Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> From ad2e1cd024ccf9144b6620cfe808893719db738f Mon Sep 17 00:00:00 2001
> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Date: Wed, 14 Apr 2010 16:26:45 +0300
> Subject: [PATCH] omap_hsmmc: improve interrupt synchronisation
>
> The following changes were needed:
> - do not use in_interrupt() because it will not work
> with threaded interrupts
>
> In addition, the following improvements were made:
> - ensure DMA is unmapped only after the final DMA interrupt
> - ensure a request is completed only after the final DMA interrupt
> - disable controller interrupts when a request is not in progress
> - remove the spin-lock protecting the start of a new request from
> an unexpected interrupt because the locking was complicated and
> a 'req_in_progress' flag suffices (since the spin-lock only defers
> the unexpected interrupts anyway)
> - instead use the spin-lock to protect the MMC interrupt handler
> from the DMA interrupt handler
> - remove the semaphore preventing DMA from being started while
> the previous DMA is still in progress - the other changes make that
> impossible, so it is now a BUG_ON condition
> - ensure the controller interrupt status is clear before exiting
> the interrrupt handler
>
> In general, these changes make the code safer but do not fix any specific
> bugs so backporting is not necessary.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
>
>
> Changes from version 1:
> - use a spin-lock to protect the MMC interrupt handler
> from the DMA interrupt handler
> - use do {} while loop instead of goto in omap_hsmmc_irq
>
> S Venkatraman's request to use omap_hsmmc_dma_cleanup(host, 0) in
> omap_hsmmc_dma_cb() was not done because the code was not
> sufficiently the same.
>
>
> drivers/mmc/host/omap_hsmmc.c | 262
> +++++++++++++++++++++--------------------
> 1 files changed, 134 insertions(+), 128 deletions(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index c0b5021..cc0272d 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -157,12 +157,10 @@ struct omap_hsmmc_host {
> */
> struct regulator *vcc;
> struct regulator *vcc_aux;
> - struct semaphore sem;
> struct work_struct mmc_carddetect_work;
> void __iomem *base;
> resource_size_t mapbase;
> spinlock_t irq_lock; /* Prevent races with irq handler
> */
> - unsigned long flags;
> unsigned int id;
> unsigned int dma_len;
> unsigned int dma_sg_idx;
> @@ -183,6 +181,7 @@ struct omap_hsmmc_host {
> int protect_card;
> int reqs_blocked;
> int use_reg;
> + int req_in_progress;
>
> struct omap_mmc_platform_data *pdata;
> };
> @@ -480,6 +479,27 @@ static void omap_hsmmc_stop_clock(struct
> omap_hsmmc_host *host)
> dev_dbg(mmc_dev(host->mmc), "MMC Clock is not stoped\n");
> }
>
> +static void omap_hsmmc_enable_irq(struct omap_hsmmc_host *host)
> +{
> + unsigned int irq_mask;
> +
> + if (host->use_dma)
> + irq_mask = INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE);
> + else
> + irq_mask = INT_EN_MASK;
> +
> + OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> + OMAP_HSMMC_WRITE(host->base, ISE, irq_mask);
> + OMAP_HSMMC_WRITE(host->base, IE, irq_mask);
> +}
> +
> +static void omap_hsmmc_disable_irq(struct omap_hsmmc_host *host)
> +{
> + OMAP_HSMMC_WRITE(host->base, ISE, 0);
> + OMAP_HSMMC_WRITE(host->base, IE, 0);
> + OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> +}
> +
> #ifdef CONFIG_PM
>
> /*
> @@ -548,9 +568,7 @@ static int omap_hsmmc_context_restore(struct
> omap_hsmmc_host *host)
> && time_before(jiffies, timeout))
> ;
>
> - OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> - OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
> - OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> + omap_hsmmc_disable_irq(host);
>
> /* Do not initialize card-specific things if the power is off */
> if (host->power_mode == MMC_POWER_OFF)
> @@ -653,6 +671,8 @@ static void send_init_stream(struct omap_hsmmc_host
> *host)
> return;
>
> disable_irq(host->irq);
> +
> + OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> OMAP_HSMMC_WRITE(host->base, CON,
> OMAP_HSMMC_READ(host->base, CON) | INIT_STREAM);
> OMAP_HSMMC_WRITE(host->base, CMD, INIT_STREAM_CMD);
> @@ -718,17 +738,7 @@ omap_hsmmc_start_command(struct omap_hsmmc_host *host,
> struct mmc_command *cmd,
> mmc_hostname(host->mmc), cmd->opcode, cmd->arg);
> host->cmd = cmd;
>
> - /*
> - * Clear status bits and enable interrupts
> - */
> - OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
> - OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
> -
> - if (host->use_dma)
> - OMAP_HSMMC_WRITE(host->base, IE,
> - INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE));
> - else
> - OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> + omap_hsmmc_enable_irq(host);
>
> host->response_busy = 0;
> if (cmd->flags & MMC_RSP_PRESENT) {
> @@ -762,13 +772,7 @@ omap_hsmmc_start_command(struct omap_hsmmc_host *host,
> struct mmc_command *cmd,
> if (host->use_dma)
> cmdreg |= DMA_EN;
>
> - /*
> - * In an interrupt context (i.e. STOP command), the spinlock is
> unlocked
> - * by the interrupt handler, otherwise (i.e. for a new request) it
> is
> - * unlocked here.
> - */
> - if (!in_interrupt())
> - spin_unlock_irqrestore(&host->irq_lock, host->flags);
> + host->req_in_progress = 1;
>
> OMAP_HSMMC_WRITE(host->base, ARG, cmd->arg);
> OMAP_HSMMC_WRITE(host->base, CMD, cmdreg);
> @@ -783,6 +787,23 @@ omap_hsmmc_get_dma_dir(struct omap_hsmmc_host *host,
> struct mmc_data *data)
> return DMA_FROM_DEVICE;
> }
>
> +static void omap_hsmmc_request_done(struct omap_hsmmc_host *host, struct
> mmc_request *mrq)
> +{
> + int dma_ch;
> +
> + spin_lock(&host->irq_lock);
> + host->req_in_progress = 0;
> + dma_ch = host->dma_ch;
> + spin_unlock(&host->irq_lock);
> +
> + omap_hsmmc_disable_irq(host);
> + /* Do not complete the request if DMA is still in progress */
> + if (mrq->data && host->use_dma && dma_ch != -1)
> + return;
> + host->mrq = NULL;
> + mmc_request_done(host->mmc, mrq);
> +}
> +
> /*
> * Notify the transfer complete to MMC core
> */
> @@ -799,25 +820,19 @@ omap_hsmmc_xfer_done(struct omap_hsmmc_host *host,
> struct mmc_data *data)
> return;
> }
>
> - host->mrq = NULL;
> - mmc_request_done(host->mmc, mrq);
> + omap_hsmmc_request_done(host, mrq);
> return;
> }
>
> host->data = NULL;
>
> - if (host->use_dma && host->dma_ch != -1)
> - dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
> - omap_hsmmc_get_dma_dir(host, data));
> -
> if (!data->error)
> data->bytes_xfered += data->blocks * (data->blksz);
> else
> data->bytes_xfered = 0;
>
> if (!data->stop) {
> - host->mrq = NULL;
> - mmc_request_done(host->mmc, data->mrq);
> + omap_hsmmc_request_done(host, data->mrq);
> return;
> }
> omap_hsmmc_start_command(host, data->stop, NULL);
> @@ -843,10 +858,8 @@ omap_hsmmc_cmd_done(struct omap_hsmmc_host *host,
> struct mmc_command *cmd)
> cmd->resp[0] = OMAP_HSMMC_READ(host->base, RSP10);
> }
> }
> - if ((host->data == NULL && !host->response_busy) || cmd->error) {
> - host->mrq = NULL;
> - mmc_request_done(host->mmc, cmd->mrq);
> - }
> + if ((host->data == NULL && !host->response_busy) || cmd->error)
> + omap_hsmmc_request_done(host, cmd->mrq);
> }
>
> /*
> @@ -854,14 +867,19 @@ omap_hsmmc_cmd_done(struct omap_hsmmc_host *host,
> struct mmc_command *cmd)
> */
> static void omap_hsmmc_dma_cleanup(struct omap_hsmmc_host *host, int errno)
> {
> + int dma_ch;
> +
> host->data->error = errno;
>
> - if (host->use_dma && host->dma_ch != -1) {
> + spin_lock(&host->irq_lock);
> + dma_ch = host->dma_ch;
> + host->dma_ch = -1;
> + spin_unlock(&host->irq_lock);
> +
> + if (host->use_dma && dma_ch != -1) {
> dma_unmap_sg(mmc_dev(host->mmc), host->data->sg,
> host->dma_len,
> omap_hsmmc_get_dma_dir(host, host->data));
> - omap_free_dma(host->dma_ch);
> - host->dma_ch = -1;
> - up(&host->sem);
> + omap_free_dma(dma_ch);
> }
> host->data = NULL;
> }
> @@ -923,28 +941,21 @@ static inline void
> omap_hsmmc_reset_controller_fsm(struct omap_hsmmc_host *host,
> __func__);
> }
>
> -/*
> - * MMC controller IRQ handler
> - */
> -static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
> +static void omap_hsmmc_do_irq(struct omap_hsmmc_host *host, int status)
> {
> - struct omap_hsmmc_host *host = dev_id;
> struct mmc_data *data;
> - int end_cmd = 0, end_trans = 0, status;
> -
> - spin_lock(&host->irq_lock);
> -
> - if (host->mrq == NULL) {
> - OMAP_HSMMC_WRITE(host->base, STAT,
> - OMAP_HSMMC_READ(host->base, STAT));
> - /* Flush posted write */
> - OMAP_HSMMC_READ(host->base, STAT);
> - spin_unlock(&host->irq_lock);
> - return IRQ_HANDLED;
> + int end_cmd = 0, end_trans = 0;
> +
> + if (!host->req_in_progress) {
> + do {
> + OMAP_HSMMC_WRITE(host->base, STAT, status);
> + /* Flush posted write */
> + status = OMAP_HSMMC_READ(host->base, STAT);
> + } while (status & INT_EN_MASK);
> + return;
> }
>
> data = host->data;
> - status = OMAP_HSMMC_READ(host->base, STAT);
> dev_dbg(mmc_dev(host->mmc), "IRQ Status is %x\n", status);
>
> if (status & ERR) {
> @@ -997,15 +1008,27 @@ static irqreturn_t omap_hsmmc_irq(int irq, void
> *dev_id)
> }
>
> OMAP_HSMMC_WRITE(host->base, STAT, status);
> - /* Flush posted write */
> - OMAP_HSMMC_READ(host->base, STAT);
>
> if (end_cmd || ((status & CC) && host->cmd))
> omap_hsmmc_cmd_done(host, host->cmd);
> if ((end_trans || (status & TC)) && host->mrq)
> omap_hsmmc_xfer_done(host, data);
> +}
>
> - spin_unlock(&host->irq_lock);
> +/*
> + * MMC controller IRQ handler
> + */
> +static irqreturn_t omap_hsmmc_irq(int irq, void *dev_id)
> +{
> + struct omap_hsmmc_host *host = dev_id;
> + int status;
> +
> + status = OMAP_HSMMC_READ(host->base, STAT);
> + do {
> + omap_hsmmc_do_irq(host, status);
> + /* Flush posted write */
> + status = OMAP_HSMMC_READ(host->base, STAT);
> + } while (status & INT_EN_MASK);
>
> return IRQ_HANDLED;
> }
> @@ -1205,31 +1228,47 @@ static void omap_hsmmc_config_dma_params(struct
> omap_hsmmc_host *host,
> /*
> * DMA call back function
> */
> -static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *data)
> +static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data)
> {
> - struct omap_hsmmc_host *host = data;
> + struct omap_hsmmc_host *host = cb_data;
> + struct mmc_data *data = host->mrq->data;
> + int dma_ch, req_in_progress;
>
> if (ch_status & OMAP2_DMA_MISALIGNED_ERR_IRQ)
> dev_dbg(mmc_dev(host->mmc), "MISALIGNED_ADRS_ERR\n");
>
> - if (host->dma_ch < 0)
> + spin_lock(&host->irq_lock);
> + if (host->dma_ch < 0) {
> + spin_unlock(&host->irq_lock);
> return;
> + }
>
> host->dma_sg_idx++;
> if (host->dma_sg_idx < host->dma_len) {
> /* Fire up the next transfer. */
> - omap_hsmmc_config_dma_params(host, host->data,
> - host->data->sg +
> host->dma_sg_idx);
> + omap_hsmmc_config_dma_params(host, data,
> + data->sg + host->dma_sg_idx);
> + spin_unlock(&host->irq_lock);
> return;
> }
>
> - omap_free_dma(host->dma_ch);
> + dma_unmap_sg(mmc_dev(host->mmc), data->sg, host->dma_len,
> + omap_hsmmc_get_dma_dir(host, data));
> +
> + req_in_progress = host->req_in_progress;
> + dma_ch = host->dma_ch;
> host->dma_ch = -1;
> - /*
> - * DMA Callback: run in interrupt context.
> - * mutex_unlock will throw a kernel warning if used.
> - */
> - up(&host->sem);
> + spin_unlock(&host->irq_lock);
> +
> + omap_free_dma(dma_ch);
> +
> + /* If DMA has finished after TC, complete the request */
> + if (!req_in_progress) {
> + struct mmc_request *mrq = host->mrq;
> +
> + host->mrq = NULL;
> + mmc_request_done(host->mmc, mrq);
> + }
> }
>
> /*
> @@ -1238,7 +1277,7 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status,
> void *data)
> static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host,
> struct mmc_request *req)
> {
> - int dma_ch = 0, ret = 0, err = 1, i;
> + int dma_ch = 0, ret = 0, i;
> struct mmc_data *data = req->data;
>
> /* Sanity check: all the SG entries must be aligned by block size. */
> @@ -1255,23 +1294,7 @@ static int omap_hsmmc_start_dma_transfer(struct
> omap_hsmmc_host *host,
> */
> return -EINVAL;
>
> - /*
> - * If for some reason the DMA transfer is still active,
> - * we wait for timeout period and free the dma
> - */
> - if (host->dma_ch != -1) {
> - set_current_state(TASK_UNINTERRUPTIBLE);
> - schedule_timeout(100);
> - if (down_trylock(&host->sem)) {
> - omap_free_dma(host->dma_ch);
> - host->dma_ch = -1;
> - up(&host->sem);
> - return err;
> - }
> - } else {
> - if (down_trylock(&host->sem))
> - return err;
> - }
> + BUG_ON(host->dma_ch != -1);
>
> ret = omap_request_dma(omap_hsmmc_get_dma_sync_dev(host, data),
> "MMC/SD", omap_hsmmc_dma_cb, host, &dma_ch);
> @@ -1371,37 +1394,27 @@ static void omap_hsmmc_request(struct mmc_host *mmc,
> struct mmc_request *req)
> struct omap_hsmmc_host *host = mmc_priv(mmc);
> int err;
>
> - /*
> - * Prevent races with the interrupt handler because of unexpected
> - * interrupts, but not if we are already in interrupt context i.e.
> - * retries.
> - */
> - if (!in_interrupt()) {
> - spin_lock_irqsave(&host->irq_lock, host->flags);
> - /*
> - * Protect the card from I/O if there is a possibility
> - * it can be removed.
> - */
> - if (host->protect_card) {
> - if (host->reqs_blocked < 3) {
> - /*
> - * Ensure the controller is left in a
> consistent
> - * state by resetting the command and data
> state
> - * machines.
> - */
> - omap_hsmmc_reset_controller_fsm(host, SRD);
> - omap_hsmmc_reset_controller_fsm(host, SRC);
> - host->reqs_blocked += 1;
> - }
> - req->cmd->error = -EBADF;
> - if (req->data)
> - req->data->error = -EBADF;
> - spin_unlock_irqrestore(&host->irq_lock,
> host->flags);
> - mmc_request_done(mmc, req);
> - return;
> - } else if (host->reqs_blocked)
> - host->reqs_blocked = 0;
> - }
> + BUG_ON(host->req_in_progress);
> + BUG_ON(host->dma_ch != -1);
> + if (host->protect_card) {
> + if (host->reqs_blocked < 3) {
> + /*
> + * Ensure the controller is left in a consistent
> + * state by resetting the command and data state
> + * machines.
> + */
> + omap_hsmmc_reset_controller_fsm(host, SRD);
> + omap_hsmmc_reset_controller_fsm(host, SRC);
> + host->reqs_blocked += 1;
> + }
> + req->cmd->error = -EBADF;
> + if (req->data)
> + req->data->error = -EBADF;
> + req->cmd->retries = 0;
> + mmc_request_done(mmc, req);
> + return;
> + } else if (host->reqs_blocked)
> + host->reqs_blocked = 0;
> WARN_ON(host->mrq != NULL);
> host->mrq = req;
> err = omap_hsmmc_prepare_data(host, req);
> @@ -1410,8 +1423,6 @@ static void omap_hsmmc_request(struct mmc_host *mmc,
> struct mmc_request *req)
> if (req->data)
> req->data->error = err;
> host->mrq = NULL;
> - if (!in_interrupt())
> - spin_unlock_irqrestore(&host->irq_lock,
> host->flags);
> mmc_request_done(mmc, req);
> return;
> }
> @@ -1980,7 +1991,6 @@ static int __init omap_hsmmc_probe(struct
> platform_device *pdev)
> mmc->f_min = 400000;
> mmc->f_max = 52000000;
>
> - sema_init(&host->sem, 1);
> spin_lock_init(&host->irq_lock);
>
> host->iclk = clk_get(&pdev->dev, "ick");
> @@ -2126,8 +2136,7 @@ static int __init omap_hsmmc_probe(struct
> platform_device *pdev)
> }
> }
>
> - OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
> - OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
> + omap_hsmmc_disable_irq(host);
>
> mmc_host_lazy_disable(host->mmc);
>
> @@ -2247,10 +2256,7 @@ static int omap_hsmmc_suspend(struct platform_device
> *pdev, pm_message_t state)
> mmc_host_enable(host->mmc);
> ret = mmc_suspend_host(host->mmc, state);
> if (ret == 0) {
> - OMAP_HSMMC_WRITE(host->base, ISE, 0);
> - OMAP_HSMMC_WRITE(host->base, IE, 0);
> -
> -
> + omap_hsmmc_disable_irq(host);
> OMAP_HSMMC_WRITE(host->base, HCTL,
> OMAP_HSMMC_READ(host->base, HCTL) & ~SDBP);
> mmc_host_disable(host->mmc);
> --
> 1.6.3.3
> --
This looks good and I don't have any other comments.
I have tested, on MMC and SD cards which I have,
a) Basic file read / write
b) boot with filesystem on ext3 partition on SD card
on OMAP3 and OMAP4 SDP.
So you can add,
Tested-by: Venkatraman S <svenkatr@xxxxxx>
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