ecard.c

上传linux-jx2410的源代码

/*
 *  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/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/reboot.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/notifier.h>
#include <linux/init.h>

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

#ifndef CONFIG_ARCH_RPC
#define HAVE_EXPMASK
#endif

enum req {
	req_readbytes,
	req_reset_all
};

struct ecard_request {
	enum req	req;
	ecard_t		*ec;
	unsigned int	address;
	unsigned int	length;
	unsigned int	use_loader;
	void		*buffer;
};

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(volatile unsigned char *pa, loader_t loader);
asmlinkage extern int
ecard_loader_read(int off, volatile unsigned char *pa, loader_t loader);
extern int setup_arm_irq(int, struct irqaction *);
extern void do_ecard_IRQ(int, struct pt_regs *);


static void
ecard_irq_noexpmask(int intr_no, void *dev_id, struct pt_regs *regs);

static struct irqaction irqexpansioncard = {
	ecard_irq_noexpmask, SA_INTERRUPT, 0, "expansion cards", NULL, NULL
};

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.
 */
#define BUS_ADDR(x) ((((unsigned long)(x)) << 2) + IO_BASE)
#define POD_INT_ADDR(x)	((volatile unsigned char *)\
			 ((BUS_ADDR((x)) - IO_BASE) + IO_START))

static inline void ecard_task_reset(void)
{
	ecard_t *ec;

	for (ec = cards; ec; ec = ec->next)
		if (ec->loader)
			ecard_loader_reset(POD_INT_ADDR(ec->podaddr),
					   ec->loader);
}

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

	if (req->ec->slot_no == 8) {
		/*
		 * 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) {
			*base_addr = 0;
			index = 0;
		}

		/*
		 * Increment the hardware index counter until we get to the
		 * required offset.  The read bytes are discarded.
		 */
		while (index < off) {
			unsigned char byte;
			byte = base_addr[page];
			index += 1;
		}

		while (len--) {
			*buf++ = base_addr[page];
			index += 1;
		}
	} else {

		if (!req->use_loader || !req->ec->loader) {
			off *= 4;
			while (len--) {
				*buf++ = base_addr[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_addr,
							   req->ec->loader);
			}
		}
	}

}

static void ecard_do_request(struct ecard_request *req)
{
	switch (req->req) {
	case req_readbytes:
		ecard_task_readbytes(req);
		break;

	case req_reset_all:
		ecard_task_reset();
		break;
	}
}

#ifdef CONFIG_CPU_32
#include <linux/completion.h>

static pid_t ecard_pid;
static wait_queue_head_t ecard_wait;
static struct ecard_request *ecard_req;

static DECLARE_COMPLETION(ecard_completion);

/*
 * Set up the expansion card daemon's page tables.
 */
static void ecard_init_pgtables(struct mm_struct *mm)
{
	/* 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;
	unsigned int dst_addr = IO_START;

	src_pgd = pgd_offset(mm, IO_BASE);
	dst_pgd = pgd_offset(mm, dst_addr);

	while (dst_addr < IO_START + IO_SIZE) {
		*dst_pgd++ = *src_pgd++;
		dst_addr += PGDIR_SIZE;
	}

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

	while (dst_addr < EASI_START + EASI_SIZE) {
		*dst_pgd++ = *src_pgd++;
		dst_addr += PGDIR_SIZE;
	}

	flush_tlb_range(mm, IO_START, IO_START + IO_SIZE);
	flush_tlb_range(mm, 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)
{
	struct task_struct *tsk = current;

	/*
	 * We don't want /any/ signals, not even SIGKILL
	 */
	sigfillset(&tsk->blocked);
	sigemptyset(&tsk->pending.signal);
	recalc_sigpending(tsk);
	strcpy(tsk->comm, "kecardd");
	daemonize();

	/*
	 * 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;

		do {
			req = xchg(&ecard_req, NULL);

			if (req == NULL) {
				sigemptyset(&tsk->pending.signal);
				interruptible_sleep_on(&ecard_wait);
			}
		} while (req == NULL);

		ecard_do_request(req);
		complete(&ecard_completion);
	}
}

/*
 * 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)
{
	/*
	 * Make sure we have a context that is able to sleep.
	 */
	if (current == &init_task || in_interrupt())
		BUG();

	if (ecard_pid <= 0)
		ecard_pid = kernel_thread(ecard_task, NULL,
				CLONE_FS | CLONE_FILES | CLONE_SIGHAND);

	ecard_req = req;
	wake_up(&ecard_wait);

	/*
	 * Now wait for kecardd to run.
	 */
	wait_for_completion(&ecard_completion);
}
#else
/*
 * On 26-bit processors, we don't need the kcardd thread to access the
 * expansion card loaders.  We do it directly.
 */
#define ecard_call(req)	ecard_do_request(req)
#endif

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

/*
 * This function is responsible for resetting the expansion cards to a
 * sensible state immediately prior to rebooting the system.  This function
 * has process state (keventd), so we can sleep.
 *
 * Possible "val" values here:
 *  SYS_RESTART   -  restarting system
 *  SYS_HALT      - halting system
 *  SYS_POWER_OFF - powering down system
 *
 * We ignore all calls, unless it is a SYS_RESTART call - power down/halts
 * will be followed by a SYS_RESTART if ctrl-alt-del is pressed again.
 */
static int ecard_reboot(struct notifier_block *me, unsigned long val, void *v)
{
	struct ecard_request req;

	if (val != SYS_RESTART)
		return 0;

	/*
	 * Disable the expansion card interrupt
	 */
	disable_irq(IRQ_EXPANSIONCARD);

	/*
	 * If we have any expansion card loader code which will handle
	 * the reset for us, call it now.
	 */
	req.req = req_reset_all;
	ecard_call(&req);

	/*
	 * Disable the expansion card interrupt again, just to be sure.
	 */
	disable_irq(IRQ_EXPANSIONCARD);

	/*
	 * Finally, reset the expansion card interrupt mask to
	 * all enable (RISC OS doesn't set this)
	 */
#ifdef HAS_EXPMASK
	have_expmask = ~0;
	__raw_writeb(have_expmask, EXPMASK_ENABLE);
#endif
	return 0;
}

static struct notifier_block ecard_reboot_notifier = {
	notifier_call:	ecard_reboot,
};



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

	req.req		= req_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 = (loader_t)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 || ec->irqaddr[0] & 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 || ec->fiqaddr[0] & 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
};