diff options
Diffstat (limited to 'drivers/macintosh/via-cuda.c')
| -rw-r--r-- | drivers/macintosh/via-cuda.c | 155 |
1 files changed, 134 insertions, 21 deletions
diff --git a/drivers/macintosh/via-cuda.c b/drivers/macintosh/via-cuda.c index 57fb20dcb9dd..1a742bd9f612 100644 --- a/drivers/macintosh/via-cuda.c +++ b/drivers/macintosh/via-cuda.c @@ -1,10 +1,10 @@ /* - * Device driver for the via-cuda on Apple Powermacs. + * Device driver for the Cuda and Egret system controllers found on PowerMacs + * and 68k Macs. * - * The VIA (versatile interface adapter) interfaces to the CUDA, - * a 6805 microprocessor core which controls the ADB (Apple Desktop - * Bus) which connects to the keyboard and mouse. The CUDA also - * controls system power and the RTC (real time clock) chip. + * The Cuda or Egret is a 6805 microcontroller interfaced to the 6522 VIA. + * This MCU controls system power, Parameter RAM, Real Time Clock and the + * Apple Desktop Bus (ADB) that connects to the keyboard and mouse. * * Copyright (C) 1996 Paul Mackerras. */ @@ -50,10 +50,27 @@ static DEFINE_SPINLOCK(cuda_lock); #define IER (14*RS) /* Interrupt enable register */ #define ANH (15*RS) /* A-side data, no handshake */ -/* Bits in B data register: all active low */ -#define TREQ 0x08 /* Transfer request (input) */ -#define TACK 0x10 /* Transfer acknowledge (output) */ -#define TIP 0x20 /* Transfer in progress (output) */ +/* + * When the Cuda design replaced the Egret, some signal names and + * logic sense changed. They all serve the same purposes, however. + * + * VIA pin | Egret pin + * ----------------+------------------------------------------ + * PB3 (input) | Transceiver session (active low) + * PB4 (output) | VIA full (active high) + * PB5 (output) | System session (active high) + * + * VIA pin | Cuda pin + * ----------------+------------------------------------------ + * PB3 (input) | Transfer request (active low) + * PB4 (output) | Byte acknowledge (active low) + * PB5 (output) | Transfer in progress (active low) + */ + +/* Bits in Port B data register */ +#define TREQ 0x08 /* Transfer request */ +#define TACK 0x10 /* Transfer acknowledge */ +#define TIP 0x20 /* Transfer in progress */ /* Bits in ACR */ #define SR_CTRL 0x1c /* Shift register control bits */ @@ -65,6 +82,19 @@ static DEFINE_SPINLOCK(cuda_lock); #define IER_CLR 0 /* clear bits in IER */ #define SR_INT 0x04 /* Shift register full/empty */ +/* Duration of byte acknowledgement pulse (us) */ +#define EGRET_TACK_ASSERTED_DELAY 300 +#define EGRET_TACK_NEGATED_DELAY 400 + +/* Interval from interrupt to start of session (us) */ +#define EGRET_SESSION_DELAY 450 + +#ifdef CONFIG_PPC +#define mcu_is_egret false +#else +static bool mcu_is_egret; +#endif + static inline bool TREQ_asserted(u8 portb) { return !(portb & TREQ); @@ -72,12 +102,29 @@ static inline bool TREQ_asserted(u8 portb) static inline void assert_TIP(void) { - out_8(&via[B], in_8(&via[B]) & ~TIP); + if (mcu_is_egret) { + udelay(EGRET_SESSION_DELAY); + out_8(&via[B], in_8(&via[B]) | TIP); + } else + out_8(&via[B], in_8(&via[B]) & ~TIP); +} + +static inline void assert_TIP_and_TACK(void) +{ + if (mcu_is_egret) { + udelay(EGRET_SESSION_DELAY); + out_8(&via[B], in_8(&via[B]) | TIP | TACK); + } else + out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK)); } static inline void assert_TACK(void) { - out_8(&via[B], in_8(&via[B]) & ~TACK); + if (mcu_is_egret) { + udelay(EGRET_TACK_NEGATED_DELAY); + out_8(&via[B], in_8(&via[B]) | TACK); + } else + out_8(&via[B], in_8(&via[B]) & ~TACK); } static inline void toggle_TACK(void) @@ -87,12 +134,20 @@ static inline void toggle_TACK(void) static inline void negate_TACK(void) { - out_8(&via[B], in_8(&via[B]) | TACK); + if (mcu_is_egret) { + udelay(EGRET_TACK_ASSERTED_DELAY); + out_8(&via[B], in_8(&via[B]) & ~TACK); + } else + out_8(&via[B], in_8(&via[B]) | TACK); } static inline void negate_TIP_and_TACK(void) { - out_8(&via[B], in_8(&via[B]) | TIP | TACK); + if (mcu_is_egret) { + udelay(EGRET_TACK_ASSERTED_DELAY); + out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK)); + } else + out_8(&via[B], in_8(&via[B]) | TIP | TACK); } static enum cuda_state { @@ -155,6 +210,7 @@ int __init find_via_cuda(void) via = via1; cuda_state = idle; + mcu_is_egret = false; err = cuda_init_via(); if (err) { @@ -251,7 +307,7 @@ static int __init via_cuda_start(void) return -EAGAIN; } - pr_info("Macintosh CUDA driver v0.5 for Unified ADB.\n"); + pr_info("Macintosh Cuda and Egret driver.\n"); cuda_fully_inited = 1; return 0; @@ -276,6 +332,33 @@ cuda_probe(void) } #endif /* CONFIG_ADB */ +static int __init sync_egret(void) +{ + if (TREQ_asserted(in_8(&via[B]))) { + /* Complete the inbound transfer */ + assert_TIP_and_TACK(); + while (1) { + negate_TACK(); + mdelay(1); + (void)in_8(&via[SR]); + assert_TACK(); + if (!TREQ_asserted(in_8(&via[B]))) + break; + } + negate_TIP_and_TACK(); + } else if (in_8(&via[B]) & TIP) { + /* Terminate the outbound transfer */ + negate_TACK(); + assert_TACK(); + mdelay(1); + negate_TIP_and_TACK(); + } + /* Clear shift register interrupt */ + if (in_8(&via[IFR]) & SR_INT) + (void)in_8(&via[SR]); + return 0; +} + #define WAIT_FOR(cond, what) \ do { \ int x; \ @@ -291,10 +374,6 @@ cuda_probe(void) static int __init cuda_init_via(void) { - out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ); /* TACK & TIP out */ - negate_TIP_and_TACK(); - out_8(&via[ACR] ,(in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT); /* SR data in */ - (void)in_8(&via[SR]); /* clear any left-over data */ #ifdef CONFIG_PPC out_8(&via[IER], 0x7f); /* disable interrupts from VIA */ (void)in_8(&via[IER]); @@ -302,6 +381,15 @@ __init cuda_init_via(void) out_8(&via[IER], SR_INT); /* disable SR interrupt from VIA */ #endif + out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ); /* TACK & TIP out */ + out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT); /* SR data in */ + (void)in_8(&via[SR]); /* clear any left-over data */ + + if (mcu_is_egret) + return sync_egret(); + + negate_TIP_and_TACK(); + /* delay 4ms and then clear any pending interrupt */ mdelay(4); (void)in_8(&via[SR]); @@ -453,7 +541,10 @@ cuda_start(void) /* set the shift register to shift out and send a byte */ out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT); out_8(&via[SR], current_req->data[data_index++]); - assert_TIP(); + if (mcu_is_egret) + assert_TIP_and_TACK(); + else + assert_TIP(); cuda_state = sent_first_byte; } @@ -500,8 +591,9 @@ cuda_interrupt(int irq, void *arg) switch (cuda_state) { case idle: - /* CUDA has sent us the first byte of data - unsolicited */ + /* System controller has unsolicited data for us */ (void)in_8(&via[SR]); +idle_state: assert_TIP(); cuda_state = reading; reply_ptr = cuda_rbuf; @@ -509,7 +601,7 @@ cuda_interrupt(int irq, void *arg) break; case awaiting_reply: - /* CUDA has sent us the first byte of data of a reply */ + /* System controller has reply data for us */ (void)in_8(&via[SR]); assert_TIP(); cuda_state = reading; @@ -524,9 +616,14 @@ cuda_interrupt(int irq, void *arg) (void)in_8(&via[SR]); negate_TIP_and_TACK(); cuda_state = idle; + /* Egret does not raise an "aborted" interrupt */ + if (mcu_is_egret) + goto idle_state; } else { out_8(&via[SR], current_req->data[data_index++]); toggle_TACK(); + if (mcu_is_egret) + assert_TACK(); cuda_state = sending; } break; @@ -550,6 +647,8 @@ cuda_interrupt(int irq, void *arg) } else { out_8(&via[SR], req->data[data_index++]); toggle_TACK(); + if (mcu_is_egret) + assert_TACK(); } break; @@ -560,16 +659,24 @@ cuda_interrupt(int irq, void *arg) else *reply_ptr++ = in_8(&via[SR]); if (!TREQ_asserted(status)) { + if (mcu_is_egret) + assert_TACK(); /* that's all folks */ negate_TIP_and_TACK(); cuda_state = read_done; + /* Egret does not raise a "read done" interrupt */ + if (mcu_is_egret) + goto read_done_state; } else { toggle_TACK(); + if (mcu_is_egret) + negate_TACK(); } break; case read_done: (void)in_8(&via[SR]); +read_done_state: if (reading_reply) { req = current_req; req->reply_len = reply_ptr - req->reply; @@ -645,6 +752,12 @@ cuda_input(unsigned char *buf, int nb) #endif /* CONFIG_ADB */ break; + case TIMER_PACKET: + /* Egret sends these periodically. Might be useful as a 'heartbeat' + * to trigger a recovery for the VIA shift register errata. + */ + break; + default: print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1, buf, nb, false); |