/*
   *	Apple Peripheral System Controller (PSC)
   *
   *	The PSC is used on the AV Macs to control IO functions not handled
   *	by the VIAs (Ethernet, DSP, SCC).
   *
   * TO DO:
   *
   * Try to figure out what's going on in pIFR5 and pIFR6. There seem to be
   * persisant interrupt conditions in those registers and I have no idea what
   * they are. Granted it doesn't affect since we're not enabling any interrupts
   * on those levels at the moment, but it would be nice to know. I have a feeling
   * they aren't actually interrupt lines but data lines (to the DSP?)
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/mm.h>
  #include <linux/delay.h>
  #include <linux/init.h>
  #include <linux/irq.h>
  
  #include <asm/traps.h>
  #include <asm/macintosh.h>
  #include <asm/macints.h>
  #include <asm/mac_psc.h>
  
  #define DEBUG_PSC
  
  int psc_present;
  volatile __u8 *psc;
  
  /*
   * Debugging dump, used in various places to see what's going on.
   */
  
  static void psc_debug_dump(void)
  {
  	int	i;
  
  	if (!psc_present) return;
  	for (i = 0x30 ; i < 0x70 ; i += 0x10) {
  		printk("PSC #%d:  IFR = 0x%02X IER = 0x%02X
  ",
  			i >> 4,
  			(int) psc_read_byte(pIFRbase + i),
  			(int) psc_read_byte(pIERbase + i));
  	}
  }
  
  /*
   * Try to kill all DMA channels on the PSC. Not sure how this his
   * supposed to work; this is code lifted from macmace.c and then
   * expanded to cover what I think are the other 7 channels.
   */
  
  static __init void psc_dma_die_die_die(void)
  {
  	int i;
  
  	printk("Killing all PSC DMA channels...");
  	for (i = 0 ; i < 9 ; i++) {
  		psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
  		psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
  		psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
  		psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
  	}
  	printk("done!
  ");
  }
  
  /*
   * Initialize the PSC. For now this just involves shutting down all
   * interrupt sources using the IERs.
   */
  
  void __init psc_init(void)
  {
  	int i;
  
  	if (macintosh_config->ident != MAC_MODEL_C660
  	 && macintosh_config->ident != MAC_MODEL_Q840)
  	{
  		psc = NULL;
  		psc_present = 0;
  		return;
  	}
  
  	/*
  	 * The PSC is always at the same spot, but using psc
  	 * keeps things consistent with the psc_xxxx functions.
  	 */
  
  	psc = (void *) PSC_BASE;
  	psc_present = 1;
  
  	printk("PSC detected at %p
  ", psc);
  
  	psc_dma_die_die_die();
  
  #ifdef DEBUG_PSC
  	psc_debug_dump();
  #endif
  	/*
  	 * Mask and clear all possible interrupts
  	 */
  
  	for (i = 0x30 ; i < 0x70 ; i += 0x10) {
  		psc_write_byte(pIERbase + i, 0x0F);
  		psc_write_byte(pIFRbase + i, 0x0F);
  	}
  }
  
  /*
   * PSC interrupt handler. It's a lot like the VIA interrupt handler.
   */
  
  static void psc_irq(unsigned int irq, struct irq_desc *desc)
  {
  	unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
  	int pIFR	= pIFRbase + offset;
  	int pIER	= pIERbase + offset;
  	int irq_num;
  	unsigned char irq_bit, events;
  
  #ifdef DEBUG_IRQS
  	printk("psc_irq: irq %u pIFR = 0x%02X pIER = 0x%02X
  ",
  		irq, (int) psc_read_byte(pIFR), (int) psc_read_byte(pIER));
  #endif
  
  	events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
  	if (!events)
  		return;
  
  	irq_num = irq << 3;
  	irq_bit = 1;
  	do {
  		if (events & irq_bit) {
  			psc_write_byte(pIFR, irq_bit);
  			generic_handle_irq(irq_num);
  		}
  		irq_num++;
  		irq_bit <<= 1;
  	} while (events >= irq_bit);
  }
  
  /*
   * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
   */
  
  void __init psc_register_interrupts(void)
  {
  	irq_set_chained_handler(IRQ_AUTO_3, psc_irq);
  	irq_set_handler_data(IRQ_AUTO_3, (void *)0x30);
  	irq_set_chained_handler(IRQ_AUTO_4, psc_irq);
  	irq_set_handler_data(IRQ_AUTO_4, (void *)0x40);
  	irq_set_chained_handler(IRQ_AUTO_5, psc_irq);
  	irq_set_handler_data(IRQ_AUTO_5, (void *)0x50);
  	irq_set_chained_handler(IRQ_AUTO_6, psc_irq);
  	irq_set_handler_data(IRQ_AUTO_6, (void *)0x60);
  }
  
  void psc_irq_enable(int irq) {
  	int irq_src	= IRQ_SRC(irq);
  	int irq_idx	= IRQ_IDX(irq);
  	int pIER	= pIERbase + (irq_src << 4);
  
  #ifdef DEBUG_IRQUSE
  	printk("psc_irq_enable(%d)
  ", irq);
  #endif
  	psc_write_byte(pIER, (1 << irq_idx) | 0x80);
  }
  
  void psc_irq_disable(int irq) {
  	int irq_src	= IRQ_SRC(irq);
  	int irq_idx	= IRQ_IDX(irq);
  	int pIER	= pIERbase + (irq_src << 4);
  
  #ifdef DEBUG_IRQUSE
  	printk("psc_irq_disable(%d)
  ", irq);
  #endif
  	psc_write_byte(pIER, 1 << irq_idx);
  }