Re: [PATCH 09/12] ahci: Introduce ahci_set_em_messages()

[Jeff Garzik <jeff@garzik.org>]

On 03/02/2010 04:18 PM, Sergei Shtylyov wrote:
> Hello.
>
> Anton Vorontsov wrote:
>
>> Factor out some ahci_em_messages handling code from ahci_init_one().
>> We would like to reuse it for non-PCI devices.
>>
>> Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
>> ---
>> drivers/ata/ahci.c | 41 ++++++++++++++++++++++++-----------------
>> 1 files changed, 24 insertions(+), 17 deletions(-)
>>
>> diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
>> index 18443e9..6694b17 100644
>> --- a/drivers/ata/ahci.c
>> +++ b/drivers/ata/ahci.c
>> @@ -3040,6 +3040,29 @@ static inline void
>> ahci_gtf_filter_workaround(struct ata_host *host)
>> {}
>> #endif
>>
>> +static void ahci_set_em_messages(struct ahci_host_priv *hpriv,
>> + struct ata_port_info *pi)
>> +{
>> + u8 messages;
>> + void __iomem *mmio = hpriv->mmio;
>> + u32 em_loc = readl(mmio + HOST_EM_LOC);
>> + u32 em_ctl = readl(mmio + HOST_EM_CTL);
>> +
>> + if (!ahci_em_messages || !(hpriv->cap & HOST_CAP_EMS))
>> + return;
>> +
>> + messages = (em_ctl & EM_CTRL_MSG_TYPE) >> 16;
>> +
>> + /* we only support LED message type right now */
>> + if ((messages & 0x01) && (ahci_em_messages == 1)) {
>> + /* store em_loc */
>> + hpriv->em_loc = ((em_loc >> 16) * 4);
>
> Could drop unneeded parens, while at it...

While not strictly necessary, parens often help with readability.  I 
think the above code looks fine as-is.  If the reader has to waste a few 
seconds recalling C's operator precedence, that detracts from the easy 
reading of the code.  Not everyone is like me and has worked on a C 
compiler, you know ;-)

	Jeff