drivers/firewire/init_ohci1394_dma.c

   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
  40 static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
  41 {
  42         writel(data, ohci->registers + offset);
  43 }
  44
  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 */
  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 */
  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) */
  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 */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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);