1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Apple Peripheral System Controller (PSC) 4 * 5 * The PSC is used on the AV Macs to control IO functions not handled 6 * by the VIAs (Ethernet, DSP, SCC). 7 * 8 * TO DO: 9 * 10 * Try to figure out what's going on in pIFR5 and pIFR6. There seem to be 11 * persisant interrupt conditions in those registers and I have no idea what 12 * they are. Granted it doesn't affect since we're not enabling any interrupts 13 * on those levels at the moment, but it would be nice to know. I have a feeling 14 * they aren't actually interrupt lines but data lines (to the DSP?) 15 */ 16 17 #include <linux/types.h> 18 #include <linux/kernel.h> 19 #include <linux/mm.h> 20 #include <linux/delay.h> 21 #include <linux/init.h> 22 #include <linux/irq.h> 23 24 #include <asm/traps.h> 25 #include <asm/macintosh.h> 26 #include <asm/macints.h> 27 #include <asm/mac_psc.h> 28 29 #include "mac.h" 30 31 #define DEBUG_PSC 32 33 volatile __u8 *psc; 34 EXPORT_SYMBOL_GPL(psc); 35 36 /* 37 * Debugging dump, used in various places to see what's going on. 38 */ 39 40 static void psc_debug_dump(void) 41 { 42 int i; 43 44 if (!psc) 45 return; 46 47 for (i = 0x30 ; i < 0x70 ; i += 0x10) { 48 printk(KERN_DEBUG "PSC #%d: IFR = 0x%02X IER = 0x%02X\n", 49 i >> 4, 50 (int) psc_read_byte(pIFRbase + i), 51 (int) psc_read_byte(pIERbase + i)); 52 } 53 } 54 55 /* 56 * Try to kill all DMA channels on the PSC. Not sure how this his 57 * supposed to work; this is code lifted from macmace.c and then 58 * expanded to cover what I think are the other 7 channels. 59 */ 60 61 static __init void psc_dma_die_die_die(void) 62 { 63 int i; 64 65 for (i = 0 ; i < 9 ; i++) { 66 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800); 67 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000); 68 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100); 69 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100); 70 } 71 } 72 73 /* 74 * Initialize the PSC. For now this just involves shutting down all 75 * interrupt sources using the IERs. 76 */ 77 78 void __init psc_init(void) 79 { 80 int i; 81 82 if (macintosh_config->ident != MAC_MODEL_C660 83 && macintosh_config->ident != MAC_MODEL_Q840) 84 { 85 psc = NULL; 86 return; 87 } 88 89 /* 90 * The PSC is always at the same spot, but using psc 91 * keeps things consistent with the psc_xxxx functions. 92 */ 93 94 psc = (void *) PSC_BASE; 95 96 pr_debug("PSC detected at %p\n", psc); 97 98 psc_dma_die_die_die(); 99 100 #ifdef DEBUG_PSC 101 psc_debug_dump(); 102 #endif 103 /* 104 * Mask and clear all possible interrupts 105 */ 106 107 for (i = 0x30 ; i < 0x70 ; i += 0x10) { 108 psc_write_byte(pIERbase + i, 0x0F); 109 psc_write_byte(pIFRbase + i, 0x0F); 110 } 111 } 112 113 /* 114 * PSC interrupt handler. It's a lot like the VIA interrupt handler. 115 */ 116 117 static void psc_irq(struct irq_desc *desc) 118 { 119 unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc); 120 unsigned int irq = irq_desc_get_irq(desc); 121 int pIFR = pIFRbase + offset; 122 int pIER = pIERbase + offset; 123 int irq_num; 124 unsigned char irq_bit, events; 125 126 events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF; 127 if (!events) 128 return; 129 130 irq_num = irq << 3; 131 irq_bit = 1; 132 do { 133 if (events & irq_bit) { 134 psc_write_byte(pIFR, irq_bit); 135 generic_handle_irq(irq_num); 136 } 137 irq_num++; 138 irq_bit <<= 1; 139 } while (events >= irq_bit); 140 } 141 142 /* 143 * Register the PSC interrupt dispatchers for autovector interrupts 3-6. 144 */ 145 146 void __init psc_register_interrupts(void) 147 { 148 irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30); 149 irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40); 150 irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50); 151 irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60); 152 } 153 154 void psc_irq_enable(int irq) { 155 int irq_src = IRQ_SRC(irq); 156 int irq_idx = IRQ_IDX(irq); 157 int pIER = pIERbase + (irq_src << 4); 158 159 psc_write_byte(pIER, (1 << irq_idx) | 0x80); 160 } 161 162 void psc_irq_disable(int irq) { 163 int irq_src = IRQ_SRC(irq); 164 int irq_idx = IRQ_IDX(irq); 165 int pIER = pIERbase + (irq_src << 4); 166 167 psc_write_byte(pIER, 1 << irq_idx); 168 } 169