Re: [PATCH 10/10] mtd: rawnand: gpmi: Implement exec_op

[Sascha Hauer <s.hauer@pengutronix.de>]

On Fri, Apr 05, 2019 at 12:07:40PM +0200, Sascha Hauer wrote:
> The gpmi driver performance suffers from nand operations being split
> in multiple small dma transfers. This has been forced by the nand layer
> in the former days, but now with exec_op we can use the controller as
> intended.
> 
> With this patch gpmi_nfc_exec_op becomes the main entry point to nand
> operations. Here all instructions are collected and chained as separate
> DMA transfers. In the end whole chain is fired and waited to be
> finished. gpmi_nfc_exec_op only does the hardware operations, bad block
> marker swapping and buffer scrambling is done by the callers. It's worth
> noting that the nand_*_op functions always take the buffer lengths for
> the data that the nand chip actually transfers. When doing BCH we have
> to calculate the net data size from the raw data size in some places.
> 
> This patch has been tested with 2048/64 and 2048/128 byte nand on
> i.MX6q. mtd_oobtest, mtd_subpagetest and mtd_speedtest run without
> errors. nandbiterrs, nandpagetest and nandsubpagetest userspace tests
> from mtdutils run without errors and UBIFS can successfully be mounted.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/dma/mxs-dma.c                      |    3 +
>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.c | 1104 ++++++++------------
>  drivers/mtd/nand/raw/gpmi-nand/gpmi-nand.h |   25 +-
>  3 files changed, 435 insertions(+), 697 deletions(-)
> 
> diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
> +
> +	dev_dbg(this->dev, "%s setup done\n", __func__);
> +
> +	if (nbufs > 1) {
> +		dev_err(this->dev, "Multiple data instructions not supported\n");
> +		ret = -EINVAL;
> +		goto unmap;
> +	}
> +
> +	if (this->bch) {
> +		writel(this->bch_flashlayout0,
> +		       this->resources.bch_regs + HW_BCH_FLASH0LAYOUT0);
> +		writel(this->bch_flashlayout1,
> +		       this->resources.bch_regs + HW_BCH_FLASH0LAYOUT1);
> +	}
> +
> +	if (this->bch && buf_read) {
> +		completion = &this->bch_done;
> +	} else {
> +		desc->callback = dma_irq_callback;
> +		desc->callback_param = this;
> +		completion = &this->dma_done;
> +	}
> +
> +	init_completion(completion);

This needs a fixup. The bch_done completion is not always used, still
the bch interrupt is always enabled and the interrupt handler calls
complete() on it. For some reason this works on i.MX6 but crashes on
i.MX28. We have to enable the bch interrupt only when needed.

Sascha

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