On 24-11-24, 16:48, Sasha Finkelstein via B4 Relay wrote:
> From: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
>
> The ADMAC attached to the AOP has complex power sequencing, and is
> power gated when the probe callback runs. Move the register reads
> to other functions, where we can guarantee that the hardware is
> switched on.
So looking at the driver, there is code to turn power, so what ensures
that power is up while we are in alloc callback
>
> Fixes: 568aa6dd641f ("dmaengine: apple-admac: Allocate cache SRAM to channels")
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
> ---
> drivers/dma/apple-admac.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c
> index 9588773dd2eb670a2f6115fdaef39a0e88248015..037ec38730cf980eee11ebb8ec17be7623879cf8 100644
> --- a/drivers/dma/apple-admac.c
> +++ b/drivers/dma/apple-admac.c
> @@ -153,6 +153,8 @@ static int admac_alloc_sram_carveout(struct admac_data *ad,
> {
> struct admac_sram *sram;
> int i, ret = 0, nblocks;
Empty line before this please
> + ad->txcache.size = readl_relaxed(ad->base + REG_TX_SRAM_SIZE);
> + ad->rxcache.size = readl_relaxed(ad->base + REG_RX_SRAM_SIZE);
>
> if (dir == DMA_MEM_TO_DEV)
> sram = &ad->txcache;
> @@ -912,12 +914,7 @@ static int admac_probe(struct platform_device *pdev)
> goto free_irq;
> }
>
> - ad->txcache.size = readl_relaxed(ad->base + REG_TX_SRAM_SIZE);
> - ad->rxcache.size = readl_relaxed(ad->base + REG_RX_SRAM_SIZE);
> -
> dev_info(&pdev->dev, "Audio DMA Controller\n");
> - dev_info(&pdev->dev, "imprint %x TX cache %u RX cache %u\n",
> - readl_relaxed(ad->base + REG_IMPRINT), ad->txcache.size, ad->rxcache.size);
>
> return 0;
>
>
> ---
> base-commit: 9f16d5e6f220661f73b36a4be1b21575651d8833
> change-id: 20241124-admac-power-7f32c2a1850a
>
--
~Vinod
