#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include "atmel-mci-regs.h"
#define ATMCI_DATA_ERROR_FLAGS (MCI_DCRCE | MCI_DTOE | MCI_OVRE | MCI_UNRE)
+#define ATMCI_DMA_THRESHOLD 16
enum {
EVENT_CMD_COMPLETE = 0,
STATE_DATA_ERROR,
};
+struct atmel_mci_dma {
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+ struct dma_client client;
+ struct dma_chan *chan;
+ struct dma_async_tx_descriptor *data_desc;
+#endif
+};
+
/**
* struct atmel_mci - MMC controller state shared between all slots
* @lock: Spinlock protecting the queue and associated data.
* @cmd: The command currently being sent to the card, or NULL.
* @data: The data currently being transferred, or NULL if no data
* transfer is in progress.
+ * @dma: DMA client state.
+ * @data_chan: DMA channel being used for the current data transfer.
* @cmd_status: Snapshot of SR taken upon completion of the current
* command. Only valid when EVENT_CMD_COMPLETE is pending.
* @data_status: Snapshot of SR taken upon completion of the current
struct mmc_command *cmd;
struct mmc_data *data;
+ struct atmel_mci_dma dma;
+ struct dma_chan *data_chan;
+
u32 cmd_status;
u32 data_status;
u32 stop_cmdr;
mci_writel(host, IER, MCI_CMDRDY);
}
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+static void atmci_dma_cleanup(struct atmel_mci *host)
+{
+ struct mmc_data *data = host->data;
+
+ dma_unmap_sg(&host->pdev->dev, data->sg, data->sg_len,
+ ((data->flags & MMC_DATA_WRITE)
+ ? DMA_TO_DEVICE : DMA_FROM_DEVICE));
+}
+
+static void atmci_stop_dma(struct atmel_mci *host)
+{
+ struct dma_chan *chan = host->data_chan;
+
+ if (chan) {
+ chan->device->device_terminate_all(chan);
+ atmci_dma_cleanup(host);
+ } else {
+ /* Data transfer was stopped by the interrupt handler */
+ atmci_set_pending(host, EVENT_XFER_COMPLETE);
+ mci_writel(host, IER, MCI_NOTBUSY);
+ }
+}
+
+/* This function is called by the DMA driver from tasklet context. */
+static void atmci_dma_complete(void *arg)
+{
+ struct atmel_mci *host = arg;
+ struct mmc_data *data = host->data;
+
+ dev_vdbg(&host->pdev->dev, "DMA complete\n");
+
+ atmci_dma_cleanup(host);
+
+ /*
+ * If the card was removed, data will be NULL. No point trying
+ * to send the stop command or waiting for NBUSY in this case.
+ */
+ if (data) {
+ atmci_set_pending(host, EVENT_XFER_COMPLETE);
+ tasklet_schedule(&host->tasklet);
+
+ /*
+ * Regardless of what the documentation says, we have
+ * to wait for NOTBUSY even after block read
+ * operations.
+ *
+ * When the DMA transfer is complete, the controller
+ * may still be reading the CRC from the card, i.e.
+ * the data transfer is still in progress and we
+ * haven't seen all the potential error bits yet.
+ *
+ * The interrupt handler will schedule a different
+ * tasklet to finish things up when the data transfer
+ * is completely done.
+ *
+ * We may not complete the mmc request here anyway
+ * because the mmc layer may call back and cause us to
+ * violate the "don't submit new operations from the
+ * completion callback" rule of the dma engine
+ * framework.
+ */
+ mci_writel(host, IER, MCI_NOTBUSY);
+ }
+}
+
+static int
+atmci_submit_data_dma(struct atmel_mci *host, struct mmc_data *data)
+{
+ struct dma_chan *chan;
+ struct dma_async_tx_descriptor *desc;
+ struct scatterlist *sg;
+ unsigned int i;
+ enum dma_data_direction direction;
+
+ /*
+ * We don't do DMA on "complex" transfers, i.e. with
+ * non-word-aligned buffers or lengths. Also, we don't bother
+ * with all the DMA setup overhead for short transfers.
+ */
+ if (data->blocks * data->blksz < ATMCI_DMA_THRESHOLD)
+ return -EINVAL;
+ if (data->blksz & 3)
+ return -EINVAL;
+
+ for_each_sg(data->sg, sg, data->sg_len, i) {
+ if (sg->offset & 3 || sg->length & 3)
+ return -EINVAL;
+ }
+
+ /* If we don't have a channel, we can't do DMA */
+ chan = host->dma.chan;
+ if (chan) {
+ dma_chan_get(chan);
+ host->data_chan = chan;
+ }
+
+ if (!chan)
+ return -ENODEV;
+
+ if (data->flags & MMC_DATA_READ)
+ direction = DMA_FROM_DEVICE;
+ else
+ direction = DMA_TO_DEVICE;
+
+ desc = chan->device->device_prep_slave_sg(chan,
+ data->sg, data->sg_len, direction,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ if (!desc)
+ return -ENOMEM;
+
+ host->dma.data_desc = desc;
+ desc->callback = atmci_dma_complete;
+ desc->callback_param = host;
+ desc->tx_submit(desc);
+
+ /* Go! */
+ chan->device->device_issue_pending(chan);
+
+ return 0;
+}
+
+#else /* CONFIG_MMC_ATMELMCI_DMA */
+
+static int atmci_submit_data_dma(struct atmel_mci *host, struct mmc_data *data)
+{
+ return -ENOSYS;
+}
+
+static void atmci_stop_dma(struct atmel_mci *host)
+{
+ /* Data transfer was stopped by the interrupt handler */
+ atmci_set_pending(host, EVENT_XFER_COMPLETE);
+ mci_writel(host, IER, MCI_NOTBUSY);
+}
+
+#endif /* CONFIG_MMC_ATMELMCI_DMA */
+
/*
* Returns a mask of interrupt flags to be enabled after the whole
* request has been prepared.
host->data = data;
iflags = ATMCI_DATA_ERROR_FLAGS;
+ if (atmci_submit_data_dma(host, data)) {
+ host->data_chan = NULL;
- /*
- * Errata: MMC data write operation with less than 12
- * bytes is impossible.
- *
- * Errata: MCI Transmit Data Register (TDR) FIFO
- * corruption when length is not multiple of 4.
- */
- if (data->blocks * data->blksz < 12
- || (data->blocks * data->blksz) & 3)
- host->need_reset = true;
+ /*
+ * Errata: MMC data write operation with less than 12
+ * bytes is impossible.
+ *
+ * Errata: MCI Transmit Data Register (TDR) FIFO
+ * corruption when length is not multiple of 4.
+ */
+ if (data->blocks * data->blksz < 12
+ || (data->blocks * data->blksz) & 3)
+ host->need_reset = true;
- host->sg = data->sg;
- host->pio_offset = 0;
- if (data->flags & MMC_DATA_READ)
- iflags |= MCI_RXRDY;
- else
- iflags |= MCI_TXRDY;
+ host->sg = data->sg;
+ host->pio_offset = 0;
+ if (data->flags & MMC_DATA_READ)
+ iflags |= MCI_RXRDY;
+ else
+ iflags |= MCI_TXRDY;
+ }
return iflags;
}
if (cmd->data) {
host->data = NULL;
+ atmci_stop_dma(host);
mci_writel(host, IDR, MCI_NOTBUSY
| MCI_TXRDY | MCI_RXRDY
| ATMCI_DATA_ERROR_FLAGS);
/* fall through */
case STATE_SENDING_DATA:
mrq->data->error = -ENOMEDIUM;
+ atmci_stop_dma(host);
break;
case STATE_DATA_BUSY:
case STATE_DATA_ERROR:
case STATE_SENDING_DATA:
if (atmci_test_and_clear_pending(host,
EVENT_DATA_ERROR)) {
+ atmci_stop_dma(host);
if (data->stop)
send_stop_cmd(host, data);
state = STATE_DATA_ERROR;
return IRQ_HANDLED;
}
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+
+static inline struct atmel_mci *
+dma_client_to_atmel_mci(struct dma_client *client)
+{
+ return container_of(client, struct atmel_mci, dma.client);
+}
+
+static enum dma_state_client atmci_dma_event(struct dma_client *client,
+ struct dma_chan *chan, enum dma_state state)
+{
+ struct atmel_mci *host;
+ enum dma_state_client ret = DMA_NAK;
+
+ host = dma_client_to_atmel_mci(client);
+
+ switch (state) {
+ case DMA_RESOURCE_AVAILABLE:
+ spin_lock_bh(&host->lock);
+ if (!host->dma.chan) {
+ host->dma.chan = chan;
+ ret = DMA_ACK;
+ }
+ spin_unlock_bh(&host->lock);
+
+ if (ret == DMA_ACK)
+ dev_info(&host->pdev->dev,
+ "Using %s for DMA transfers\n",
+ chan->dev.bus_id);
+ break;
+
+ case DMA_RESOURCE_REMOVED:
+ spin_lock_bh(&host->lock);
+ if (host->dma.chan == chan) {
+ host->dma.chan = NULL;
+ ret = DMA_ACK;
+ }
+ spin_unlock_bh(&host->lock);
+
+ if (ret == DMA_ACK)
+ dev_info(&host->pdev->dev,
+ "Lost %s, falling back to PIO\n",
+ chan->dev.bus_id);
+ break;
+
+ default:
+ break;
+ }
+
+
+ return ret;
+}
+#endif /* CONFIG_MMC_ATMELMCI_DMA */
+
static int __init atmci_init_slot(struct atmel_mci *host,
struct mci_slot_pdata *slot_data, unsigned int id,
u32 sdc_reg)
if (ret)
goto err_request_irq;
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+ if (pdata->dma_slave) {
+ struct dma_slave *slave = pdata->dma_slave;
+
+ slave->tx_reg = regs->start + MCI_TDR;
+ slave->rx_reg = regs->start + MCI_RDR;
+
+ /* Try to grab a DMA channel */
+ host->dma.client.event_callback = atmci_dma_event;
+ dma_cap_set(DMA_SLAVE, host->dma.client.cap_mask);
+ host->dma.client.slave = slave;
+
+ dma_async_client_register(&host->dma.client);
+ dma_async_client_chan_request(&host->dma.client);
+ } else {
+ dev_notice(&pdev->dev, "DMA not available, using PIO\n");
+ }
+#endif /* CONFIG_MMC_ATMELMCI_DMA */
+
platform_set_drvdata(pdev, host);
/* We need at least one slot to succeed */
return 0;
err_init_slot:
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+ if (pdata->dma_slave)
+ dma_async_client_unregister(&host->dma.client);
+#endif
free_irq(irq, host);
err_request_irq:
iounmap(host->regs);
mci_readl(host, SR);
clk_disable(host->mck);
+#ifdef CONFIG_MMC_ATMELMCI_DMA
+ if (host->dma.client.slave)
+ dma_async_client_unregister(&host->dma.client);
+#endif
+
free_irq(platform_get_irq(pdev, 0), host);
iounmap(host->regs);
projects / openwrt / staging / blogic.git / commitdiff