and AR2316 chips have PCI interface unit, which supports DMA
7 * and interrupt. PCI interface supports MMIO access method, but does not
8 * seem to support I/O ports.
9 *
10 * Read/write operation in the region 0x80000000-0xBFFFFFFF causes
11 * a memory read/write command on the PCI bus. 30 LSBs of address on
12 * the bus are taken from memory read/write request and 2 MSBs are
13 * determined by PCI unit configuration.
14 *
15 * To work with the configuration space instead of memory is necessary set
16 * the CFG_SEL bit in the PCI_MISC_CONFIG register.
17 *
18 * Devices on the bus can perform DMA requests via chip BAR1. PCI host
19 * controller BARs are programmed as if an external device is programmed.
20 * Which means that during configuration, IDSEL pin of the chip should be
21 * asserted.
22 *
23 * We know (and support) only one board that uses the PCI interface -
24 * Fonera 2.0g (FON2202). It has a USB EHCI controller connected to the
25 * AR2315 PCI bus. IDSEL pin of USB controller is connected to AD[13] line
26 * and IDSEL pin of AR2315 is connected to AD[16] line.
27 */
28
29 #include <linux/types.h>
30 #include <linux/pci.h>
31 #include <linux/platform_device.h>
32 #include <linux/kernel.h>
33 #include <linux/init.h>
34 #include <linux/dma-direct.h>
35 #include <linux/mm.h>
36 #include <linux/delay.h>
37 #include <linux/bitops.h>
38 #include <linux/irq.h>
39 #include <linux/irqdomain.h>
40 #include <linux/io.h>
41 #include <asm/paccess.h>
42
43 /*
44 * PCI Bus Interface Registers
45 */
46 #define AR2315_PCI_1MS_REG 0x0008
47
48 #define AR2315_PCI_1MS_MASK 0x3FFFF /* # of AHB clk cycles in 1ms */
49
50 #define AR2315_PCI_MISC_CONFIG 0x000c
51
52 #define AR2315_PCIMISC_TXD_EN 0x00000001 /* Enable TXD for fragments */
53 #define AR2315_PCIMISC_CFG_SEL 0x00000002 /* Mem or Config cycles */
54 #define AR2315_PCIMISC_GIG_MASK 0x0000000C /* bits 31-30 for pci req */
55 #define AR2315_PCIMISC_RST_MODE 0x00000030
56 #define AR2315_PCIRST_INPUT 0x00000000 /* 4:5=0 rst is input */
57 #define AR2315_PCIRST_LOW 0x00000010 /* 4:5=1 rst to GND */
58 #define AR2315_PCIRST_HIGH 0x00000020 /* 4:5=2 rst to VDD */
59 #define AR2315_PCIGRANT_EN 0x00000000 /* 6:7=0 early grant en */
60 #define AR2315_PCIGRANT_FRAME 0x00000040 /* 6:7=1 grant waits 4 frame */
61 #define AR2315_PCIGRANT_IDLE 0x00000080 /* 6:7=2 grant waits 4 idle */
62 #define AR2315_PCIGRANT_GAP 0x00000000 /* 6:7=2 grant waits 4 idle */
63 #define AR2315_PCICACHE_DIS 0x00001000 /* PCI external access cache
64 * disable */
65
66 #define AR2315_PCI_OUT_TSTAMP 0x0010
67
68 #define AR2315_PCI_UNCACHE_CFG 0x0014
69
70 #define AR2315_PCI_IN_EN 0x0100
71
72 #define AR2315_PCI_IN_EN0 0x01 /* Enable chain 0 */
73 #define AR2315_PCI_IN_EN1 0x02 /* Enable chain 1 */
74 #define AR2315_PCI_IN_EN2 0x04 /* Enable chain 2 */
75 #define AR2315_PCI_IN_EN3 0x08 /* Enable chain 3 */
76
77 #define AR2315_PCI_IN_DIS 0x0104
78
79 #define AR2315_PCI_IN_DIS0 0x01 /* Disable chain 0 */
80 #define AR2315_PCI_IN_DIS1 0x02 /* Disable chain 1 */
81 #define AR2315_PCI_IN_DIS2 0x04 /* Disable chain 2 */
82 #define AR2315_PCI_IN_DIS3 0x08 /* Disable chain 3 */
83
84 #define AR2315_PCI_IN_PTR 0x0200
85
86 #define AR2315_PCI_OUT_EN 0x0400
87
88 #define AR2315_PCI_OUT_EN0 0x01 /* Enable chain 0 */
89
90 #define AR2315_PCI_OUT_DIS 0x0404
91
92 #define AR2315_PCI_OUT_DIS0 0x01 /* Disable chain 0 */
93
94 #define AR2315_PCI_OUT_PTR 0x0408
95
96 /* PCI interrupt status (write one to clear) */
97 #define AR2315_PCI_ISR 0x0500
98
99 #define AR2315_PCI_INT_TX 0x00000001 /* Desc In Completed */
100 #define AR2315_PCI_INT_TXOK 0x00000002 /* Desc In OK */
101 #define AR2315_PCI_INT_TXERR 0x00000004 /* Desc In ERR */
102 #define AR2315_PCI_INT_TXEOL 0x00000008 /* Desc In End-of-List */
103 #define AR2315_PCI_INT_RX 0x00000010 /* Desc Out Completed */
104 #define AR2315_PCI_INT_RXOK 0x00000020 /* Desc Out OK */
105 #define AR2315_PCI_INT_RXERR 0x00000040 /* Desc Out ERR */
106 #define AR2315_PCI_INT_RXEOL 0x00000080 /* Desc Out EOL */
107 #define AR2315_PCI_INT_TXOOD 0x00000200 /* Desc In Out-of-Desc */
108 #define AR2315_PCI_INT_DESCMASK 0x0000FFFF /* Desc Mask */
109 #define AR2315_PCI_INT_EXT 0x02000000 /* Extern PCI INTA */
110 #define AR2315_PCI_INT_ABORT 0x04000000 /* PCI bus abort event */
111
112 /* PCI interrupt mask */
113 #define AR2315_PCI_IMR 0x0504
114
115 /* Global PCI interrupt enable */
116 #define AR2315_PCI_IER 0x0508
117
118 #define AR2315_PCI_IER_DISABLE 0x00 /* disable pci interrupts */
119 #define AR2315_PCI_IER_ENABLE 0x01 /* enable pci interrupts */
120
121 #define AR2315_PCI_HOST_IN_EN 0x0800
122 #define AR2315_PCI_HOST_IN_DIS 0x0804
123 #define AR2315_PCI_HOST_IN_PTR 0x0810
124 #define AR2315_PCI_HOST_OUT_EN 0x0900
125 #define AR2315_PCI_HOST_OUT_DIS 0x0904
126 #define AR2315_PCI_HOST_OUT_PTR 0x0908
127
128 /*
129 * PCI interrupts, which share IP5
130 * Keep ordered according to AR2315_PCI_INT_XXX bits
131 */
132 #define AR2315_PCI_IRQ_EXT 25
133 #define AR2315_PCI_IRQ_ABORT 26
134 #define AR2315_PCI_IRQ_COUNT 27
135
136 /* Arbitrary size of memory region to access the configuration space */
137 #define AR2315_PCI_CFG_SIZE 0x00100000
138
139 #define AR2315_PCI_HOST_SLOT 3
140 #define AR2315_PCI_HOST_DEVID ((0xff18 << 16) | PCI_VENDOR_ID_ATHEROS)
141
142 /*
143 * We need some arbitrary non-zero value to be programmed to the BAR1 register
144 * of PCI host controller to enable DMA. The same value should be used as the
145 * offset to calculate the physical address of DMA buffer for PCI devices.
146 */
147 #define AR2315_PCI_HOST_SDRAM_BASEADDR 0x20000000
148
149 /* ??? access BAR */
150 #define AR2315_PCI_HOST_MBAR0 0x10000000
151 /* RAM access BAR */
152 #define AR2315_PCI_HOST_MBAR1 AR2315_PCI_HOST_SDRAM_BASEADDR
153 /* ??? access BAR */
154 #define AR2315_PCI_HOST_MBAR2 0x30000000
155
156 struct ar2315_pci_ctrl {
157 void __iomem *cfg_mem;
158 void __iomem *mmr_mem;
159 unsigned irq;
160 unsigned irq_ext;
161 struct irq_domain *domain;
162 struct pci_controller pci_ctrl;
163 struct resource mem_res;
164 struct resource io_res;
165 };
166
167 static inline dma_addr_t ar2315_dev_offset(struct device *dev)
168 {
169 if (dev && dev_is_pci(dev))
170 return AR2315_PCI_HOST_SDRAM_BASEADDR;
171 return 0;
172 }
173
174 dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
175 {
176 return paddr + ar2315_dev_offset(dev);
177 }
178
179 phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
180 {
181 return dma_addr - ar2315_dev_offset(dev);
182 }
183
184 static inline struct ar2315_pci_ctrl *ar2315_pci_bus_to_apc(struct pci_bus *bus)
185 {
186 struct pci_controller *hose = bus->sysdata;
187
188 return container_of(hose, struct ar2315_pci_ctrl, pci_ctrl);
189 }
190
191 static inline u32 ar2315_pci_reg_read(struct ar2315_pci_ctrl *apc, u32 reg)
192 {
193 return __raw_readl(apc->mmr_mem + reg);
194 }
195
196 static inline void ar2315_pci_reg_write(struct ar2315_pci_ctrl *apc, u32 reg,
197 u32 val)
198 {
199 __raw_writel(val, apc->mmr_mem + reg);
200 }
201
202 static inline void ar2315_pci_reg_mask(struct ar2315_pci_ctrl *apc, u32 reg,
203 u32 mask, u32 val)
204 {
205 u32 ret = ar2315_pci_reg_read(apc, reg);
206
207 ret &= ~mask;
208 ret |= val;
209 ar2315_pci_reg_write(apc, reg, ret);
210 }
211
212 static int ar2315_pci_cfg_access(struct ar2315_pci_ctrl *apc, unsigned devfn,
213 int where, int size, u32 *ptr, bool write)
214 {
215 int func = PCI_FUNC(devfn);
216 int dev = PCI_SLOT(devfn);
217 u32 addr = (1 << (13 + dev)) | (func << 8) | (where & ~3);
218 u32 mask = 0xffffffff >> 8 * (4 - size);
219 u32 sh = (where & 3) * 8;
220 u32 value, isr;
221
222 /* Prevent access past the remapped area */
223 if (addr >= AR2315_PCI_CFG_SIZE || dev > 18)
224 return PCIBIOS_DEVICE_NOT_FOUND;
225
226 /* Clear pending errors */
227 ar2315_pci_reg_write(apc, AR2315_PCI_ISR, AR2315_PCI_INT_ABORT);
228 /* Select Configuration access */
229 ar2315_pci_reg_mask(apc, AR2315_PCI_MISC_CONFIG, 0,
230 AR2315_PCIMISC_CFG_SEL);
231
232 mb(); /* PCI must see space change before we begin */
233
234 value = __raw_readl(apc->cfg_mem + addr);
235
236 isr = ar2315_pci_reg_read(apc, AR2315_PCI_ISR);
237
238 if (isr & AR2315_PCI_INT_ABORT)
239 goto exit_err;
240
241 if (write) {
242 value = (value & ~(mask << sh)) | *ptr << sh;
243 __raw_writel(value, apc->cfg_mem + addr);
244 isr = ar2315_pci_reg_read(apc, AR2315_PCI_ISR);
245 if (isr & AR2315_PCI_INT_ABORT)
246 goto exit_err;
247 } else {
248 *ptr = (value >> sh) & mask;
249 }
250
251 goto exit;
252
253 exit_err:
254 ar2315_pci_reg_write(apc, AR2315_PCI_ISR, AR2315_PCI_INT_ABORT);
255 if (!write)
256 *ptr = 0xffffffff;
257
258 exit:
259 /* Select Memory access */
260 ar2315_pci_reg_mask(apc, AR2315_PCI_MISC_CONFIG, AR2315_PCIMISC_CFG_SEL,
261 0);
262
263 return isr & AR2315_PCI_INT_ABORT ? PCIBIOS_DEVICE_NOT_FOUND :
264 PCIBIOS_SUCCESSFUL;
265 }
266
267 static inline int ar2315_pci_local_cfg_rd(struct ar2315_pci_ctrl *apc,
268 unsigned devfn, int where, u32 *val)
269 {
270 return ar2315_pci_cfg_access(apc, devfn, where, sizeof(u32), val,
271 false);
272 }
273
274 static inline int ar2315_pci_local_cfg_wr(struct ar2315_pci_ctrl *apc,
275 unsigned devfn, int where, u32 val)
276 {
277 return ar2315_pci_cfg_access(apc, devfn, where, sizeof(u32), &val,
278 true);
279 }
280
281 static int ar2315_pci_cfg_read(struct pci_bus *bus, unsigned devfn, int where,
282 int size, u32 *value)
283 {
284 struct ar2315_pci_ctrl *apc = ar2315_pci_bus_to_apc(bus);
285
286 if (PCI_SLOT(devfn) == AR2315_PCI_HOST_SLOT)
287 return PCIBIOS_DEVICE_NOT_FOUND;
288
289 return ar2315_pci_cfg_access(apc, devfn, where, size, value, false);
290 }
291
292 static int ar2315_pci_cfg_write(struct pci_bus *bus, unsigned devfn, int where,
293 int size, u32 value)
294 {
295 struct ar2315_pci_ctrl *apc = ar2315_pci_bus_to_apc(bus);
296
297 if (PCI_SLOT(devfn) == AR2315_PCI_HOST_SLOT)
298 return PCIBIOS_DEVICE_NOT_FOUND;
299
300 return ar2315_pci_cfg_access(apc, devfn, where, size, &value, true);
301 }
302
303 static struct pci_ops ar2315_pci_ops = {
304 .read = ar2315_pci_cfg_read,
305 .write = ar2315_pci_cfg_write,
306 };
307
308 static int ar2315_pci_host_setup(struct ar2315_pci_ctrl *apc)
309 {
310 unsigned devfn = PCI_DEVFN(AR2315_PCI_HOST_SLOT, 0);
311 int res;
312 u32 id;
313
314 res = ar2315_pci_local_cfg_rd(apc, devfn, PCI_VENDOR_ID, &id);
315 if (res != PCIBIOS_SUCCESSFUL || id != AR2315_PCI_HOST_DEVID)
316 return -ENODEV;
317
318 /* Program MBARs */
319 ar2315_pci_local_cfg_wr(apc, devfn, PCI_BASE_ADDRESS_0,
320 AR2315_PCI_HOST_MBAR0);
321 ar2315_pci_local_cfg_wr(apc, devfn, PCI_BASE_ADDRESS_1,
322 AR2315_PCI_HOST_MBAR1);
323 ar2315_pci_local_cfg_wr(apc, devfn, PCI_BASE_ADDRESS_2,
324 AR2315_PCI_HOST_MBAR2);
325
326 /* Run */
327 ar2315_pci_local_cfg_wr(apc, devfn, PCI_COMMAND, PCI_COMMAND_MEMORY |
328 PCI_COMMAND_MASTER | PCI_COMMAND_SPECIAL |
329 PCI_COMMAND_INVALIDATE | PCI_COMMAND_PARITY |
330 PCI_COMMAND_SERR | PCI_COMMAND_FAST_BACK);
331
332 return 0;
333 }
334
335 static void ar2315_pci_irq_handler(struct irq_desc *desc)
336 {
337 struct ar2315_pci_ctrl *apc = irq_desc_get_handler_data(desc);
338 u32 pending = ar2315_pci_reg_read(apc, AR2315_PCI_ISR) &
339 ar2315_pci_reg_read(apc, AR2315_PCI_IMR);
340 int ret = 0;
341
342 if (pending)
343 ret = generic_handle_domain_irq(apc->domain, __ffs(pending));
344
345 if (!pending || ret)
346 spurious_interrupt();
347 }
348
349 static void ar2315_pci_irq_mask(struct irq_data *d)
350 {
351 struct ar2315_pci_ctrl *apc = irq_data_get_irq_chip_data(d);
352
353 ar2315_pci_reg_mask(apc, AR2315_PCI_IMR, BIT(d->hwirq), 0);
354 }
355
356 static void ar2315_pci_irq_mask_ack(struct irq_data *d)
357 {
358 struct ar2315_pci_ctrl *apc = irq_data_get_irq_chip_data(d);
359 u32 m = BIT(d->hwirq);
360
361 ar2315_pci_reg_mask(apc, AR2315_PCI_IMR, m, 0);
362 ar2315_pci_reg_write(apc, AR2315_PCI_ISR, m);
363 }
364
365 static void ar2315_pci_irq_unmask(struct irq_data *d)
366 {
367 struct ar2315_pci_ctrl *apc = irq_data_get_irq_chip_data(d);
368
369 ar2315_pci_reg_mask(apc, AR2315_PCI_IMR, 0, BIT(d->hwirq));
370 }
371
372 static struct irq_chip ar2315_pci_irq_chip = {
373 .name = "AR2315-PCI",
374 .irq_mask = ar2315_pci_irq_mask,
375 .irq_mask_ack = ar2315_pci_irq_mask_ack,
376 .irq_unmask = ar2315_pci_irq_unmask,
377 };
378
379 static int ar2315_pci_irq_map(struct irq_domain *d, unsigned irq,
380 irq_hw_number_t hw)
381 {
382 irq_set_chip_and_handler(irq, &ar2315_pci_irq_chip, handle_level_irq);
383 irq_set_chip_data(irq, d->host_data);
384 return 0;
385 }
386
387 static const struct irq_domain_ops ar2315_pci_irq_domain_ops = {
388 .map = ar2315_pci_irq_map,
389 };
390
391 static void ar2315_pci_irq_init(struct ar2315_pci_ctrl *apc)
392 {
393 ar2315_pci_reg_mask(apc, AR2315_PCI_IER, AR2315_PCI_IER_ENABLE, 0);
394 ar2315_pci_reg_mask(apc, AR2315_PCI_IMR, (AR2315_PCI_INT_ABORT |
395 AR2315_PCI_INT_EXT), 0);
396
397 apc->irq_ext = irq_create_mapping(apc->domain, AR2315_PCI_IRQ_EXT);
398
399 irq_set_chained_handler_and_data(apc->irq, ar2315_pci_irq_handler,
400 apc);
401
402 /* Clear any pending Abort or external Interrupts
403 * and enable interrupt processing */
404 ar2315_pci_reg_write(apc, AR2315_PCI_ISR, AR2315_PCI_INT_ABORT |
405 AR2315_PCI_INT_EXT);
406 ar2315_pci_reg_mask(apc, AR2315_PCI_IER, 0, AR2315_PCI_IER_ENABLE);
407 }
408
409 static int ar2315_pci_probe(struct platform_device *pdev)
410 {
411 struct ar2315_pci_ctrl *apc;
412 struct device *dev = &pdev->dev;
413 struct resource *res;
414 int irq, err;
415
416 apc = devm_kzalloc(dev, sizeof(*apc), GFP_KERNEL);
417 if (!apc)
418 return -ENOMEM;
419
420 irq = platform_get_irq(pdev, 0);
421 if (irq < 0)
422 return -EINVAL;
423 apc->irq = irq;
424
425 apc->mmr_mem = devm_platform_ioremap_resource_byname(pdev,
426 "ar2315-pci-ctrl");
427 if (IS_ERR(apc->mmr_mem))
428 return PTR_ERR(apc->mmr_mem);
429
430 res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
431 "ar2315-pci-ext");
432 if (!res)
433 return -EINVAL;
434
435 apc->mem_res.name = "AR2315 PCI mem space";
436 apc->mem_res.parent = res;
437 apc->mem_res.start = res->start;
438 apc->mem_res.end = res->end;
439 apc->mem_res.flags = IORESOURCE_MEM;
440
441 /* Remap PCI config space */
442 apc->cfg_mem = devm_ioremap(dev, res->start,
443 AR2315_PCI_CFG_SIZE);
444 if (!apc->cfg_mem) {
445 dev_err(dev, "failed to remap PCI config space\n");
446 return -ENOMEM;
447 }
448
449 /* Reset the PCI bus by setting bits 5-4 in PCI_MCFG */
450 ar2315_pci_reg_mask(apc, AR2315_PCI_MISC_CONFIG,
451 AR2315_PCIMISC_RST_MODE,
452 AR2315_PCIRST_LOW);
453 msleep(100);
454
455 /* Bring the PCI out of reset */
456 ar2315_pci_reg_mask(apc, AR2315_PCI_MISC_CONFIG,
457 AR2315_PCIMISC_RST_MODE,
458 AR2315_PCIRST_HIGH | AR2315_PCICACHE_DIS | 0x8);
459
460 ar2315_pci_reg_write(apc, AR2315_PCI_UNCACHE_CFG,
461 0x1E | /* 1GB uncached */
462 (1 << 5) | /* Enable uncached */
463 (0x2 << 30) /* Base: 0x80000000 */);
464 ar2315_pci_reg_read(apc, AR2315_PCI_UNCACHE_CFG);
465
466 msleep(500);
467
468 err = ar2315_pci_host_setup(apc);
469 if (err)
470 return err;
471
472 apc->domain = irq_domain_add_linear(NULL, AR2315_PCI_IRQ_COUNT,
473 &ar2315_pci_irq_domain_ops, apc);
474 if (!apc->domain) {
475 dev_err(dev, "failed to add IRQ domain\n");
476 return -ENOMEM;
477 }
478
479 ar2315_pci_irq_init(apc);
480
481 /* PCI controller does not support I/O ports */
482 apc->io_res.name = "AR2315 IO space";
483 apc->io_res.start = 0;
484 apc->io_res.end = 0;
485 apc->io_res.flags = IORESOURCE_IO;
486
487 apc->pci_ctrl.pci_ops = &ar2315_pci_ops;
488 apc->pci_ctrl.mem_resource = &apc->mem_res;
489 apc->pci_ctrl.io_resource = &apc->io_res;
490
491 register_pci_controller(&apc->pci_ctrl);
492
493 dev_info(dev, "register PCI controller\n");
494
495 return 0;
496 }
497
498 static struct platform_driver ar2315_pci_driver = {
499 .probe = ar2315_pci_probe,
500 .driver = {
501 .name = "ar2315-pci",
502 },
503 };
504
505 static int __init ar2315_pci_init(void)
506 {
507 return platform_driver_register(&ar2315_pci_driver);
508 }
509 arch_initcall(ar2315_pci_init);
510
511 int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
512 {
513 struct ar2315_pci_ctrl *apc = ar2315_pci_bus_to_apc(dev->bus);
514
515 return slot ? 0 : apc->irq_ext;
516 }
517
518 int pcibios_plat_dev_init(struct pci_dev *dev)
519 {
520 return 0;
521 }
522
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