Subject: Re: [PATCH] fsl-rio: add support for mapping inbound windows

From: Martijn de Gouw <[email-masked]>
Date: Mon, 23 Jun 2014 15:57:23 +0200

On 06/18/2014 05:17 PM, Bounine, Alexandre wrote:
> On Friday, June 13, 2014 7:09 AM Martijn de Gouw [mailto:martijn.de.gouw@prodrive-
> technologies.com] wrote:
>
>> Add support for mapping and unmapping of inbound rapidio windows.
>>
>> Signed-off-by: Martijn de Gouw <[email-masked]>
>> ---
> ... skip ...
>
>> +
>> +int fsl_map_inb_mem(struct rio_mport *mport, dma_addr_t lstart,
>> +	u64 rstart, u32 size, u32 flags)
>> +{
>> +	struct rio_priv *priv = mport->priv;
>> +	u32 base_size;
>> +	unsigned int base_size_log;
>> +	u64 win_start, win_end;
>> +	u32 riwar;
>> +	int i;
>> +
>> +	base_size_log = __ilog2(size) + ((size & (size - 1)) != 0);
>> +	base_size = 1 << base_size_log;
>> +
>> +	for (i = 0; i < RIO_INB_ATMU_COUNT; i++) {
>> +		riwar = in_be32(&priv->inb_atmu_regs[i].riwar);
>> +		if ((riwar & RIWAR_ENABLE) == 0)
>> +			break;
>> +		/* check conflicting ranges */
>> +		win_start = ((u64)(in_be32(&priv->inb_atmu_regs[i].riwbar) & RIWBAR_BADD_MASK))
>> +			<< RIWBAR_BADD_VAL_SHIFT;
>> +		win_end = win_start + ((1 << ((riwar & RIWAR_SIZE_MASK) + 1)) - 1);
>> +		if (rstart < win_end && (rstart + size) > win_start)
>> +			return -EINVAL;
>> +	}
>
> It looks like the check for conflicting ranges assumes sequential mapping requests only.
> This check will be missed if ATMU windows are dynamically mapped/unmapped out-of-order.
> Because the unmap callback is implemented please consider possibility of using ATMU windows
> in any order.
>

You are correct. I'll send a new patch which first check all enabled 
windows for conflicts, before is searches for a free ATMU.

-- 
Martijn de Gouw
Engineer
Prodrive Technologies B.V.
Mobile: +31 63 17 76 161
Phone:  +31 40 26 76 200