On 04/29/2013 11:57 AM, Jassi Brar wrote:
> On 29 April 2013 22:14, Suman Anna <s-a...@ti.com> wrote:
>> On 04/27/2013 01:14 PM, jassisinghb...@gmail.com wrote:
>>> From: Jassi Brar <jaswinder.si...@linaro.org>
>>> Signed-off-by: Jassi Brar <jaswinder.si...@linaro.org>
>>> ---
>>> drivers/cpufreq/highbank-cpufreq.c | 22 +++-
>>> drivers/mailbox/Makefile | 2 +-
>>> drivers/mailbox/{pl320-ipc.c => pl320.c} | 194
>>> ++++++++++++++++--------------
>>> include/linux/pl320-ipc.h | 17 ---
>>> 4 files changed, 125 insertions(+), 110 deletions(-)
>>> rename drivers/mailbox/{pl320-ipc.c => pl320.c} (51%)
>>> delete mode 100644 include/linux/pl320-ipc.h
>>>
>>> diff --git a/drivers/cpufreq/highbank-cpufreq.c
>>> b/drivers/cpufreq/highbank-cpufreq.c
>>> index 3118b87..5c057e0 100644
>>> --- a/drivers/cpufreq/highbank-cpufreq.c
>>> +++ b/drivers/cpufreq/highbank-cpufreq.c
>>> @@ -19,7 +19,7 @@
>>> #include <linux/cpu.h>
>>> #include <linux/err.h>
>>> #include <linux/of.h>
>>> -#include <linux/pl320-ipc.h>
>>> +#include <linux/mailbox_client.h>
>>> #include <linux/platform_device.h>
>>>
>>> #define HB_CPUFREQ_CHANGE_NOTE 0x80000001
>>> @@ -29,8 +29,26 @@
>>> static int hb_voltage_change(unsigned int freq)
>>> {
>>> u32 msg[HB_CPUFREQ_IPC_LEN] = {HB_CPUFREQ_CHANGE_NOTE, freq /
>>> 1000000};
>>> + struct ipc_client cl;
>>> + int ret = -ETIMEDOUT;
>>> + void *chan;
>>>
>>> - return pl320_ipc_transmit(msg);
>>> + cl.rxcb = NULL;
>>> + cl.txcb = NULL;
>>> + cl.tx_block = true;
>>> + cl.tx_tout = 1000; /* 1 sec */
>>> + cl.cntlr_data = NULL;
>>> + cl.knows_txdone = false;
>>> + cl.chan_name = "pl320:A9_to_M3";
>>> +
>>> + chan = ipc_request_channel(&cl);
>>> +
>>> + if (ipc_send_message(chan, (void *)msg))
>>> + ret = msg[1]; /* PL320 updates buffer with FIFO after ACK */
>>> +
>>> + ipc_free_channel(chan);
>>
>> I think I understand why you have done this, but do you really want to
>> request and free every time in the highbank cpufreq driver?
>>
> Exactly my aim - make the API light enough to enable the client to
> use-and-throw. And also because the channel are exclusively assigned,
> acquire a channel only for as long as you need it.
Do you have any numbers on the performance impact? Our cpufreq
transition throughput is bad enough without adding additional delays.
--Mark Langsdorf
Calxeda, Inc.
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