root/drivers/usb/musb/ux500_dma.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * drivers/usb/musb/ux500_dma.c
 *
 * U8500 DMA support code
 *
 * Copyright (C) 2009 STMicroelectronics
 * Copyright (C) 2011 ST-Ericsson SA
 * Authors:
 *      Mian Yousaf Kaukab <mian.yousaf.kaukab@stericsson.com>
 *      Praveena Nadahally <praveen.nadahally@stericsson.com>
 *      Rajaram Regupathy <ragupathy.rajaram@stericsson.com>
 */

#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/pfn.h>
#include <linux/sizes.h>
#include <linux/platform_data/usb-musb-ux500.h>
#include "musb_core.h"

static const char *iep_chan_names[] = { "iep_1_9", "iep_2_10", "iep_3_11", "iep_4_12",
                                        "iep_5_13", "iep_6_14", "iep_7_15", "iep_8" };
static const char *oep_chan_names[] = { "oep_1_9", "oep_2_10", "oep_3_11", "oep_4_12",
                                        "oep_5_13", "oep_6_14", "oep_7_15", "oep_8" };

struct ux500_dma_channel {
        struct dma_channel channel;
        struct ux500_dma_controller *controller;
        struct musb_hw_ep *hw_ep;
        struct dma_chan *dma_chan;
        unsigned int cur_len;
        dma_cookie_t cookie;
        u8 ch_num;
        u8 is_tx;
        u8 is_allocated;
};

struct ux500_dma_controller {
        struct dma_controller controller;
        struct ux500_dma_channel rx_channel[UX500_MUSB_DMA_NUM_RX_TX_CHANNELS];
        struct ux500_dma_channel tx_channel[UX500_MUSB_DMA_NUM_RX_TX_CHANNELS];
        void *private_data;
        dma_addr_t phy_base;
};

/* Work function invoked from DMA callback to handle rx transfers. */
static void ux500_dma_callback(void *private_data)
{
        struct dma_channel *channel = private_data;
        struct ux500_dma_channel *ux500_channel = channel->private_data;
        struct musb_hw_ep       *hw_ep = ux500_channel->hw_ep;
        struct musb *musb = hw_ep->musb;
        unsigned long flags;

        dev_dbg(musb->controller, "DMA rx transfer done on hw_ep=%d\n",
                hw_ep->epnum);

        spin_lock_irqsave(&musb->lock, flags);
        ux500_channel->channel.actual_len = ux500_channel->cur_len;
        ux500_channel->channel.status = MUSB_DMA_STATUS_FREE;
        musb_dma_completion(musb, hw_ep->epnum, ux500_channel->is_tx);
        spin_unlock_irqrestore(&musb->lock, flags);

}

static bool ux500_configure_channel(struct dma_channel *channel,
                                u16 packet_sz, u8 mode,
                                dma_addr_t dma_addr, u32 len)
{
        struct ux500_dma_channel *ux500_channel = channel->private_data;
        struct musb_hw_ep *hw_ep = ux500_channel->hw_ep;
        struct dma_chan *dma_chan = ux500_channel->dma_chan;
        struct dma_async_tx_descriptor *dma_desc;
        enum dma_transfer_direction direction;
        struct scatterlist sg;
        struct dma_slave_config slave_conf;
        enum dma_slave_buswidth addr_width;
        struct musb *musb = ux500_channel->controller->private_data;
        dma_addr_t usb_fifo_addr = (musb->io.fifo_offset(hw_ep->epnum) +
                                        ux500_channel->controller->phy_base);

        dev_dbg(musb->controller,
                "packet_sz=%d, mode=%d, dma_addr=0x%llx, len=%d is_tx=%d\n",
                packet_sz, mode, (unsigned long long) dma_addr,
                len, ux500_channel->is_tx);

        ux500_channel->cur_len = len;

        sg_init_table(&sg, 1);
        sg_set_page(&sg, pfn_to_page(PFN_DOWN(dma_addr)), len,
                                            offset_in_page(dma_addr));
        sg_dma_address(&sg) = dma_addr;
        sg_dma_len(&sg) = len;

        direction = ux500_channel->is_tx ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
        addr_width = (len & 0x3) ? DMA_SLAVE_BUSWIDTH_1_BYTE :
                                        DMA_SLAVE_BUSWIDTH_4_BYTES;

        slave_conf.direction = direction;
        slave_conf.src_addr = usb_fifo_addr;
        slave_conf.src_addr_width = addr_width;
        slave_conf.src_maxburst = 16;
        slave_conf.dst_addr = usb_fifo_addr;
        slave_conf.dst_addr_width = addr_width;
        slave_conf.dst_maxburst = 16;
        slave_conf.device_fc = false;

        dmaengine_slave_config(dma_chan, &slave_conf);

        dma_desc = dmaengine_prep_slave_sg(dma_chan, &sg, 1, direction,
                                             DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!dma_desc)
                return false;

        dma_desc->callback = ux500_dma_callback;
        dma_desc->callback_param = channel;
        ux500_channel->cookie = dma_desc->tx_submit(dma_desc);

        dma_async_issue_pending(dma_chan);

        return true;
}

static struct dma_channel *ux500_dma_channel_allocate(struct dma_controller *c,
                                struct musb_hw_ep *hw_ep, u8 is_tx)
{
        struct ux500_dma_controller *controller = container_of(c,
                        struct ux500_dma_controller, controller);
        struct ux500_dma_channel *ux500_channel = NULL;
        struct musb *musb = controller->private_data;
        u8 ch_num = hw_ep->epnum - 1;

        /* 8 DMA channels (0 - 7). Each DMA channel can only be allocated
         * to specified hw_ep. For example DMA channel 0 can only be allocated
         * to hw_ep 1 and 9.
         */
        if (ch_num > 7)
                ch_num -= 8;

        if (ch_num >= UX500_MUSB_DMA_NUM_RX_TX_CHANNELS)
                return NULL;

        ux500_channel = is_tx ? &(controller->tx_channel[ch_num]) :
                                &(controller->rx_channel[ch_num]) ;

        /* Check if channel is already used. */
        if (ux500_channel->is_allocated)
                return NULL;

        ux500_channel->hw_ep = hw_ep;
        ux500_channel->is_allocated = 1;

        dev_dbg(musb->controller, "hw_ep=%d, is_tx=0x%x, channel=%d\n",
                hw_ep->epnum, is_tx, ch_num);

        return &(ux500_channel->channel);
}

static void ux500_dma_channel_release(struct dma_channel *channel)
{
        struct ux500_dma_channel *ux500_channel = channel->private_data;
        struct musb *musb = ux500_channel->controller->private_data;

        dev_dbg(musb->controller, "channel=%d\n", ux500_channel->ch_num);

        if (ux500_channel->is_allocated) {
                ux500_channel->is_allocated = 0;
                channel->status = MUSB_DMA_STATUS_FREE;
                channel->actual_len = 0;
        }
}

static int ux500_dma_is_compatible(struct dma_channel *channel,
                u16 maxpacket, void *buf, u32 length)
{
        if ((maxpacket & 0x3)           ||
                ((unsigned long int) buf & 0x3) ||
                (length < 512)          ||
                (length & 0x3))
                return false;
        else
                return true;
}

static int ux500_dma_channel_program(struct dma_channel *channel,
                                u16 packet_sz, u8 mode,
                                dma_addr_t dma_addr, u32 len)
{
        int ret;

        BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
                channel->status == MUSB_DMA_STATUS_BUSY);

        channel->status = MUSB_DMA_STATUS_BUSY;
        channel->actual_len = 0;
        ret = ux500_configure_channel(channel, packet_sz, mode, dma_addr, len);
        if (!ret)
                channel->status = MUSB_DMA_STATUS_FREE;

        return ret;
}

static int ux500_dma_channel_abort(struct dma_channel *channel)
{
        struct ux500_dma_channel *ux500_channel = channel->private_data;
        struct ux500_dma_controller *controller = ux500_channel->controller;
        struct musb *musb = controller->private_data;
        void __iomem *epio = musb->endpoints[ux500_channel->hw_ep->epnum].regs;
        u16 csr;

        dev_dbg(musb->controller, "channel=%d, is_tx=%d\n",
                ux500_channel->ch_num, ux500_channel->is_tx);

        if (channel->status == MUSB_DMA_STATUS_BUSY) {
                if (ux500_channel->is_tx) {
                        csr = musb_readw(epio, MUSB_TXCSR);
                        csr &= ~(MUSB_TXCSR_AUTOSET |
                                 MUSB_TXCSR_DMAENAB |
                                 MUSB_TXCSR_DMAMODE);
                        musb_writew(epio, MUSB_TXCSR, csr);
                } else {
                        csr = musb_readw(epio, MUSB_RXCSR);
                        csr &= ~(MUSB_RXCSR_AUTOCLEAR |
                                 MUSB_RXCSR_DMAENAB |
                                 MUSB_RXCSR_DMAMODE);
                        musb_writew(epio, MUSB_RXCSR, csr);
                }

                dmaengine_terminate_all(ux500_channel->dma_chan);
                channel->status = MUSB_DMA_STATUS_FREE;
        }
        return 0;
}

static void ux500_dma_controller_stop(struct ux500_dma_controller *controller)
{
        struct ux500_dma_channel *ux500_channel;
        struct dma_channel *channel;
        u8 ch_num;

        for (ch_num = 0; ch_num < UX500_MUSB_DMA_NUM_RX_TX_CHANNELS; ch_num++) {
                channel = &controller->rx_channel[ch_num].channel;
                ux500_channel = channel->private_data;

                ux500_dma_channel_release(channel);

                if (ux500_channel->dma_chan)
                        dma_release_channel(ux500_channel->dma_chan);
        }

        for (ch_num = 0; ch_num < UX500_MUSB_DMA_NUM_RX_TX_CHANNELS; ch_num++) {
                channel = &controller->tx_channel[ch_num].channel;
                ux500_channel = channel->private_data;

                ux500_dma_channel_release(channel);

                if (ux500_channel->dma_chan)
                        dma_release_channel(ux500_channel->dma_chan);
        }
}

static int ux500_dma_controller_start(struct ux500_dma_controller *controller)
{
        struct ux500_dma_channel *ux500_channel = NULL;
        struct musb *musb = controller->private_data;
        struct device *dev = musb->controller;
        struct musb_hdrc_platform_data *plat = dev_get_platdata(dev);
        struct ux500_musb_board_data *data;
        struct dma_channel *dma_channel = NULL;
        char **chan_names;
        u32 ch_num;
        u8 dir;
        u8 is_tx = 0;

        void **param_array;
        struct ux500_dma_channel *channel_array;
        dma_cap_mask_t mask;

        if (!plat) {
                dev_err(musb->controller, "No platform data\n");
                return -EINVAL;
        }

        data = plat->board_data;

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);

        /* Prepare the loop for RX channels */
        channel_array = controller->rx_channel;
        param_array = data ? data->dma_rx_param_array : NULL;
        chan_names = (char **)iep_chan_names;

        for (dir = 0; dir < 2; dir++) {
                for (ch_num = 0;
                     ch_num < UX500_MUSB_DMA_NUM_RX_TX_CHANNELS;
                     ch_num++) {
                        ux500_channel = &channel_array[ch_num];
                        ux500_channel->controller = controller;
                        ux500_channel->ch_num = ch_num;
                        ux500_channel->is_tx = is_tx;

                        dma_channel = &(ux500_channel->channel);
                        dma_channel->private_data = ux500_channel;
                        dma_channel->status = MUSB_DMA_STATUS_FREE;
                        dma_channel->max_len = SZ_16M;

                        ux500_channel->dma_chan =
                                dma_request_chan(dev, chan_names[ch_num]);

                        if (IS_ERR(ux500_channel->dma_chan))
                                ux500_channel->dma_chan =
                                        dma_request_channel(mask,
                                                            data ?
                                                            data->dma_filter :
                                                            NULL,
                                                            param_array ?
                                                            param_array[ch_num] :
                                                            NULL);

                        if (!ux500_channel->dma_chan) {
                                ERR("Dma pipe allocation error dir=%d ch=%d\n",
                                        dir, ch_num);

                                /* Release already allocated channels */
                                ux500_dma_controller_stop(controller);

                                return -EBUSY;
                        }

                }

                /* Prepare the loop for TX channels */
                channel_array = controller->tx_channel;
                param_array = data ? data->dma_tx_param_array : NULL;
                chan_names = (char **)oep_chan_names;
                is_tx = 1;
        }

        return 0;
}

void ux500_dma_controller_destroy(struct dma_controller *c)
{
        struct ux500_dma_controller *controller = container_of(c,
                        struct ux500_dma_controller, controller);

        ux500_dma_controller_stop(controller);
        kfree(controller);
}
EXPORT_SYMBOL_GPL(ux500_dma_controller_destroy);

struct dma_controller *
ux500_dma_controller_create(struct musb *musb, void __iomem *base)
{
        struct ux500_dma_controller *controller;
        struct platform_device *pdev = to_platform_device(musb->controller);
        struct resource *iomem;
        int ret;

        controller = kzalloc_obj(*controller);
        if (!controller)
                goto kzalloc_fail;

        controller->private_data = musb;

        /* Save physical address for DMA controller. */
        iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!iomem) {
                dev_err(musb->controller, "no memory resource defined\n");
                goto plat_get_fail;
        }

        controller->phy_base = (dma_addr_t) iomem->start;

        controller->controller.channel_alloc = ux500_dma_channel_allocate;
        controller->controller.channel_release = ux500_dma_channel_release;
        controller->controller.channel_program = ux500_dma_channel_program;
        controller->controller.channel_abort = ux500_dma_channel_abort;
        controller->controller.is_compatible = ux500_dma_is_compatible;

        ret = ux500_dma_controller_start(controller);
        if (ret)
                goto plat_get_fail;
        return &controller->controller;

plat_get_fail:
        kfree(controller);
kzalloc_fail:
        return NULL;
}
EXPORT_SYMBOL_GPL(ux500_dma_controller_create);