ecard.c

linux 内核源代码

/*
 *  linux/arch/arm/kernel/ecard.c
 *
 *  Copyright 1995-2001 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  Find all installed expansion cards, and handle interrupts from them.
 *
 *  Created from information from Acorns RiscOS3 PRMs
 *
 *  08-Dec-1996	RMK	Added code for the 9'th expansion card - the ether
 *			podule slot.
 *  06-May-1997	RMK	Added blacklist for cards whose loader doesn't work.
 *  12-Sep-1997	RMK	Created new handling of interrupt enables/disables
 *			- cards can now register their own routine to control
 *			interrupts (recommended).
 *  29-Sep-1997	RMK	Expansion card interrupt hardware not being re-enabled
 *			on reset from Linux. (Caused cards not to respond
 *			under RiscOS without hard reset).
 *  15-Feb-1998	RMK	Added DMA support
 *  12-Sep-1998	RMK	Added EASI support
 *  10-Jan-1999	RMK	Run loaders in a simulated RISC OS environment.
 *  17-Apr-1999	RMK	Support for EASI Type C cycles.
 */
#define ECARD_C

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/completion.h>
#include <linux/reboot.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/kthread.h>
#include <linux/io.h>

#include <asm/dma.h>
#include <asm/ecard.h>
#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
#include <asm/mach/irq.h>
#include <asm/tlbflush.h>

#include "ecard.h"

#ifndef CONFIG_ARCH_RPC
#define HAVE_EXPMASK
#endif

struct ecard_request {
	void		(*fn)(struct ecard_request *);
	ecard_t		*ec;
	unsigned int	address;
	unsigned int	length;
	unsigned int	use_loader;
	void		*buffer;
	struct completion *complete;
};

struct expcard_blacklist {
	unsigned short	 manufacturer;
	unsigned short	 product;
	const char	*type;
};

static ecard_t *cards;
static ecard_t *slot_to_expcard[MAX_ECARDS];
static unsigned int ectcr;
#ifdef HAS_EXPMASK
static unsigned int have_expmask;
#endif

/* List of descriptions of cards which don't have an extended
 * identification, or chunk directories containing a description.
 */
static struct expcard_blacklist __initdata blacklist[] = {
	{ MANU_ACORN, PROD_ACORN_ETHER1, "Acorn Ether1" }
};

asmlinkage extern int
ecard_loader_reset(unsigned long base, loader_t loader);
asmlinkage extern int
ecard_loader_read(int off, unsigned long base, loader_t loader);

static inline unsigned short ecard_getu16(unsigned char *v)
{
	return v[0] | v[1] << 8;
}

static inline signed long ecard_gets24(unsigned char *v)
{
	return v[0] | v[1] << 8 | v[2] << 16 | ((v[2] & 0x80) ? 0xff000000 : 0);
}

static inline ecard_t *slot_to_ecard(unsigned int slot)
{
	return slot < MAX_ECARDS ? slot_to_expcard[slot] : NULL;
}

/* ===================== Expansion card daemon ======================== */
/*
 * Since the loader programs on the expansion cards need to be run
 * in a specific environment, create a separate task with this
 * environment up, and pass requests to this task as and when we
 * need to.
 *
 * This should allow 99% of loaders to be called from Linux.
 *
 * From a security standpoint, we trust the card vendors.  This
 * may be a misplaced trust.
 */
static void ecard_task_reset(struct ecard_request *req)
{
	struct expansion_card *ec = req->ec;
	struct resource *res;

	res = ec->slot_no == 8
		? &ec->resource[ECARD_RES_MEMC]
		: ec->easi
		  ? &ec->resource[ECARD_RES_EASI]
		  : &ec->resource[ECARD_RES_IOCSYNC];

	ecard_loader_reset(res->start, ec->loader);
}

static void ecard_task_readbytes(struct ecard_request *req)
{
	struct expansion_card *ec = req->ec;
	unsigned char *buf = req->buffer;
	unsigned int len = req->length;
	unsigned int off = req->address;

	if (ec->slot_no == 8) {
		void __iomem *base = (void __iomem *)
				ec->resource[ECARD_RES_MEMC].start;

		/*
		 * The card maintains an index which increments the address
		 * into a 4096-byte page on each access.  We need to keep
		 * track of the counter.
		 */
		static unsigned int index;
		unsigned int page;

		page = (off >> 12) * 4;
		if (page > 256 * 4)
			return;

		off &= 4095;

		/*
		 * If we are reading offset 0, or our current index is
		 * greater than the offset, reset the hardware index counter.
		 */
		if (off == 0 || index > off) {
			writeb(0, base);
			index = 0;
		}

		/*
		 * Increment the hardware index counter until we get to the
		 * required offset.  The read bytes are discarded.
		 */
		while (index < off) {
			readb(base + page);
			index += 1;
		}

		while (len--) {
			*buf++ = readb(base + page);
			index += 1;
		}
	} else {
		unsigned long base = (ec->easi
			 ? &ec->resource[ECARD_RES_EASI]
			 : &ec->resource[ECARD_RES_IOCSYNC])->start;
		void __iomem *pbase = (void __iomem *)base;

		if (!req->use_loader || !ec->loader) {
			off *= 4;
			while (len--) {
				*buf++ = readb(pbase + off);
				off += 4;
			}
		} else {
			while(len--) {
				/*
				 * The following is required by some
				 * expansion card loader programs.
				 */
				*(unsigned long *)0x108 = 0;
				*buf++ = ecard_loader_read(off++, base,
							   ec->loader);
			}
		}
	}

}

static DECLARE_WAIT_QUEUE_HEAD(ecard_wait);
static struct ecard_request *ecard_req;
static DEFINE_MUTEX(ecard_mutex);

/*
 * Set up the expansion card daemon's page tables.
 */
static void ecard_init_pgtables(struct mm_struct *mm)
{
	struct vm_area_struct vma;

	/* We want to set up the page tables for the following mapping:
	 *  Virtual	Physical
	 *  0x03000000	0x03000000
	 *  0x03010000	unmapped
	 *  0x03210000	0x03210000
	 *  0x03400000	unmapped
	 *  0x08000000	0x08000000
	 *  0x10000000	unmapped
	 *
	 * FIXME: we don't follow this 100% yet.
	 */
	pgd_t *src_pgd, *dst_pgd;

	src_pgd = pgd_offset(mm, (unsigned long)IO_BASE);
	dst_pgd = pgd_offset(mm, IO_START);

	memcpy(dst_pgd, src_pgd, sizeof(pgd_t) * (IO_SIZE / PGDIR_SIZE));

	src_pgd = pgd_offset(mm, EASI_BASE);
	dst_pgd = pgd_offset(mm, EASI_START);

	memcpy(dst_pgd, src_pgd, sizeof(pgd_t) * (EASI_SIZE / PGDIR_SIZE));

	vma.vm_mm = mm;

	flush_tlb_range(&vma, IO_START, IO_START + IO_SIZE);
	flush_tlb_range(&vma, EASI_START, EASI_START + EASI_SIZE);
}

static int ecard_init_mm(void)
{
	struct mm_struct * mm = mm_alloc();
	struct mm_struct *active_mm = current->active_mm;

	if (!mm)
		return -ENOMEM;

	current->mm = mm;
	current->active_mm = mm;
	activate_mm(active_mm, mm);
	mmdrop(active_mm);
	ecard_init_pgtables(mm);
	return 0;
}

static int
ecard_task(void * unused)
{
	/*
	 * Allocate a mm.  We're not a lazy-TLB kernel task since we need
	 * to set page table entries where the user space would be.  Note
	 * that this also creates the page tables.  Failure is not an
	 * option here.
	 */
	if (ecard_init_mm())
		panic("kecardd: unable to alloc mm\n");

	while (1) {
		struct ecard_request *req;

		wait_event_interruptible(ecard_wait, ecard_req != NULL);

		req = xchg(&ecard_req, NULL);
		if (req != NULL) {
			req->fn(req);
			complete(req->complete);
		}
	}
}

/*
 * Wake the expansion card daemon to action our request.
 *
 * FIXME: The test here is not sufficient to detect if the
 * kcardd is running.
 */
static void ecard_call(struct ecard_request *req)
{
	DECLARE_COMPLETION_ONSTACK(completion);

	req->complete = &completion;

	mutex_lock(&ecard_mutex);
	ecard_req = req;
	wake_up(&ecard_wait);

	/*
	 * Now wait for kecardd to run.
	 */
	wait_for_completion(&completion);
	mutex_unlock(&ecard_mutex);
}

/* ======================= Mid-level card control ===================== */

static void
ecard_readbytes(void *addr, ecard_t *ec, int off, int len, int useld)
{
	struct ecard_request req;

	req.fn		= ecard_task_readbytes;
	req.ec		= ec;
	req.address	= off;
	req.length	= len;
	req.use_loader	= useld;
	req.buffer	= addr;

	ecard_call(&req);
}

int ecard_readchunk(struct in_chunk_dir *cd, ecard_t *ec, int id, int num)
{
	struct ex_chunk_dir excd;
	int index = 16;
	int useld = 0;

	if (!ec->cid.cd)
		return 0;

	while(1) {
		ecard_readbytes(&excd, ec, index, 8, useld);
		index += 8;
		if (c_id(&excd) == 0) {
			if (!useld && ec->loader) {
				useld = 1;
				index = 0;
				continue;
			}
			return 0;
		}
		if (c_id(&excd) == 0xf0) { /* link */
			index = c_start(&excd);
			continue;
		}
		if (c_id(&excd) == 0x80) { /* loader */
			if (!ec->loader) {
				ec->loader = kmalloc(c_len(&excd),
							       GFP_KERNEL);
				if (ec->loader)
					ecard_readbytes(ec->loader, ec,
							(int)c_start(&excd),
							c_len(&excd), useld);
				else
					return 0;
			}
			continue;
		}
		if (c_id(&excd) == id && num-- == 0)
			break;
	}

	if (c_id(&excd) & 0x80) {
		switch (c_id(&excd) & 0x70) {
		case 0x70:
			ecard_readbytes((unsigned char *)excd.d.string, ec,
					(int)c_start(&excd), c_len(&excd),
					useld);
			break;
		case 0x00:
			break;
		}
	}
	cd->start_offset = c_start(&excd);
	memcpy(cd->d.string, excd.d.string, 256);
	return 1;
}

/* ======================= Interrupt control ============================ */

static void ecard_def_irq_enable(ecard_t *ec, int irqnr)
{
#ifdef HAS_EXPMASK
	if (irqnr < 4 && have_expmask) {
		have_expmask |= 1 << irqnr;
		__raw_writeb(have_expmask, EXPMASK_ENABLE);
	}
#endif
}

static void ecard_def_irq_disable(ecard_t *ec, int irqnr)
{
#ifdef HAS_EXPMASK
	if (irqnr < 4 && have_expmask) {
		have_expmask &= ~(1 << irqnr);
		__raw_writeb(have_expmask, EXPMASK_ENABLE);
	}
#endif
}

static int ecard_def_irq_pending(ecard_t *ec)
{
	return !ec->irqmask || readb(ec->irqaddr) & ec->irqmask;
}

static void ecard_def_fiq_enable(ecard_t *ec, int fiqnr)
{
	panic("ecard_def_fiq_enable called - impossible");
}

static void ecard_def_fiq_disable(ecard_t *ec, int fiqnr)
{
	panic("ecard_def_fiq_disable called - impossible");
}

static int ecard_def_fiq_pending(ecard_t *ec)
{
	return !ec->fiqmask || readb(ec->fiqaddr) & ec->fiqmask;
}

static expansioncard_ops_t ecard_default_ops = {
	ecard_def_irq_enable,
	ecard_def_irq_disable,
	ecard_def_irq_pending,
	ecard_def_fiq_enable,
	ecard_def_fiq_disable,
	ecard_def_fiq_pending
};

/*
 * Enable and disable interrupts from expansion cards.
 * (interrupts are disabled for these functions).
 *
 * They are not meant to be called directly, but via enable/disable_irq.
 */
static void ecard_irq_unmask(unsigned int irqnr)
{
	ecard_t *ec = slot_to_ecard(irqnr - 32);

	if (ec) {
		if (!ec->ops)
			ec->ops = &ecard_default_ops;

		if (ec->claimed && ec->ops->irqenable)
			ec->ops->irqenable(ec, irqnr);
		else
			printk(KERN_ERR "ecard: rejecting request to "
				"enable IRQs for %d\n", irqnr);
	}
}

static void ecard_irq_mask(unsigned int irqnr)
{
	ecard_t *ec = slot_to_ecard(irqnr - 32);

	if (ec) {
		if (!ec->ops)
			ec->ops = &ecard_default_ops;

		if (ec->ops && ec->ops->irqdisable)
			ec->ops->irqdisable(ec, irqnr);
	}
}

static struct irq_chip ecard_chip = {
	.name	= "ECARD",
	.ack	= ecard_irq_mask,
	.mask	= ecard_irq_mask,
	.unmask = ecard_irq_unmask,
};

void ecard_enablefiq(unsigned int fiqnr)
{
	ecard_t *ec = slot_to_ecard(fiqnr);

	if (ec) {
		if (!ec->ops)
			ec->ops = &ecard_default_ops;

		if (ec->claimed && ec->ops->fiqenable)
			ec->ops->fiqenable(ec, fiqnr);
		else
			printk(KERN_ERR "ecard: rejecting request to "
				"enable FIQs for %d\n", fiqnr);
	}
}

void ecard_disablefiq(unsigned int fiqnr)
{
	ecard_t *ec = slot_to_ecard(fiqnr);

	if (ec) {
		if (!ec->ops)
			ec->ops = &ecard_default_ops;

		if (ec->ops->fiqdisable)
			ec->ops->fiqdisable(ec, fiqnr);
	}
}

static void ecard_dump_irq_state(void)
{
	ecard_t *ec;

	printk("Expansion card IRQ state:\n");

	for (ec = cards; ec; ec = ec->next) {
		if (ec->slot_no == 8)
			continue;

		printk("  %d: %sclaimed, ",
		       ec->slot_no, ec->claimed ? "" : "not ");

		if (ec->ops && ec->ops->irqpending &&
		    ec->ops != &ecard_default_ops)
			printk("irq %spending\n",
			       ec->ops->irqpending(ec) ? "" : "not ");
		else
			printk("irqaddr %p, mask = %02X, status = %02X\n",
			       ec->irqaddr, ec->irqmask, readb(ec->irqaddr));
	}
}

static void ecard_check_lockup(struct irq_desc *desc)
{
	static unsigned long last;
	static int lockup;

	/*
	 * If the timer interrupt has not run since the last million
	 * unrecognised expansion card interrupts, then there is
	 * something seriously wrong.  Disable the expansion card
	 * interrupts so at least we can continue.
	 *
	 * Maybe we ought to start a timer to re-enable them some time
	 * later?
	 */
	if (last == jiffies) {
		lockup += 1;
		if (lockup > 1000000) {
			printk(KERN_ERR "\nInterrupt lockup detected - "
			       "disabling all expansion card interrupts\n");

			desc->chip->mask(IRQ_EXPANSIONCARD);
			ecard_dump_irq_state();
		}
	} else
		lockup = 0;

	/*
	 * If we did not recognise the source of this interrupt,
	 * warn the user, but don't flood the user with these messages.
	 */
	if (!last || time_after(jiffies, last + 5*HZ)) {
		last = jiffies;
		printk(KERN_WARNING "Unrecognised interrupt from backplane\n");
		ecard_dump_irq_state();
	}
}

static void
ecard_irq_handler(unsigned int irq, struct irq_desc *desc)
{
	ecard_t *ec;
	int called = 0;

	desc->chip->mask(irq);
	for (ec = cards; ec; ec = ec->next) {
		int pending;

		if (!ec->claimed || ec->irq == NO_IRQ || ec->slot_no == 8)
			continue;

		if (ec->ops && ec->ops->irqpending)
			pending = ec->ops->irqpending(ec);
		else
			pending = ecard_default_ops.irqpending(ec);

		if (pending) {
			struct irq_desc *d = irq_desc + ec->irq;
			desc_handle_irq(ec->irq, d);
			called ++;
		}
	}
	desc->chip->unmask(irq);

	if (called == 0)
		ecard_check_lockup(desc);
}

#ifdef HAS_EXPMASK
static unsigned char priority_masks[] =
{
	0xf0, 0xf1, 0xf3, 0xf7, 0xff, 0xff, 0xff, 0xff
};

static unsigned char first_set[] =
{
	0x00, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00,
	0x03, 0x00, 0x01, 0x00, 0x02, 0x00, 0x01, 0x00
};

static void
ecard_irqexp_handler(unsigned int irq, struct irq_desc *desc)
{
	const unsigned int statusmask = 15;
	unsigned int status;

	status = __raw_readb(EXPMASK_STATUS) & statusmask;
	if (status) {
		unsigned int slot = first_set[status];
		ecard_t *ec = slot_to_ecard(slot);

		if (ec->claimed) {
			struct irq_desc *d = irq_desc + ec->irq;