RE: [PATCH v5] spi: spi-mem: Adjust op len based on message/transfer size limitations

[Chuanhua Han]

> -----Original Message-----
> From: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
> Sent: 2018年8月30日 16:47
> To: Chuanhua Han <chuanhua.han@xxxxxxx>
> Cc: broonie@xxxxxxxxxx; linux-spi@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5] spi: spi-mem: Adjust op len based on message/transfer
> size limitations
> 
> Hi Chuanhua,
> 
> On Thu, 30 Aug 2018 16:43:24 +0800
> Chuanhua Han <chuanhua.han@xxxxxxx> wrote:
> 
> > We need that to adjust the len of the 2nd transfer (called data in
> > spi-mem) if it's too long to fit in a SPI message or SPI transfer.
> 
> You already sent this email a few days back. Please wait a bit before sending it
> again. And when you do so and nothing changed in the patch please use the
> [PATCH RESEND vX] prefix and explain why you resend it.
I have modified the patch for the comment you mentioned last time. Do you need any other modification？
> 
> Thanks,
> 
> Boris
> 
> >
> > Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI
> > memory controllers")
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Chuanhua Han <chuanhua.han@xxxxxxx>
> > Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
> > ---
> > Changes in v5:
> >   -Add the validation check after the op->data.nbytes assignment
> >   -Assign the "len" variable after defining it
> >   -Remove the brackets on both sides of "opt-> data.nbytes"
> > Changes in v4:
> >   -Rename variable name "opcode_addr_dummy_sum" to "len"
> >   -The comparison of "spi_max_message_size(mem->spi)" and "len" was
> removed
> >   -Adjust their order when comparing the sizes of
> "spi_max_message_size(mem->spi)" and "len"
> >   -Changing the "unsigned long" type in the code to "size_t"
> > Changes in v3:
> >   -Rename variable name "val" to "opcode_addr_dummy_sum"
> >   -Place the legitimacy of the transfer size(i.e.,
> > "spi_max_message_size(mem->spi)" and
> > "opcode_addr_dummy_sum") into "if (! ctlr - > mem_ops | |! ctlr->
> mem_ops->exec_op) {"
> > structure and add "spi_max_transfer_size(mem->spi) and
> opcode_addr_dummy_sum"
> >   -Adjust the formatting alignment of the code
> >   -"(unsigned long)op->data.nbytes" was modified to "(unsigned
> long)(op->data.nbytes)"
> > Changes in v2:
> >   -Place the adjusted transfer bytes code in spi_mem_adjust_op_size()
> > and  check
> > spi_max_message_size(mem->spi) value before subtracting opcode, addr and
> dummy bytes
> >   -Change the code from fsl-espi controller to generic code(The
> > adjustment of spi transmission length was originally modified in the
> > "drivers/spi/spi-fsl-espi.c" file, and now the adjustment of transfer
> > length is made in the "drivers/spi/spi-mem.c" file)
> >
> >  drivers/spi/spi-mem.c | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >
> > diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c index
> > e43842c..eb72dba 100644
> > --- a/drivers/spi/spi-mem.c
> > +++ b/drivers/spi/spi-mem.c
> > @@ -346,10 +346,25 @@ EXPORT_SYMBOL_GPL(spi_mem_get_name);
> >  int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op
> > *op)  {
> >  	struct spi_controller *ctlr = mem->spi->controller;
> > +	size_t len;
> > +
> > +	len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
> >
> >  	if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
> >  		return ctlr->mem_ops->adjust_op_size(mem, op);
> >
> > +	if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
> > +		if (len > spi_max_transfer_size(mem->spi))
> > +			return -EINVAL;
> > +
> > +		op->data.nbytes = min3((size_t)op->data.nbytes,
> > +				       spi_max_transfer_size(mem->spi),
> > +				       spi_max_message_size(mem->spi) -
> > +				       len);
> > +		if (!op->data.nbytes)
> > +			return -EINVAL;
> > +	}
> > +
> >  	return 0;
> >  }
> >  EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);