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
34int __initdata init_ohci1394_dma_early;
35
36struct ohci {
37 void __iomem *registers;
38};
39
40static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
41{
42 writel(val: data, addr: ohci->registers + offset);
43}
44
45static inline u32 reg_read(const struct ohci *ohci, int offset)
46{
47 return readl(addr: 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 */
53static 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, data: (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 */
71static inline void __init set_phy_reg(struct ohci *ohci, u8 addr, u8 data)
72{
73 int i;
74
75 reg_write(ohci, OHCI1394_PhyControl, data: (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) */
85static 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 */
104static 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, data: bus_options);
115
116 /* Set the bus number */
117 reg_write(ohci, OHCI1394_NodeID, data: 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, data: 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, data: 0x00000400);
132
133 /* Clear the Isochonouys interrupt masks */
134 reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, data: 0xffffffff);
135 reg_write(ohci, OHCI1394_IsoRecvIntEventClear, data: 0xffffffff);
136 reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, data: 0xffffffff);
137 reg_write(ohci, OHCI1394_IsoXmitIntEventClear, data: 0xffffffff);
138
139 /* Accept asynchronous transfer requests from all nodes for now */
140 reg_write(ohci, OHCI1394_AsReqFilterHiSet, data: 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, addr: 2) & 0xf;
157 for (i = 0; i < num_ports; i++) {
158 unsigned int status;
159
160 set_phy_reg(ohci, addr: 7, data: i);
161 status = get_phy_reg(ohci, addr: 8);
162
163 if (status & 0x20)
164 set_phy_reg(ohci, addr: 8, data: status & ~1);
165 }
166}
167
168/**
169 * init_ohci1394_wait_for_busresets - wait until bus resets are completed
170 * @ohci: Pointer to the OHCI-1394 controller structure
171 *
172 * OHCI1394 initialization itself and any device going on- or offline
173 * and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
174 * specifies that physical DMA is disabled on each bus reset and it
175 * has to be enabled after each bus reset when needed. We resort
176 * to polling here because on early boot, we have no interrupts.
177 */
178static inline void __init init_ohci1394_wait_for_busresets(struct ohci *ohci)
179{
180 int i, events;
181
182 for (i = 0; i < 9; i++) {
183 mdelay(200);
184 events = reg_read(ohci, OHCI1394_IntEventSet);
185 if (events & OHCI1394_busReset)
186 reg_write(ohci, OHCI1394_IntEventClear,
187 OHCI1394_busReset);
188 }
189}
190
191/**
192 * init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
193 * @ohci: Pointer to the OHCI-1394 controller structure
194 *
195 * This enables remote DMA access over IEEE1394 from every host for the low
196 * 4GB of address space. DMA accesses above 4GB are not available currently.
197 */
198static inline void __init init_ohci1394_enable_physical_dma(struct ohci *ohci)
199{
200 reg_write(ohci, OHCI1394_PhyReqFilterHiSet, data: 0xffffffff);
201 reg_write(ohci, OHCI1394_PhyReqFilterLoSet, data: 0xffffffff);
202 reg_write(ohci, OHCI1394_PhyUpperBound, data: 0xffff0000);
203}
204
205/**
206 * init_ohci1394_reset_and_init_dma - init controller and enable DMA
207 * @ohci: Pointer to the OHCI-1394 controller structure
208 *
209 * This initializes the given controller and enables physical DMA engine in it.
210 */
211static inline void __init init_ohci1394_reset_and_init_dma(struct ohci *ohci)
212{
213 /* Start off with a soft reset, clears everything to a sane state. */
214 init_ohci1394_soft_reset(ohci);
215
216 /* Accessing some registers without LPS enabled may cause lock up */
217 reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_LPS);
218
219 /* Disable and clear interrupts */
220 reg_write(ohci, OHCI1394_IntEventClear, data: 0xffffffff);
221 reg_write(ohci, OHCI1394_IntMaskClear, data: 0xffffffff);
222
223 mdelay(50); /* Wait 50msec to make sure we have full link enabled */
224
225 init_ohci1394_initialize(ohci);
226 /*
227 * The initialization causes at least one IEEE1394 bus reset. Enabling
228 * physical DMA only works *after* *all* bus resets have calmed down:
229 */
230 init_ohci1394_wait_for_busresets(ohci);
231
232 /* We had to wait and do this now if we want to debug early problems */
233 init_ohci1394_enable_physical_dma(ohci);
234}
235
236/**
237 * init_ohci1394_controller - Map the registers of the controller and init DMA
238 * @num: PCI bus number
239 * @slot: PCI device number
240 * @func: PCI function number
241 *
242 * This maps the registers of the specified controller and initializes it
243 */
244static inline void __init init_ohci1394_controller(int num, int slot, int func)
245{
246 unsigned long ohci_base;
247 struct ohci ohci;
248
249 printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"
250 " at %02x:%02x.%x\n", num, slot, func);
251
252 ohci_base = read_pci_config(bus: num, slot, func, PCI_BASE_ADDRESS_0+(0<<2))
253 & PCI_BASE_ADDRESS_MEM_MASK;
254
255 set_fixmap_nocache(FIX_OHCI1394_BASE, ohci_base);
256
257 ohci.registers = (void __iomem *)fix_to_virt(idx: FIX_OHCI1394_BASE);
258
259 init_ohci1394_reset_and_init_dma(ohci: &ohci);
260}
261
262/**
263 * init_ohci1394_dma_on_all_controllers - scan for OHCI1394 controllers and init DMA on them
264 * Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
265 */
266void __init init_ohci1394_dma_on_all_controllers(void)
267{
268 int num, slot, func;
269 u32 class;
270
271 if (!early_pci_allowed())
272 return;
273
274 /* Poor man's PCI discovery, the only thing we can do at early boot */
275 for (num = 0; num < 32; num++) {
276 for (slot = 0; slot < 32; slot++) {
277 for (func = 0; func < 8; func++) {
278 class = read_pci_config(bus: num, slot, func,
279 PCI_CLASS_REVISION);
280 if (class == 0xffffffff)
281 continue; /* No device at this func */
282
283 if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
284 continue; /* Not an OHCI-1394 device */
285
286 init_ohci1394_controller(num, slot, func);
287 break; /* Assume one controller per device */
288 }
289 }
290 }
291 printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI DMA\n");
292}
293
294/**
295 * setup_ohci1394_dma - enables early OHCI1394 DMA initialization
296 * @opt: Kernel command line parameter string
297 */
298static int __init setup_ohci1394_dma(char *opt)
299{
300 if (!strcmp(opt, "early"))
301 init_ohci1394_dma_early = 1;
302 return 0;
303}
304
305/* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */
306early_param("ohci1394_dma", setup_ohci1394_dma);
307

source code of linux/drivers/firewire/init_ohci1394_dma.c