1 /* 2 * Operating System Services (OSS) chip handling 3 * Written by Joshua M. Thompson (funaho@jurai.org) 4 * 5 * 6 * This chip is used in the IIfx in place of VIA #2. It acts like a fancy 7 * VIA chip with prorammable interrupt levels. 8 * 9 * 990502 (jmt) - Major rewrite for new interrupt architecture as well as some 10 * recent insights into OSS operational details. 11 * 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped 12 * to mostly match the A/UX interrupt scheme supported on the 13 * VIA side. Also added support for enabling the ISM irq again 14 * since we now have a functional IOP manager. 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/macintosh.h> 25 #include <asm/macints.h> 26 #include <asm/mac_via.h> 27 #include <asm/mac_oss.h> 28 29 int oss_present; 30 volatile struct mac_oss *oss; 31 32 /* 33 * Initialize the OSS 34 * 35 * The OSS "detection" code is actually in via_init() which is always called 36 * before us. Thus we can count on oss_present being valid on entry. 37 */ 38 39 void __init oss_init(void) 40 { 41 int i; 42 43 if (!oss_present) return; 44 45 oss = (struct mac_oss *) OSS_BASE; 46 47 /* Disable all interrupts. Unlike a VIA it looks like we */ 48 /* do this by setting the source's interrupt level to zero. */ 49 50 for (i = 0; i <= OSS_NUM_SOURCES; i++) { 51 oss->irq_level[i] = 0; 52 } 53 } 54 55 /* 56 * Initialize OSS for Nubus access 57 */ 58 59 void __init oss_nubus_init(void) 60 { 61 } 62 63 /* 64 * Handle miscellaneous OSS interrupts. 65 */ 66 67 static void oss_irq(unsigned int irq, struct irq_desc *desc) 68 { 69 int events = oss->irq_pending & 70 (OSS_IP_IOPSCC | OSS_IP_SCSI | OSS_IP_IOPISM); 71 72 #ifdef DEBUG_IRQS 73 if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) { 74 printk("oss_irq: irq %u events = 0x%04X\n", irq, 75 (int) oss->irq_pending); 76 } 77 #endif 78 79 if (events & OSS_IP_IOPSCC) { 80 oss->irq_pending &= ~OSS_IP_IOPSCC; 81 generic_handle_irq(IRQ_MAC_SCC); 82 } 83 84 if (events & OSS_IP_SCSI) { 85 oss->irq_pending &= ~OSS_IP_SCSI; 86 generic_handle_irq(IRQ_MAC_SCSI); 87 } 88 89 if (events & OSS_IP_IOPISM) { 90 oss->irq_pending &= ~OSS_IP_IOPISM; 91 generic_handle_irq(IRQ_MAC_ADB); 92 } 93 } 94 95 /* 96 * Nubus IRQ handler, OSS style 97 * 98 * Unlike the VIA/RBV this is on its own autovector interrupt level. 99 */ 100 101 static void oss_nubus_irq(unsigned int irq, struct irq_desc *desc) 102 { 103 int events, irq_bit, i; 104 105 events = oss->irq_pending & OSS_IP_NUBUS; 106 if (!events) 107 return; 108 109 #ifdef DEBUG_NUBUS_INT 110 if (console_loglevel > 7) { 111 printk("oss_nubus_irq: events = 0x%04X\n", events); 112 } 113 #endif 114 /* There are only six slots on the OSS, not seven */ 115 116 i = 6; 117 irq_bit = 0x40; 118 do { 119 --i; 120 irq_bit >>= 1; 121 if (events & irq_bit) { 122 oss->irq_pending &= ~irq_bit; 123 generic_handle_irq(NUBUS_SOURCE_BASE + i); 124 } 125 } while(events & (irq_bit - 1)); 126 } 127 128 /* 129 * Register the OSS and NuBus interrupt dispatchers. 130 * 131 * This IRQ mapping is laid out with two things in mind: first, we try to keep 132 * things on their own levels to avoid having to do double-dispatches. Second, 133 * the levels match as closely as possible the alternate IRQ mapping mode (aka 134 * "A/UX mode") available on some VIA machines. 135 */ 136 137 #define OSS_IRQLEV_IOPISM IRQ_AUTO_1 138 #define OSS_IRQLEV_SCSI IRQ_AUTO_2 139 #define OSS_IRQLEV_NUBUS IRQ_AUTO_3 140 #define OSS_IRQLEV_IOPSCC IRQ_AUTO_4 141 #define OSS_IRQLEV_VIA1 IRQ_AUTO_6 142 143 void __init oss_register_interrupts(void) 144 { 145 irq_set_chained_handler(OSS_IRQLEV_IOPISM, oss_irq); 146 irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_irq); 147 irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq); 148 irq_set_chained_handler(OSS_IRQLEV_IOPSCC, oss_irq); 149 irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq); 150 151 /* OSS_VIA1 gets enabled here because it has no machspec interrupt. */ 152 oss->irq_level[OSS_VIA1] = IRQ_AUTO_6; 153 } 154 155 /* 156 * Enable an OSS interrupt 157 * 158 * It looks messy but it's rather straightforward. The switch() statement 159 * just maps the machspec interrupt numbers to the right OSS interrupt 160 * source (if the OSS handles that interrupt) and then sets the interrupt 161 * level for that source to nonzero, thus enabling the interrupt. 162 */ 163 164 void oss_irq_enable(int irq) { 165 #ifdef DEBUG_IRQUSE 166 printk("oss_irq_enable(%d)\n", irq); 167 #endif 168 switch(irq) { 169 case IRQ_MAC_SCC: 170 oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC; 171 return; 172 case IRQ_MAC_ADB: 173 oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM; 174 return; 175 case IRQ_MAC_SCSI: 176 oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI; 177 return; 178 case IRQ_NUBUS_9: 179 case IRQ_NUBUS_A: 180 case IRQ_NUBUS_B: 181 case IRQ_NUBUS_C: 182 case IRQ_NUBUS_D: 183 case IRQ_NUBUS_E: 184 irq -= NUBUS_SOURCE_BASE; 185 oss->irq_level[irq] = OSS_IRQLEV_NUBUS; 186 return; 187 } 188 189 if (IRQ_SRC(irq) == 1) 190 via_irq_enable(irq); 191 } 192 193 /* 194 * Disable an OSS interrupt 195 * 196 * Same as above except we set the source's interrupt level to zero, 197 * to disable the interrupt. 198 */ 199 200 void oss_irq_disable(int irq) { 201 #ifdef DEBUG_IRQUSE 202 printk("oss_irq_disable(%d)\n", irq); 203 #endif 204 switch(irq) { 205 case IRQ_MAC_SCC: 206 oss->irq_level[OSS_IOPSCC] = 0; 207 return; 208 case IRQ_MAC_ADB: 209 oss->irq_level[OSS_IOPISM] = 0; 210 return; 211 case IRQ_MAC_SCSI: 212 oss->irq_level[OSS_SCSI] = 0; 213 return; 214 case IRQ_NUBUS_9: 215 case IRQ_NUBUS_A: 216 case IRQ_NUBUS_B: 217 case IRQ_NUBUS_C: 218 case IRQ_NUBUS_D: 219 case IRQ_NUBUS_E: 220 irq -= NUBUS_SOURCE_BASE; 221 oss->irq_level[irq] = 0; 222 return; 223 } 224 225 if (IRQ_SRC(irq) == 1) 226 via_irq_disable(irq); 227 } 228