target/linux/brcm2708/patches-3.18/0092-dwc_otg-introduce-fiq_fsm_spin-un-lock.patch

   1 From 424f79f35a94611f73182f19a7711174b756b052 Mon Sep 17 00:00:00 2001
   2 From: P33M <P33M@github.com>
   3 Date: Fri, 26 Sep 2014 11:32:09 +0100
   4 Subject: [PATCH 092/114] dwc_otg: introduce fiq_fsm_spin(un|)lock()
   5
   6 SMP safety for the FIQ relies on register read-modify write cycles being
   7 completed in the correct order. Several places in the DWC code modify
   8 registers also touched by the FIQ. Protect these by a bare-bones lock
   9 mechanism.
  10
  11 This also makes it possible to run the FIQ and IRQ handlers on different
  12 cores.
  13 ---
  14  .../usb/host/dwc_common_port/dwc_common_linux.c    |  6 ---
  15  drivers/usb/host/dwc_otg/dwc_otg_cil.c             | 10 -----
  16  drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c         | 46 +++++++++++++++++++++-
  17  drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h         | 16 +++++++-
  18  drivers/usb/host/dwc_otg/dwc_otg_hcd.c             | 23 ++++++++++-
  19  drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c        |  9 ++++-
  20  6 files changed, 88 insertions(+), 22 deletions(-)
  21
  22 --- a/drivers/usb/host/dwc_common_port/dwc_common_linux.c
  23 +++ b/drivers/usb/host/dwc_common_port/dwc_common_linux.c
  24 @@ -580,13 +580,7 @@ void DWC_WRITE_REG64(uint64_t volatile *
  25
  26  void DWC_MODIFY_REG32(uint32_t volatile *reg, uint32_t clear_mask, uint32_t set_mask)
  27  {
  28 -       unsigned long flags;
  29 -
  30 -       local_irq_save(flags);
  31 -       local_fiq_disable();
  32         writel((readl(reg) & ~clear_mask) | set_mask, reg);
  33 -       local_fiq_enable();
  34 -       local_irq_restore(flags);
  35  }
  36
  37  #if 0
  38 --- a/drivers/usb/host/dwc_otg/dwc_otg_cil.c
  39 +++ b/drivers/usb/host/dwc_otg/dwc_otg_cil.c
  40 @@ -2244,9 +2244,7 @@ void dwc_otg_core_host_init(dwc_otg_core
  41   */
  42  void dwc_otg_hc_init(dwc_otg_core_if_t * core_if, dwc_hc_t * hc)
  43  {
  44 -       uint32_t intr_enable;
  45         hcintmsk_data_t hc_intr_mask;
  46 -       gintmsk_data_t gintmsk = {.d32 = 0 };
  47         hcchar_data_t hcchar;
  48         hcsplt_data_t hcsplt;
  49
  50 @@ -2348,14 +2346,6 @@ void dwc_otg_hc_init(dwc_otg_core_if_t *
  51         }
  52         DWC_WRITE_REG32(&hc_regs->hcintmsk, hc_intr_mask.d32);
  53
  54 -       /* Enable the top level host channel interrupt. */
  55 -       intr_enable = (1 << hc_num);
  56 -       DWC_MODIFY_REG32(&host_if->host_global_regs->haintmsk, 0, intr_enable);
  57 -
  58 -       /* Make sure host channel interrupts are enabled. */
  59 -       gintmsk.b.hcintr = 1;
  60 -       DWC_MODIFY_REG32(&core_if->core_global_regs->gintmsk, 0, gintmsk.d32);
  61 -
  62         /*
  63          * Program the HCCHARn register with the endpoint characteristics for
  64          * the current transfer.
  65 --- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
  66 +++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.c
  67 @@ -75,6 +75,46 @@ void notrace _fiq_print(enum fiq_debug_l
  68  }
  69
  70  /**
  71 + * fiq_fsm_spin_lock() - ARMv6+ bare bones spinlock
  72 + * Must be called with local interrupts and FIQ disabled.
  73 + */
  74 +inline void fiq_fsm_spin_lock(fiq_lock_t *lock)
  75 +{
  76 +       unsigned long tmp;
  77 +       uint32_t newval;
  78 +       fiq_lock_t lockval;
  79 +       smp_mb__before_spinlock();
  80 +       /* Nested locking, yay. If we are on the same CPU as the fiq, then the disable
  81 +        * will be sufficient. If we are on a different CPU, then the lock protects us. */
  82 +       prefetchw(&lock->slock);
  83 +       asm volatile (
  84 +       "1:     ldrex   %0, [%3]\n"
  85 +       "       add     %1, %0, %4\n"
  86 +       "       strex   %2, %1, [%3]\n"
  87 +       "       teq     %2, #0\n"
  88 +       "       bne     1b"
  89 +       : "=&r" (lockval), "=&r" (newval), "=&r" (tmp)
  90 +       : "r" (&lock->slock), "I" (1 << 16)
  91 +       : "cc");
  92 +
  93 +       while (lockval.tickets.next != lockval.tickets.owner) {
  94 +               wfe();
  95 +               lockval.tickets.owner = ACCESS_ONCE(lock->tickets.owner);
  96 +       }
  97 +       smp_mb();
  98 +}
  99 +
 100 +/**
 101 + * fiq_fsm_spin_unlock() - ARMv6+ bare bones spinunlock
 102 + */
 103 +inline void fiq_fsm_spin_unlock(fiq_lock_t *lock)
 104 +{
 105 +       smp_mb();
 106 +       lock->tickets.owner++;
 107 +       dsb_sev();
 108 +}
 109 +
 110 +/**
 111   * fiq_fsm_restart_channel() - Poke channel enable bit for a split transaction
 112   * @channel: channel to re-enable
 113   */
 114 @@ -1142,6 +1182,7 @@ void notrace dwc_otg_fiq_fsm(struct fiq_
 115         gintsts_handled.d32 = 0;
 116         haint_handled.d32 = 0;
 117
 118 +       fiq_fsm_spin_lock(&state->lock);
 119         gintsts.d32 = FIQ_READ(state->dwc_regs_base + GINTSTS);
 120         gintmsk.d32 = FIQ_READ(state->dwc_regs_base + GINTMSK);
 121         gintsts.d32 &= gintmsk.d32;
 122 @@ -1231,7 +1272,7 @@ void notrace dwc_otg_fiq_fsm(struct fiq_
 123
 124         }
 125         state->fiq_done++;
 126 -       mb();
 127 +       fiq_fsm_spin_unlock(&state->lock);
 128  }
 129
 130
 131 @@ -1253,6 +1294,7 @@ void notrace dwc_otg_fiq_nop(struct fiq_
 132         gintmsk_data_t gintmsk;
 133         hfnum_data_t hfnum;
 134
 135 +       fiq_fsm_spin_lock(&state->lock);
 136         hfnum.d32 = FIQ_READ(state->dwc_regs_base + HFNUM);
 137         gintsts.d32 = FIQ_READ(state->dwc_regs_base + GINTSTS);
 138         gintmsk.d32 = FIQ_READ(state->dwc_regs_base + GINTMSK);
 139 @@ -1290,5 +1332,5 @@ void notrace dwc_otg_fiq_nop(struct fiq_
 140
 141         }
 142         state->fiq_done++;
 143 -       mb();
 144 +       fiq_fsm_spin_unlock(&state->lock);
 145  }
 146 --- a/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
 147 +++ b/drivers/usb/host/dwc_otg/dwc_otg_fiq_fsm.h
 148 @@ -120,7 +120,6 @@ typedef struct {
 149         volatile void* intstat;
 150  } mphi_regs_t;
 151
 152 -
 153  enum fiq_debug_level {
 154         FIQDBG_SCHED = (1 << 0),
 155         FIQDBG_INT   = (1 << 1),
 156 @@ -128,6 +127,16 @@ enum fiq_debug_level {
 157         FIQDBG_PORTHUB = (1 << 3),
 158  };
 159
 160 +typedef struct {
 161 +       union {
 162 +               uint32_t slock;
 163 +               struct _tickets {
 164 +                       uint16_t owner;
 165 +                       uint16_t next;
 166 +               } tickets;
 167 +       };
 168 +} fiq_lock_t;
 169 +
 170  struct fiq_state;
 171
 172  extern void _fiq_print (enum fiq_debug_level dbg_lvl, volatile struct fiq_state *state, char *fmt, ...);
 173 @@ -324,6 +333,7 @@ struct fiq_channel_state {
 174   * It contains top-level state information.
 175   */
 176  struct fiq_state {
 177 +       fiq_lock_t lock;
 178         mphi_regs_t mphi_regs;
 179         void *dwc_regs_base;
 180         dma_addr_t dma_base;
 181 @@ -342,6 +352,10 @@ struct fiq_state {
 182         struct fiq_channel_state channel[0];
 183  };
 184
 185 +extern void fiq_fsm_spin_lock(fiq_lock_t *lock);
 186 +
 187 +extern void fiq_fsm_spin_unlock(fiq_lock_t *lock);
 188 +
 189  extern int fiq_fsm_too_late(struct fiq_state *st, int n);
 190
 191  extern int fiq_fsm_tt_in_use(struct fiq_state *st, int num_channels, int n);
 192 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
 193 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
 194 @@ -1184,6 +1184,9 @@ static void assign_and_init_hc(dwc_otg_h
 195         dwc_otg_qtd_t *qtd;
 196         dwc_otg_hcd_urb_t *urb;
 197         void* ptr = NULL;
 198 +       uint32_t intr_enable;
 199 +       unsigned long flags;
 200 +       gintmsk_data_t gintmsk = { .d32 = 0, };
 201
 202         qtd = DWC_CIRCLEQ_FIRST(&qh->qtd_list);
 203
 204 @@ -1409,6 +1412,20 @@ static void assign_and_init_hc(dwc_otg_h
 205                 hc->desc_list_addr = qh->desc_list_dma;
 206
 207         dwc_otg_hc_init(hcd->core_if, hc);
 208 +
 209 +       local_irq_save(flags);
 210 +       local_fiq_disable();
 211 +       fiq_fsm_spin_lock(&hcd->fiq_state->lock);
 212 +       /* Enable the top level host channel interrupt. */
 213 +       intr_enable = (1 << hc->hc_num);
 214 +       DWC_MODIFY_REG32(&hcd->core_if->host_if->host_global_regs->haintmsk, 0, intr_enable);
 215 +
 216 +       /* Make sure host channel interrupts are enabled. */
 217 +       gintmsk.b.hcintr = 1;
 218 +       DWC_MODIFY_REG32(&hcd->core_if->core_global_regs->gintmsk, 0, gintmsk.d32);
 219 +       fiq_fsm_spin_unlock(&hcd->fiq_state->lock);
 220 +       local_fiq_enable();
 221 +       local_irq_restore(flags);
 222         hc->qh = qh;
 223  }
 224
 225 @@ -1659,6 +1676,7 @@ int fiq_fsm_queue_isoc_transaction(dwc_o
 226         fiq_print(FIQDBG_INT, hcd->fiq_state, "%08x", st->hcdma_copy.d32);
 227         hfnum.d32 = DWC_READ_REG32(&hcd->core_if->host_if->host_global_regs->hfnum);
 228         local_fiq_disable();
 229 +       fiq_fsm_spin_lock(&hcd->fiq_state->lock);
 230         DWC_WRITE_REG32(&hc_regs->hctsiz, st->hctsiz_copy.d32);
 231         DWC_WRITE_REG32(&hc_regs->hcsplt, st->hcsplt_copy.d32);
 232         DWC_WRITE_REG32(&hc_regs->hcdma, st->hcdma_copy.d32);
 233 @@ -1676,6 +1694,7 @@ int fiq_fsm_queue_isoc_transaction(dwc_o
 234         }
 235         mb();
 236         st->hcchar_copy.b.chen = 0;
 237 +       fiq_fsm_spin_unlock(&hcd->fiq_state->lock);
 238         local_fiq_enable();
 239         return 0;
 240  }
 241 @@ -1811,7 +1830,7 @@ int fiq_fsm_queue_split_transaction(dwc_
 242         DWC_WRITE_REG32(&hc_regs->hcintmsk, st->hcintmsk_copy.d32);
 243
 244         local_fiq_disable();
 245 -       mb();
 246 +       fiq_fsm_spin_lock(&hcd->fiq_state->lock);
 247
 248         if (hc->ep_type & 0x1) {
 249                 hfnum.d32 = DWC_READ_REG32(&hcd->core_if->host_if->host_global_regs->hfnum);
 250 @@ -1909,7 +1928,7 @@ int fiq_fsm_queue_split_transaction(dwc_
 251                 st->hcchar_copy.b.chen = 1;
 252                 DWC_WRITE_REG32(&hc_regs->hcchar, st->hcchar_copy.d32);
 253         }
 254 -       mb();
 255 +       fiq_fsm_spin_unlock(&hcd->fiq_state->lock);
 256         local_fiq_enable();
 257         return 0;
 258  }
 259 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
 260 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
 261 @@ -101,6 +101,7 @@ int32_t dwc_otg_hcd_handle_intr(dwc_otg_
 262         if (dwc_otg_is_host_mode(core_if)) {
 263                 if (fiq_enable) {
 264                         local_fiq_disable();
 265 +                       fiq_fsm_spin_lock(&dwc_otg_hcd->fiq_state->lock);
 266                         /* Pull in from the FIQ's disabled mask */
 267                         gintmsk.d32 = gintmsk.d32 | ~(dwc_otg_hcd->fiq_state->gintmsk_saved.d32);
 268                         dwc_otg_hcd->fiq_state->gintmsk_saved.d32 = ~0;
 269 @@ -116,8 +117,10 @@ int32_t dwc_otg_hcd_handle_intr(dwc_otg_
 270                 }
 271                 gintsts.d32 &= gintmsk.d32;
 272
 273 -               if (fiq_enable)
 274 +               if (fiq_enable) {
 275 +                       fiq_fsm_spin_unlock(&dwc_otg_hcd->fiq_state->lock);
 276                         local_fiq_enable();
 277 +               }
 278
 279                 if (!gintsts.d32) {
 280                         goto exit_handler_routine;
 281 @@ -200,6 +203,7 @@ exit_handler_routine:
 282                 gintmsk_data_t gintmsk_new;
 283                 haintmsk_data_t haintmsk_new;
 284                 local_fiq_disable();
 285 +               fiq_fsm_spin_lock(&dwc_otg_hcd->fiq_state->lock);
 286                 gintmsk_new.d32 = *(volatile uint32_t *)&dwc_otg_hcd->fiq_state->gintmsk_saved.d32;
 287                 if(fiq_fsm_enable)
 288                         haintmsk_new.d32 = *(volatile uint32_t *)&dwc_otg_hcd->fiq_state->haintmsk_saved.d32;
 289 @@ -222,6 +226,7 @@ exit_handler_routine:
 290                 haintmsk.d32 = DWC_READ_REG32(&core_if->host_if->host_global_regs->haintmsk);
 291                 /* Re-enable interrupts that the FIQ masked (first time round) */
 292                 FIQ_WRITE(dwc_otg_hcd->fiq_state->dwc_regs_base + GINTMSK, gintmsk.d32);
 293 +               fiq_fsm_spin_unlock(&dwc_otg_hcd->fiq_state->lock);
 294                 local_fiq_enable();
 295
 296                 if ((jiffies / HZ) > last_time) {
 297 @@ -633,8 +638,10 @@ int32_t dwc_otg_hcd_handle_hc_intr(dwc_o
 298         {
 299                 /* check the mask? */
 300                 local_fiq_disable();
 301 +               fiq_fsm_spin_lock(&dwc_otg_hcd->fiq_state->lock);
 302                 haint.b2.chint |= ~(dwc_otg_hcd->fiq_state->haintmsk_saved.b2.chint);
 303                 dwc_otg_hcd->fiq_state->haintmsk_saved.b2.chint = ~0;
 304 +               fiq_fsm_spin_unlock(&dwc_otg_hcd->fiq_state->lock);
 305                 local_fiq_enable();
 306         }
 307