285 lines
6.5 KiB
C
285 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Driver for the ADB controller in the Mac I/O (Hydra) chip.
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*/
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#include <stdarg.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/delay.h>
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#include <linux/spinlock.h>
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#include <linux/interrupt.h>
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#include <asm/prom.h>
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#include <linux/adb.h>
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#include <asm/io.h>
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#include <asm/pgtable.h>
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#include <asm/hydra.h>
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#include <asm/irq.h>
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#include <linux/init.h>
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#include <linux/ioport.h>
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struct preg {
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unsigned char r;
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char pad[15];
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};
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struct adb_regs {
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struct preg intr;
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struct preg data[9];
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struct preg intr_enb;
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struct preg dcount;
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struct preg error;
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struct preg ctrl;
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struct preg autopoll;
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struct preg active_hi;
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struct preg active_lo;
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struct preg test;
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};
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/* Bits in intr and intr_enb registers */
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#define DFB 1 /* data from bus */
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#define TAG 2 /* transfer access grant */
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/* Bits in dcount register */
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#define HMB 0x0f /* how many bytes */
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#define APD 0x10 /* auto-poll data */
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/* Bits in error register */
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#define NRE 1 /* no response error */
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#define DLE 2 /* data lost error */
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/* Bits in ctrl register */
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#define TAR 1 /* transfer access request */
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#define DTB 2 /* data to bus */
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#define CRE 4 /* command response expected */
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#define ADB_RST 8 /* ADB reset */
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/* Bits in autopoll register */
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#define APE 1 /* autopoll enable */
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static volatile struct adb_regs __iomem *adb;
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static struct adb_request *current_req, *last_req;
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static DEFINE_SPINLOCK(macio_lock);
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static int macio_probe(void);
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static int macio_init(void);
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static irqreturn_t macio_adb_interrupt(int irq, void *arg);
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static int macio_send_request(struct adb_request *req, int sync);
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static int macio_adb_autopoll(int devs);
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static void macio_adb_poll(void);
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static int macio_adb_reset_bus(void);
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struct adb_driver macio_adb_driver = {
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.name = "MACIO",
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.probe = macio_probe,
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.init = macio_init,
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.send_request = macio_send_request,
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.autopoll = macio_adb_autopoll,
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.poll = macio_adb_poll,
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.reset_bus = macio_adb_reset_bus,
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};
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int macio_probe(void)
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{
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struct device_node *np;
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np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
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if (np) {
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of_node_put(np);
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return 0;
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}
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return -ENODEV;
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}
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int macio_init(void)
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{
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struct device_node *adbs;
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struct resource r;
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unsigned int irq;
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adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
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if (adbs == 0)
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return -ENXIO;
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if (of_address_to_resource(adbs, 0, &r)) {
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of_node_put(adbs);
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return -ENXIO;
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}
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adb = ioremap(r.start, sizeof(struct adb_regs));
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out_8(&adb->ctrl.r, 0);
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out_8(&adb->intr.r, 0);
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out_8(&adb->error.r, 0);
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out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
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out_8(&adb->active_lo.r, 0xff);
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out_8(&adb->autopoll.r, APE);
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irq = irq_of_parse_and_map(adbs, 0);
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of_node_put(adbs);
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if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
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printk(KERN_ERR "ADB: can't get irq %d\n", irq);
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return -EAGAIN;
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}
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out_8(&adb->intr_enb.r, DFB | TAG);
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printk("adb: mac-io driver 1.0 for unified ADB\n");
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return 0;
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}
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static int macio_adb_autopoll(int devs)
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{
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unsigned long flags;
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spin_lock_irqsave(&macio_lock, flags);
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out_8(&adb->active_hi.r, devs >> 8);
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out_8(&adb->active_lo.r, devs);
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out_8(&adb->autopoll.r, devs? APE: 0);
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spin_unlock_irqrestore(&macio_lock, flags);
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return 0;
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}
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static int macio_adb_reset_bus(void)
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{
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unsigned long flags;
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int timeout = 1000000;
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/* Hrm... we may want to not lock interrupts for so
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* long ... oh well, who uses that chip anyway ? :)
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* That function will be seldom used during boot
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* on rare machines, so...
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*/
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spin_lock_irqsave(&macio_lock, flags);
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out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
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while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
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if (--timeout == 0) {
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out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
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spin_unlock_irqrestore(&macio_lock, flags);
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return -1;
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}
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}
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spin_unlock_irqrestore(&macio_lock, flags);
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return 0;
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}
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/* Send an ADB command */
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static int macio_send_request(struct adb_request *req, int sync)
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{
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unsigned long flags;
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int i;
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if (req->data[0] != ADB_PACKET)
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return -EINVAL;
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for (i = 0; i < req->nbytes - 1; ++i)
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req->data[i] = req->data[i+1];
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--req->nbytes;
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req->next = NULL;
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req->sent = 0;
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req->complete = 0;
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req->reply_len = 0;
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spin_lock_irqsave(&macio_lock, flags);
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if (current_req != 0) {
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last_req->next = req;
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last_req = req;
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} else {
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current_req = last_req = req;
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out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
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}
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spin_unlock_irqrestore(&macio_lock, flags);
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if (sync) {
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while (!req->complete)
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macio_adb_poll();
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}
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return 0;
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}
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static irqreturn_t macio_adb_interrupt(int irq, void *arg)
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{
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int i, n, err;
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struct adb_request *req = NULL;
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unsigned char ibuf[16];
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int ibuf_len = 0;
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int complete = 0;
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int autopoll = 0;
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int handled = 0;
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spin_lock(&macio_lock);
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if (in_8(&adb->intr.r) & TAG) {
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handled = 1;
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if ((req = current_req) != 0) {
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/* put the current request in */
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for (i = 0; i < req->nbytes; ++i)
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out_8(&adb->data[i].r, req->data[i]);
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out_8(&adb->dcount.r, req->nbytes & HMB);
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req->sent = 1;
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if (req->reply_expected) {
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out_8(&adb->ctrl.r, DTB + CRE);
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} else {
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out_8(&adb->ctrl.r, DTB);
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current_req = req->next;
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complete = 1;
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if (current_req)
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out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
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}
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}
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out_8(&adb->intr.r, 0);
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}
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if (in_8(&adb->intr.r) & DFB) {
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handled = 1;
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err = in_8(&adb->error.r);
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if (current_req && current_req->sent) {
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/* this is the response to a command */
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req = current_req;
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if (err == 0) {
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req->reply_len = in_8(&adb->dcount.r) & HMB;
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for (i = 0; i < req->reply_len; ++i)
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req->reply[i] = in_8(&adb->data[i].r);
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}
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current_req = req->next;
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complete = 1;
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if (current_req)
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out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
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} else if (err == 0) {
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/* autopoll data */
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n = in_8(&adb->dcount.r) & HMB;
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for (i = 0; i < n; ++i)
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ibuf[i] = in_8(&adb->data[i].r);
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ibuf_len = n;
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autopoll = (in_8(&adb->dcount.r) & APD) != 0;
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}
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out_8(&adb->error.r, 0);
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out_8(&adb->intr.r, 0);
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}
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spin_unlock(&macio_lock);
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if (complete && req) {
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void (*done)(struct adb_request *) = req->done;
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mb();
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req->complete = 1;
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/* Here, we assume that if the request has a done member, the
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* struct request will survive to setting req->complete to 1
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*/
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if (done)
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(*done)(req);
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}
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if (ibuf_len)
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adb_input(ibuf, ibuf_len, autopoll);
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return IRQ_RETVAL(handled);
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}
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static void macio_adb_poll(void)
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{
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unsigned long flags;
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local_irq_save(flags);
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if (in_8(&adb->intr.r) != 0)
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macio_adb_interrupt(0, NULL);
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local_irq_restore(flags);
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}
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