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Commit c6f82787 authored by Chuah, Kim Tatt's avatar Chuah, Kim Tatt Committed by Greg Kroah-Hartman
Browse files

dmaengine: hsu: Export hsu_dma_get_status() 



To allow other code to safely read DMA Channel Status Register (where
the register attribute for Channel Error, Descriptor Time Out &
Descriptor Done fields are read-clear), export hsu_dma_get_status().
hsu_dma_irq() is renamed to hsu_dma_do_irq() and requires Status
Register value to be passed in.

Signed-off-by: default avatarChuah, Kim Tatt <kim.tatt.chuah@intel.com>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d03516df

drivers/dma/hsu/hsu.c

+69 −21
Original line number Diff line number Diff line
@@ -126,28 +126,33 @@ static void hsu_dma_start_transfer(struct hsu_dma_chan *hsuc) 
	hsu_dma_start_channel(hsuc);

}



static u32 hsu_dma_chan_get_sr(struct hsu_dma_chan *hsuc)

{

	unsigned long flags;

	u32 sr;



	spin_lock_irqsave(&hsuc->vchan.lock, flags);

	sr = hsu_chan_readl(hsuc, HSU_CH_SR);

	spin_unlock_irqrestore(&hsuc->vchan.lock, flags);



	return sr & ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY);

}



irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr)

/*

 *      hsu_dma_get_status() - get DMA channel status

 *      @chip: HSUART DMA chip

 *      @nr: DMA channel number

 *      @status: pointer for DMA Channel Status Register value

 *

 *      Description:

 *      The function reads and clears the DMA Channel Status Register, checks

 *      if it was a timeout interrupt and returns a corresponding value.

 *

 *      Caller should provide a valid pointer for the DMA Channel Status

 *      Register value that will be returned in @status.

 *

 *      Return:

 *      1 for DMA timeout status, 0 for other DMA status, or error code for

 *      invalid parameters or no interrupt pending.

 */

int hsu_dma_get_status(struct hsu_dma_chip *chip, unsigned short nr,

		       u32 *status)

{

	struct hsu_dma_chan *hsuc;

	struct hsu_dma_desc *desc;

	unsigned long flags;

	u32 sr;



	/* Sanity check */

	if (nr >= chip->hsu->nr_channels)

		return IRQ_NONE;

		return -EINVAL;



	hsuc = &chip->hsu->chan[nr];
@@ -155,22 +160,65 @@ irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr) 
	 * No matter what situation, need read clear the IRQ status

	 * There is a bug, see Errata 5, HSD 2900918

	 */

	sr = hsu_dma_chan_get_sr(hsuc);

	spin_lock_irqsave(&hsuc->vchan.lock, flags);

	sr = hsu_chan_readl(hsuc, HSU_CH_SR);

	spin_unlock_irqrestore(&hsuc->vchan.lock, flags);



	/* Check if any interrupt is pending */

	sr &= ~(HSU_CH_SR_DESCE_ANY | HSU_CH_SR_CDESC_ANY);

	if (!sr)

		return IRQ_NONE;

		return -EIO;



	/* Timeout IRQ, need wait some time, see Errata 2 */

	if (sr & HSU_CH_SR_DESCTO_ANY)

		udelay(2);



	/*

	 * At this point, at least one of Descriptor Time Out, Channel Error

	 * or Descriptor Done bits must be set. Clear the Descriptor Time Out

	 * bits and if sr is still non-zero, it must be channel error or

	 * descriptor done which are higher priority than timeout and handled

	 * in hsu_dma_do_irq(). Else, it must be a timeout.

	 */

	sr &= ~HSU_CH_SR_DESCTO_ANY;

	if (!sr)

		return IRQ_HANDLED;



	*status = sr;



	return sr ? 0 : 1;

}

EXPORT_SYMBOL_GPL(hsu_dma_get_status);



/*

 *      hsu_dma_do_irq() - DMA interrupt handler

 *      @chip: HSUART DMA chip

 *      @nr: DMA channel number

 *      @status: Channel Status Register value

 *

 *      Description:

 *      This function handles Channel Error and Descriptor Done interrupts.

 *      This function should be called after determining that the DMA interrupt

 *      is not a normal timeout interrupt, ie. hsu_dma_get_status() returned 0.

 *

 *      Return:

 *      IRQ_NONE for invalid channel number, IRQ_HANDLED otherwise.

 */

irqreturn_t hsu_dma_do_irq(struct hsu_dma_chip *chip, unsigned short nr,

			   u32 status)

{

	struct hsu_dma_chan *hsuc;

	struct hsu_dma_desc *desc;

	unsigned long flags;



	/* Sanity check */

	if (nr >= chip->hsu->nr_channels)

		return IRQ_NONE;



	hsuc = &chip->hsu->chan[nr];



	spin_lock_irqsave(&hsuc->vchan.lock, flags);

	desc = hsuc->desc;

	if (desc) {

		if (sr & HSU_CH_SR_CHE) {

		if (status & HSU_CH_SR_CHE) {

			desc->status = DMA_ERROR;

		} else if (desc->active < desc->nents) {

			hsu_dma_start_channel(hsuc);
@@ -184,7 +232,7 @@ irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr) 


	return IRQ_HANDLED;

}

EXPORT_SYMBOL_GPL(hsu_dma_irq);

EXPORT_SYMBOL_GPL(hsu_dma_do_irq);



static struct hsu_dma_desc *hsu_dma_alloc_desc(unsigned int nents)

{

drivers/dma/hsu/pci.c

+9 −2
Original line number Diff line number Diff line
@@ -27,13 +27,20 @@ static irqreturn_t hsu_pci_irq(int irq, void *dev) 
{

	struct hsu_dma_chip *chip = dev;

	u32 dmaisr;

	u32 status;

	unsigned short i;

	irqreturn_t ret = IRQ_NONE;

	int err;



	dmaisr = readl(chip->regs + HSU_PCI_DMAISR);

	for (i = 0; i < chip->hsu->nr_channels; i++) {

		if (dmaisr & 0x1)

			ret |= hsu_dma_irq(chip, i);

		if (dmaisr & 0x1) {

			err = hsu_dma_get_status(chip, i, &status);

			if (err > 0)

				ret |= IRQ_HANDLED;

			else if (err == 0)

				ret |= hsu_dma_do_irq(chip, i, status);

		}

		dmaisr >>= 1;

	}

drivers/tty/serial/8250/8250_mid.c

+17 −5
Original line number Diff line number Diff line
@@ -97,12 +97,24 @@ static int dnv_handle_irq(struct uart_port *p) 
{

	struct mid8250 *mid = p->private_data;

	unsigned int fisr = serial_port_in(p, INTEL_MID_UART_DNV_FISR);

	u32 status;

	int ret = IRQ_NONE;



	if (fisr & BIT(2))

		ret |= hsu_dma_irq(&mid->dma_chip, 1);

	if (fisr & BIT(1))

		ret |= hsu_dma_irq(&mid->dma_chip, 0);

	int err;



	if (fisr & BIT(2)) {

		err = hsu_dma_get_status(&mid->dma_chip, 1, &status);

		if (err > 0)

			ret |= IRQ_HANDLED;

		else if (err == 0)

			ret |= hsu_dma_do_irq(&mid->dma_chip, 1, status);

	}

	if (fisr & BIT(1)) {

		err = hsu_dma_get_status(&mid->dma_chip, 0, &status);

		if (err > 0)

			ret |= IRQ_HANDLED;

		else if (err == 0)

			ret |= hsu_dma_do_irq(&mid->dma_chip, 0, status);

	}

	if (fisr & BIT(0))

		ret |= serial8250_handle_irq(p, serial_port_in(p, UART_IIR));

	return ret;

include/linux/dma/hsu.h

+11 −3
Original line number Diff line number Diff line
@@ -39,14 +39,22 @@ struct hsu_dma_chip { 


#if IS_ENABLED(CONFIG_HSU_DMA)

/* Export to the internal users */

irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip, unsigned short nr);

int hsu_dma_get_status(struct hsu_dma_chip *chip, unsigned short nr,

		       u32 *status);

irqreturn_t hsu_dma_do_irq(struct hsu_dma_chip *chip, unsigned short nr,

			   u32 status);



/* Export to the platform drivers */

int hsu_dma_probe(struct hsu_dma_chip *chip);

int hsu_dma_remove(struct hsu_dma_chip *chip);

#else

static inline irqreturn_t hsu_dma_irq(struct hsu_dma_chip *chip,

				      unsigned short nr)

static inline int hsu_dma_get_status(struct hsu_dma_chip *chip,

				     unsigned short nr, u32 *status)

{

	return 0;

}

static inline irqreturn_t hsu_dma_do_irq(struct hsu_dma_chip *chip,

					 unsigned short nr, u32 status)

{

	return IRQ_NONE;

}