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OMAP3: McBSP: Change the way how the FIFO is handled

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Use the actual FIFO size in words as buffer_size on OMAP3.
Change the threshold configuration to use 1 based numbering, when
specifying the allowed threshold maximum or the McBSP threshold value.
Set the default maximum threshold to (buffer_size - 0x10) intialy.
>From users of McBSP, now it is expected to use this method.
Asking for threshold 1 means that the value written to threshold registers
are going to be 0, which means 1 word threshold.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Mark Brown <broonie@opensource.wolsfonmicro.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
This commit is contained in:
Peter Ujfalusi
2010-06-03 07:39:33 +03:00
committed by Liam Girdwood
parent 0acce82b3d
commit 451fd82dc1
2 changed files with 25 additions and 15 deletions
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30
arch/arm/plat-omap/mcbsp.c
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@@ -481,9 +481,9 @@ int omap_st_is_enabled(unsigned int id)
EXPORT_SYMBOL(omap_st_is_enabled);
/*
* omap_mcbsp_set_tx_threshold configures how to deal
* with transmit threshold. the threshold value and handler can be
* configure in here.
* omap_mcbsp_set_rx_threshold configures the transmit threshold in words.
* The threshold parameter is 1 based, and it is converted (threshold - 1)
* for the THRSH2 register.
*/
void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
{
@@ -498,14 +498,15 @@ void omap_mcbsp_set_tx_threshold(unsigned int id, u16 threshold)
}
mcbsp = id_to_mcbsp_ptr(id);
MCBSP_WRITE(mcbsp, THRSH2, threshold);
if (threshold && threshold <= mcbsp->max_tx_thres)
MCBSP_WRITE(mcbsp, THRSH2, threshold - 1);
}
EXPORT_SYMBOL(omap_mcbsp_set_tx_threshold);
/*
* omap_mcbsp_set_rx_threshold configures how to deal
* with receive threshold. the threshold value and handler can be
* configure in here.
* omap_mcbsp_set_rx_threshold configures the receive threshold in words.
* The threshold parameter is 1 based, and it is converted (threshold - 1)
* for the THRSH1 register.
*/
void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
{
@@ -520,7 +521,8 @@ void omap_mcbsp_set_rx_threshold(unsigned int id, u16 threshold)
}
mcbsp = id_to_mcbsp_ptr(id);
MCBSP_WRITE(mcbsp, THRSH1, threshold);
if (threshold && threshold <= mcbsp->max_rx_thres)
MCBSP_WRITE(mcbsp, THRSH1, threshold - 1);
}
EXPORT_SYMBOL(omap_mcbsp_set_rx_threshold);
@@ -1697,8 +1699,16 @@ static inline void __devinit omap34xx_device_init(struct omap_mcbsp *mcbsp)
{
mcbsp->dma_op_mode = MCBSP_DMA_MODE_ELEMENT;
if (cpu_is_omap34xx()) {
mcbsp->max_tx_thres = max_thres(mcbsp);
mcbsp->max_rx_thres = max_thres(mcbsp);
/*
* Initially configure the maximum thresholds to a safe value.
* The McBSP FIFO usage with these values should not go under
* 16 locations.
* If the whole FIFO without safety buffer is used, than there
* is a possibility that the DMA will be not able to push the
* new data on time, causing channel shifts in runtime.
*/
mcbsp->max_tx_thres = max_thres(mcbsp) - 0x10;
mcbsp->max_rx_thres = max_thres(mcbsp) - 0x10;
/*
* REVISIT: Set dmap_op_mode to THRESHOLD as default
* for mcbsp2 instances.