source: trunk/kernel/drivers/soclib/soclib_dma.c @ 2

/*
 * soclib_dma.c - soclib DMA driver
 *
 * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless
 * Copyright (c) 2011,2012 UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-kernel.
 *
 * ALMOS-kernel is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-kernel is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-kernel; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <errno.h>
#include <cpu.h>
#include <device.h>
#include <driver.h>
#include <drvdb.h>
#include <kmem.h>
#include <scheduler.h>
#include <thread.h>
#include <task.h>
#include <list.h>
#include <event.h>
#include <soclib_dma.h>
#include <string.h>

/* DMA mapped registers offset */
#define DMA_SRC_REG          0
#define DMA_DST_REG          1
#define DMA_LEN_REG          2
#define DMA_RESET_REG        3
#define DMA_IRQ_DISABLED     4

struct dma_context_s
{
        struct list_entry request_queue;
        struct wait_queue_s pending;
};

static void dma_start_request(struct device_s *dma, dev_request_t *ptr)
{
        volatile uint32_t *base = dma->base;
        dev_request_t *rq;

        rq = (ptr->flags & DEV_RQ_NESTED) ? ptr->data : ptr;

        base[DMA_SRC_REG]      = (unsigned int)rq->src;
        base[DMA_DST_REG]      = (unsigned int)rq->dst;
        base[DMA_IRQ_DISABLED] = 0;
        base[DMA_LEN_REG]      = rq->count;
}

static void dma_irq_handler(struct irq_action_s *action)
{
        struct dma_context_s *ctx;
        struct device_s *dma;
        dev_request_t *rq;
        dev_request_t *frag;
        dev_request_t *new_rq;
        error_t err;
        volatile uint32_t *base;
        struct thread_s *this;

        dma  = action->dev;
        base = dma->base;
        ctx  = (struct dma_context_s*)dma->data;

        cpu_spinlock_lock(&dma->lock.val);
  
        err = base[DMA_LEN_REG];
        base[DMA_RESET_REG] = 0;

        /* even if this case is realy low probable, we have to check for empty list ! */
        if(list_empty(&ctx->request_queue))
        {
                cpu_spinlock_unlock(&dma->lock.val);
                return;
        }

        rq = list_first(&ctx->request_queue, dev_request_t, list);

        if(rq->flags & DEV_RQ_NESTED)
        {
                frag = rq->data;

                event_set_error(&frag->event, err);
                event_set_senderId(&frag->event, dma);
                event_send(&frag->event, current_cpu->gid);

                if((err == 0) && (frag->data != NULL))
                {
                        rq->data = frag->data;
                        dma_start_request(dma,frag->data);
                        cpu_spinlock_unlock(&dma->lock.val);
                        return;
                }
        }

        list_unlink(&rq->list);
  
        if(!(list_empty(&ctx->request_queue)))
        {
                new_rq = list_first(&ctx->request_queue, dev_request_t, list);
                dma_start_request(dma,new_rq);
        }
  
        if(!(rq->flags & DEV_RQ_NOBLOCK))
        {
                rq->err = err;
                wakeup_one(&ctx->pending, WAIT_FIRST);
                cpu_spinlock_unlock(&dma->lock.val);
                return;
        }
  
        cpu_spinlock_unlock(&dma->lock.val);

        this = CURRENT_THREAD;
 
        event_set_error(&rq->event, err);
        event_set_senderId(&rq->event, dma);
        event_send(&rq->event, current_cpu->gid);
}

static void dma_fraglist_destroy(dev_request_t *ptr)
{
        kmem_req_t req;
        dev_request_t *frag;

        req.type = KMEM_DMA_REQUEST;
        frag     = ptr;

        while(frag != NULL);
        {
                req.ptr = frag;
                frag    = frag->data;

                kmem_free(&req);
        }
}

static EVENT_HANDLER(dma_async_frag_event)
{
        dev_request_t *frag;
        kmem_req_t req;
        error_t err;

        frag = event_get_argument(event);
        err  = event_get_error(event);

        assert(frag != NULL && "corrupted frag");

        if(err)
        {
                dma_fraglist_destroy(frag);
                return 0;
        }

        req.type = KMEM_DMA_REQUEST;
        req.ptr  = frag;

        kmem_free(&req);
        return 0;
}

static error_t dma_frag_init(dev_request_t *frag, uint_t src_start, uint_t dst_start, uint_t count)
{
        //FIXME(40) use extent registers
        frag->src   = task_vaddr2paddr(current_task, (void*)src_start);
        frag->dst   = task_vaddr2paddr(current_task, (void*)dst_start);
        frag->count = count;
        frag->flags = 0;

        if((frag->src == NULL) || (frag->dst == NULL))
                return EPERM;

        event_set_priority(&frag->event, E_FUNC);
        event_set_handler(&frag->event, &dma_async_frag_event);
        event_set_argument(&frag->event, frag);
        return 0;
}

static error_t dma_fraglist_build(dev_request_t *rq)
{
        kmem_req_t req;
        dev_request_t *frag;
        dev_request_t *parent_frag;
        struct slist_entry *root;
        struct slist_entry *iter;
        uint_t src_start;
        uint_t dst_start;
        uint_t count;
        error_t err;

        if(rq->count == 0)
                return EINVAL;

        src_start = (uint_t)rq->src;
        dst_start = (uint_t)rq->dst;

        if((src_start + rq->count) <= ((src_start & ~PMM_PAGE_MASK) + PMM_PAGE_SIZE) &&
           (dst_start + rq->count) <= ((dst_start & ~PMM_PAGE_MASK) + PMM_PAGE_SIZE))
        {
                //FIXME(40) use extent registers
                rq->src = task_vaddr2paddr(current_task, rq->src);
                rq->dst = task_vaddr2paddr(current_task, rq->dst);

                if((rq->src == NULL) || (rq->dst == NULL))
                        return EPERM;

                return 0;
        }

        if((src_start & PMM_PAGE_MASK) || (dst_start & PMM_PAGE_MASK)) {
                return ENOSYS;
        }

        req.type    = KMEM_DMA_REQUEST;
        req.size    = sizeof(*rq);
        req.flags   = AF_KERNEL;
        root        = (struct slist_entry *)&rq->data;
        iter        = (struct slist_entry *)&rq->list;
        count       = rq->count;
        rq->data    = NULL;
        rq->flags  &= ~DEV_RQ_NESTED;
        parent_frag = rq;

        while(count)
        {
                frag = kmem_alloc(&req);

                if(frag == NULL)
                {
                        err = ENOMEM;
                        goto fail_nomem;
                }

                if(count >= PMM_PAGE_SIZE)
                {
                        err = dma_frag_init(frag, src_start, dst_start, PMM_PAGE_SIZE);

                        if(err)
                                goto fail_init;

                        src_start += PMM_PAGE_SIZE;
                        dst_start += PMM_PAGE_SIZE;
                        count     -= PMM_PAGE_SIZE;
                }
                else
                {
                        err = dma_frag_init(frag, src_start, dst_start, count);

                        if(err)
                                goto fail_init;

                        count -= count;
                }

                parent_frag->data = frag;
                frag->data        = NULL;
                parent_frag       = frag;
        }

        rq->flags |= DEV_RQ_NESTED;
        return 0;

fail_init:
fail_nomem:
        dma_fraglist_destroy(rq->data);
        return err;
}


static sint_t dma_request(struct device_s *dma, dev_request_t *rq)
{
        struct dma_context_s *ctx;
        uint_t irq_state;
        sint_t err;

        rq->err = 0;
        ctx     = (struct dma_context_s*)dma->data;

        err = dma_fraglist_build(rq);

        if(err)
                return err;

        spinlock_lock_noirq(&dma->lock,&irq_state);

        if(list_empty(&ctx->request_queue))
        {
                list_add(&ctx->request_queue, &rq->list);
                dma_start_request(dma, rq);
        }
        else
                list_add_last(&ctx->request_queue, &rq->list);

        if(rq->flags & DEV_RQ_NOBLOCK)
        {
                spinlock_unlock_noirq(&dma->lock, irq_state);
                return 0;
        }

        wait_on(&ctx->pending, WAIT_LAST);
        spinlock_unlock_noirq(&dma->lock,irq_state);
        sched_sleep(CURRENT_THREAD);

        return rq->err;
}

static sint_t dma_open(struct device_s *dma, dev_request_t *rq)
{
        return EPERM;
}

struct device_s *__sys_dma;
static uint_t dma_count = 0;

error_t soclib_dma_init(struct device_s *dma)
{
        kmem_req_t req;
        struct dma_context_s *ctx;

        spinlock_init(&dma->lock,"DevDMA (SoCLib)");
        dma->type = DEV_BLK;

        dma->action.dev         = dma;
        dma->action.irq_handler = &dma_irq_handler;
        dma->action.data        = NULL;

        if(dma_count == 0)
                __sys_dma = dma;

        sprintk(dma->name, 
#if CONFIG_ROOTFS_IS_VFAT
                "DMA%d"
#else
                "dma%d"
#endif
                ,dma_count++);

        metafs_init(&dma->node, dma->name);
  
        dma->op.dev.open       = &dma_open;
        dma->op.dev.read       = &dma_request;
        dma->op.dev.write      = &dma_request;
        dma->op.dev.close      = NULL;
        dma->op.dev.lseek      = NULL;
        dma->op.dev.mmap       = NULL;
        dma->op.dev.munmap     = NULL;
        dma->op.dev.set_params = NULL;
        dma->op.dev.get_params = NULL;
        dma->op.drvid          = SOCLIB_DMA_ID;

        req.type  = KMEM_GENERIC;
        req.size  = sizeof(*ctx);
        req.flags = AF_BOOT | AF_ZERO;
  
        if((ctx = kmem_alloc(&req)) == NULL)
                return ENOMEM;

        wait_queue_init(&ctx->pending, dma->name);
        list_root_init(&ctx->request_queue);
        dma->data = (void *)ctx;
        return 0;
}

driver_t soclib_dma_driver = { .init = &soclib_dma_init };