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(data, ohci->registers + offset);
43}
44
45static 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 */
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, (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, (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, 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 */
177static 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 */
195static 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 */
206static 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 */
235static 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 */
257void __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 */
288static 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 */
296early_param("ohci1394_dma", setup_ohci1394_dma);
297