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 #define DEBUG_PSC 30 31 volatile __u8 *psc; 32 EXPORT_SYMBOL_GPL(psc); 33 34 /* 35 * Debugging dump, used in various places to see what's going on. 36 */ 37 38 static void psc_debug_dump(void) 39 { 40 int i; 41 42 if (!psc) 43 return; 44 45 for (i = 0x30 ; i < 0x70 ; i += 0x10) { 46 printk(KERN_DEBUG "PSC #%d: IFR = 0x%02X IER = 0x%02X\n", 47 i >> 4, 48 (int) psc_read_byte(pIFRbase + i), 49 (int) psc_read_byte(pIERbase + i)); 50 } 51 } 52 53 /* 54 * Try to kill all DMA channels on the PSC. Not sure how this his 55 * supposed to work; this is code lifted from macmace.c and then 56 * expanded to cover what I think are the other 7 channels. 57 */ 58 59 static __init void psc_dma_die_die_die(void) 60 { 61 int i; 62 63 for (i = 0 ; i < 9 ; i++) { 64 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800); 65 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000); 66 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100); 67 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100); 68 } 69 } 70 71 /* 72 * Initialize the PSC. For now this just involves shutting down all 73 * interrupt sources using the IERs. 74 */ 75 76 void __init psc_init(void) 77 { 78 int i; 79 80 if (macintosh_config->ident != MAC_MODEL_C660 81 && macintosh_config->ident != MAC_MODEL_Q840) 82 { 83 psc = NULL; 84 return; 85 } 86 87 /* 88 * The PSC is always at the same spot, but using psc 89 * keeps things consistent with the psc_xxxx functions. 90 */ 91 92 psc = (void *) PSC_BASE; 93 94 pr_debug("PSC detected at %p\n", psc); 95 96 psc_dma_die_die_die(); 97 98 #ifdef DEBUG_PSC 99 psc_debug_dump(); 100 #endif 101 /* 102 * Mask and clear all possible interrupts 103 */ 104 105 for (i = 0x30 ; i < 0x70 ; i += 0x10) { 106 psc_write_byte(pIERbase + i, 0x0F); 107 psc_write_byte(pIFRbase + i, 0x0F); 108 } 109 } 110 111 /* 112 * PSC interrupt handler. It's a lot like the VIA interrupt handler. 113 */ 114 115 static void psc_irq(struct irq_desc *desc) 116 { 117 unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc); 118 unsigned int irq = irq_desc_get_irq(desc); 119 int pIFR = pIFRbase + offset; 120 int pIER = pIERbase + offset; 121 int irq_num; 122 unsigned char irq_bit, events; 123 124 events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF; 125 if (!events) 126 return; 127 128 irq_num = irq << 3; 129 irq_bit = 1; 130 do { 131 if (events & irq_bit) { 132 psc_write_byte(pIFR, irq_bit); 133 generic_handle_irq(irq_num); 134 } 135 irq_num++; 136 irq_bit <<= 1; 137 } while (events >= irq_bit); 138 } 139 140 /* 141 * Register the PSC interrupt dispatchers for autovector interrupts 3-6. 142 */ 143 144 void __init psc_register_interrupts(void) 145 { 146 irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30); 147 irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40); 148 irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50); 149 irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60); 150 } 151 152 void psc_irq_enable(int irq) { 153 int irq_src = IRQ_SRC(irq); 154 int irq_idx = IRQ_IDX(irq); 155 int pIER = pIERbase + (irq_src << 4); 156 157 psc_write_byte(pIER, (1 << irq_idx) | 0x80); 158 } 159 160 void psc_irq_disable(int irq) { 161 int irq_src = IRQ_SRC(irq); 162 int irq_idx = IRQ_IDX(irq); 163 int pIER = pIERbase + (irq_src << 4); 164 165 psc_write_byte(pIER, 1 << irq_idx); 166 } 167