1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * init_ohci1394_dma.c - Initializes physical DMA on all OHCI 1394 controllers
4 *
5 * Copyright (C) 2006-2007 Bernhard Kaindl <bk@suse.de>
6 *
7 * Derived from drivers/ieee1394/ohci1394.c and arch/x86/kernel/early-quirks.c
8 * this file has functions to:
9 * - scan the PCI very early on boot for all OHCI 1394-compliant controllers
10 * - reset and initialize them and make them join the IEEE1394 bus and
11 * - enable physical DMA on them to allow remote debugging
12 *
13 * All code and data is marked as __init and __initdata, respective as
14 * during boot, all OHCI1394 controllers may be claimed by the firewire
15 * stack and at this point, this code should not touch them anymore.
16 *
17 * To use physical DMA after the initialization of the firewire stack,
18 * be sure that the stack enables it and (re-)attach after the bus reset
19 * which may be caused by the firewire stack initialization.
20 */
21
22 #include <linux/delay.h>
23 #include <linux/io.h>
24 #include <linux/kernel.h>
25 #include <linux/pci.h> /* for PCI defines */
26 #include <linux/string.h>
27
28 #include <asm/pci-direct.h> /* for direct PCI config space access */
29 #include <asm/fixmap.h>
30
31 #include <linux/init_ohci1394_dma.h>
32 #include "ohci.h"
33
34 int __initdata init_ohci1394_dma_early;
35
36 struct ohci {
37 void __iomem *registers;
38 };
39
reg_write(const struct ohci * ohci,int offset,u32 data)40 static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
41 {
42 writel(data, ohci->registers + offset);
43 }
44
reg_read(const struct ohci * ohci,int offset)45 static inline u32 reg_read(const struct ohci *ohci, int offset)
46 {
47 return readl(ohci->registers + offset);
48 }
49
50 #define OHCI_LOOP_COUNT 100 /* Number of loops for reg read waits */
51
52 /* Reads a PHY register of an OHCI-1394 controller */
get_phy_reg(struct ohci * ohci,u8 addr)53 static inline u8 __init get_phy_reg(struct ohci *ohci, u8 addr)
54 {
55 int i;
56 u32 r;
57
58 reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | 0x00008000);
59
60 for (i = 0; i < OHCI_LOOP_COUNT; i++) {
61 if (reg_read(ohci, OHCI1394_PhyControl) & 0x80000000)
62 break;
63 mdelay(1);
64 }
65 r = reg_read(ohci, OHCI1394_PhyControl);
66
67 return (r & 0x00ff0000) >> 16;
68 }
69
70 /* Writes to a PHY register of an OHCI-1394 controller */
set_phy_reg(struct ohci * ohci,u8 addr,u8 data)71 static inline void __init set_phy_reg(struct ohci *ohci, u8 addr, u8 data)
72 {
73 int i;
74
75 reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | data | 0x00004000);
76
77 for (i = 0; i < OHCI_LOOP_COUNT; i++) {
78 if (!(reg_read(ohci, OHCI1394_PhyControl) & 0x00004000))
79 break;
80 mdelay(1);
81 }
82 }
83
84 /* Resets an OHCI-1394 controller (for sane state before initialization) */
init_ohci1394_soft_reset(struct ohci * ohci)85 static inline void __init init_ohci1394_soft_reset(struct ohci *ohci)
86 {
87 int i;
88
89 reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_softReset);
90
91 for (i = 0; i < OHCI_LOOP_COUNT; i++) {
92 if (!(reg_read(ohci, OHCI1394_HCControlSet)
93 & OHCI1394_HCControl_softReset))
94 break;
95 mdelay(1);
96 }
97 }
98
99 #define OHCI1394_MAX_AT_REQ_RETRIES 0xf
100 #define OHCI1394_MAX_AT_RESP_RETRIES 0x2
101 #define OHCI1394_MAX_PHYS_RESP_RETRIES 0x8
102
103 /* Basic OHCI-1394 register and port inititalization */
init_ohci1394_initialize(struct ohci * ohci)104 static inline void __init init_ohci1394_initialize(struct ohci *ohci)
105 {
106 u32 bus_options;
107 int num_ports, i;
108
109 /* Put some defaults to these undefined bus options */
110 bus_options = reg_read(ohci, OHCI1394_BusOptions);
111 bus_options |= 0x60000000; /* Enable CMC and ISC */
112 bus_options &= ~0x00ff0000; /* XXX: Set cyc_clk_acc to zero for now */
113 bus_options &= ~0x18000000; /* Disable PMC and BMC */
114 reg_write(ohci, OHCI1394_BusOptions, bus_options);
115
116 /* Set the bus number */
117 reg_write(ohci, OHCI1394_NodeID, 0x0000ffc0);
118
119 /* Enable posted writes */
120 reg_write(ohci, OHCI1394_HCControlSet,
121 OHCI1394_HCControl_postedWriteEnable);
122
123 /* Clear link control register */
124 reg_write(ohci, OHCI1394_LinkControlClear, 0xffffffff);
125
126 /* enable phys */
127 reg_write(ohci, OHCI1394_LinkControlSet,
128 OHCI1394_LinkControl_rcvPhyPkt);
129
130 /* Don't accept phy packets into AR request context */
131 reg_write(ohci, OHCI1394_LinkControlClear, 0x00000400);
132
133 /* Clear the Isochonouys interrupt masks */
134 reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 0xffffffff);
135 reg_write(ohci, OHCI1394_IsoRecvIntEventClear, 0xffffffff);
136 reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, 0xffffffff);
137 reg_write(ohci, OHCI1394_IsoXmitIntEventClear, 0xffffffff);
138
139 /* Accept asynchronous transfer requests from all nodes for now */
140 reg_write(ohci, OHCI1394_AsReqFilterHiSet, 0x80000000);
141
142 /* Specify asynchronous transfer retries */
143 reg_write(ohci, OHCI1394_ATRetries,
144 OHCI1394_MAX_AT_REQ_RETRIES |
145 (OHCI1394_MAX_AT_RESP_RETRIES<<4) |
146 (OHCI1394_MAX_PHYS_RESP_RETRIES<<8));
147
148 /* We don't want hardware swapping */
149 reg_write(ohci, OHCI1394_HCControlClear,
150 OHCI1394_HCControl_noByteSwapData);
151
152 /* Enable link */
153 reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_linkEnable);
154
155 /* If anything is connected to a port, make sure it is enabled */
156 num_ports = get_phy_reg(ohci, 2) & 0xf;
157 for (i = 0; i < num_ports; i++) {
158 unsigned int status;
159
160 set_phy_reg(ohci, 7, i);
161 status = get_phy_reg(ohci, 8);
162
163 if (status & 0x20)
164 set_phy_reg(ohci, 8, status & ~1);
165 }
166 }
167
168 /**
169 * init_ohci1394_wait_for_busresets - wait until bus resets are completed
170 *
171 * OHCI1394 initialization itself and any device going on- or offline
172 * and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
173 * specifies that physical DMA is disabled on each bus reset and it
174 * has to be enabled after each bus reset when needed. We resort
175 * to polling here because on early boot, we have no interrupts.
176 */
init_ohci1394_wait_for_busresets(struct ohci * ohci)177 static inline void __init init_ohci1394_wait_for_busresets(struct ohci *ohci)
178 {
179 int i, events;
180
181 for (i = 0; i < 9; i++) {
182 mdelay(200);
183 events = reg_read(ohci, OHCI1394_IntEventSet);
184 if (events & OHCI1394_busReset)
185 reg_write(ohci, OHCI1394_IntEventClear,
186 OHCI1394_busReset);
187 }
188 }
189
190 /**
191 * init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
192 * This enables remote DMA access over IEEE1394 from every host for the low
193 * 4GB of address space. DMA accesses above 4GB are not available currently.
194 */
init_ohci1394_enable_physical_dma(struct ohci * ohci)195 static inline void __init init_ohci1394_enable_physical_dma(struct ohci *ohci)
196 {
197 reg_write(ohci, OHCI1394_PhyReqFilterHiSet, 0xffffffff);
198 reg_write(ohci, OHCI1394_PhyReqFilterLoSet, 0xffffffff);
199 reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
200 }
201
202 /**
203 * init_ohci1394_reset_and_init_dma - init controller and enable DMA
204 * This initializes the given controller and enables physical DMA engine in it.
205 */
init_ohci1394_reset_and_init_dma(struct ohci * ohci)206 static inline void __init init_ohci1394_reset_and_init_dma(struct ohci *ohci)
207 {
208 /* Start off with a soft reset, clears everything to a sane state. */
209 init_ohci1394_soft_reset(ohci);
210
211 /* Accessing some registers without LPS enabled may cause lock up */
212 reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_LPS);
213
214 /* Disable and clear interrupts */
215 reg_write(ohci, OHCI1394_IntEventClear, 0xffffffff);
216 reg_write(ohci, OHCI1394_IntMaskClear, 0xffffffff);
217
218 mdelay(50); /* Wait 50msec to make sure we have full link enabled */
219
220 init_ohci1394_initialize(ohci);
221 /*
222 * The initialization causes at least one IEEE1394 bus reset. Enabling
223 * physical DMA only works *after* *all* bus resets have calmed down:
224 */
225 init_ohci1394_wait_for_busresets(ohci);
226
227 /* We had to wait and do this now if we want to debug early problems */
228 init_ohci1394_enable_physical_dma(ohci);
229 }
230
231 /**
232 * init_ohci1394_controller - Map the registers of the controller and init DMA
233 * This maps the registers of the specified controller and initializes it
234 */
init_ohci1394_controller(int num,int slot,int func)235 static inline void __init init_ohci1394_controller(int num, int slot, int func)
236 {
237 unsigned long ohci_base;
238 struct ohci ohci;
239
240 printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"
241 " at %02x:%02x.%x\n", num, slot, func);
242
243 ohci_base = read_pci_config(num, slot, func, PCI_BASE_ADDRESS_0+(0<<2))
244 & PCI_BASE_ADDRESS_MEM_MASK;
245
246 set_fixmap_nocache(FIX_OHCI1394_BASE, ohci_base);
247
248 ohci.registers = (void __iomem *)fix_to_virt(FIX_OHCI1394_BASE);
249
250 init_ohci1394_reset_and_init_dma(&ohci);
251 }
252
253 /**
254 * init_ohci1394_dma_on_all_controllers - scan for OHCI1394 controllers and init DMA on them
255 * Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
256 */
init_ohci1394_dma_on_all_controllers(void)257 void __init init_ohci1394_dma_on_all_controllers(void)
258 {
259 int num, slot, func;
260 u32 class;
261
262 if (!early_pci_allowed())
263 return;
264
265 /* Poor man's PCI discovery, the only thing we can do at early boot */
266 for (num = 0; num < 32; num++) {
267 for (slot = 0; slot < 32; slot++) {
268 for (func = 0; func < 8; func++) {
269 class = read_pci_config(num, slot, func,
270 PCI_CLASS_REVISION);
271 if (class == 0xffffffff)
272 continue; /* No device at this func */
273
274 if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
275 continue; /* Not an OHCI-1394 device */
276
277 init_ohci1394_controller(num, slot, func);
278 break; /* Assume one controller per device */
279 }
280 }
281 }
282 printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI DMA\n");
283 }
284
285 /**
286 * setup_ohci1394_dma - enables early OHCI1394 DMA initialization
287 */
setup_ohci1394_dma(char * opt)288 static int __init setup_ohci1394_dma(char *opt)
289 {
290 if (!strcmp(opt, "early"))
291 init_ohci1394_dma_early = 1;
292 return 0;
293 }
294
295 /* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */
296 early_param("ohci1394_dma", setup_ohci1394_dma);
297