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Message-ID: <5374B34D.2060904@ti.com>
Date: Thu, 15 May 2014 15:30:05 +0300
From: Peter Ujfalusi <peter.ujfalusi@...com>
To: Sekhar Nori <nsekhar@...com>, <joelf@...com>
CC: <linux@....linux.org.uk>, <vinod.koul@...el.com>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-omap@...r.kernel.org>,
<devicetree@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<tony@...mide.com>, <bcousson@...libre.com>
Subject: Re: [PATCH v2 2/5] ARM: edma: Get IP information from HW when booting
with DT
Hi Sekhar,
On 05/15/2014 11:53 AM, Sekhar Nori wrote:
> Hi Peter,
>
> On Tuesday 13 May 2014 04:00 PM, Peter Ujfalusi wrote:
>> From CCCFG register of eDMA3 we can get all the needed information for the
>> driver about the IP:
>> Number of channels: NUM_DMACH
>> Number of regions: NUM_REGN
>> Number of slots (PaRAM sets): NUM_PAENTRY
>> Number of TC/EQ: NUM_EVQUE
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@...com>
>> ---
>> arch/arm/common/edma.c | 128 ++++++++++++++++++++++++++++++-------------------
>> 1 file changed, 79 insertions(+), 49 deletions(-)
>>
>> diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
>> index fade9ada81f8..1a98f3cd4cd9 100644
>> --- a/arch/arm/common/edma.c
>> +++ b/arch/arm/common/edma.c
>> @@ -102,7 +102,16 @@
>> #define PARM_OFFSET(param_no) (EDMA_PARM + ((param_no) << 5))
>>
>> #define EDMA_DCHMAP 0x0100 /* 64 registers */
>> -#define CHMAP_EXIST BIT(24)
>> +
>> +/* CCCFG register */
>> +#define GET_NUM_DMACH(x) (x & 0x7) /* bits 0-2 */
>> +#define GET_NUM_QDMACH(x) ((x & 0x70) >> 4) /* bits 4-6 */
>> +#define GET_NUM_INTCH(x) ((x & 0x700) >> 8) /* bits 8-10 */
>> +#define GET_NUM_PAENTRY(x) ((x & 0x7000) >> 12) /* bits 12-14 */
>> +#define GET_NUM_EVQUE(x) ((x & 0x70000) >> 16) /* bits 16-18 */
>> +#define GET_NUM_REGN(x) ((x & 0x300000) >> 20) /* bits 20-21 */
>> +#define CHMAP_EXIST BIT(24)
>> +#define MP_EXIST BIT(25)
>
> Of these new defines, you do not use GET_NUM_QDMACH(), GET_NUM_INTCH()
> and MP_EXIST (at least in this patch). Can you please get rid of them if
> not needed? May be its just me but its pretty annoying to search for a
> define only to find its never used :)
Sure, I can remove the ones we are not using in the code. I usually prefer to
have full description if the register even if we only use one bit from the
register.
>
>>
>> #define EDMA_MAX_DMACH 64
>> #define EDMA_MAX_PARAMENTRY 512
>> @@ -1415,6 +1424,68 @@ void edma_clear_event(unsigned channel)
>> }
>> EXPORT_SYMBOL(edma_clear_event);
>>
>> +static int edma_setup_info_from_hw(struct device *dev,
>> + struct edma_soc_info *pdata)
>> +{
>> + int i;
>> + u32 value, cccfg, n_tc;
>> + s8 (*queue_tc_map)[2], (*queue_priority_map)[2];
>> +
>> + /* Decode the eDMA3 configuration from CCCFG register */
>> + cccfg = edma_read(0, EDMA_CCCFG);
>
> You do not handle the second controller here, but its pretty straight
> forward to add that by passing the controller number to this function.
The second controller is not handled because in DT boot we only handle 1 cc as
far as I know. I don't know why, but this is how the DT support has been
written and used.
> I was wondering why we never read the hardware for this information
> before, and strangely enough cannot find any SoC where the CCCFG
> register does not publish this information correctly. I have tested on
> DA850, DA830, DM365, DM355 and DM6467.
Good question. I was also puzzled about this.
> Instead of keeping this specific to OF case, the code can be simplified
> much better if we read from hardware all the time. We can directly
> populate the equivalent variables in the internal structure 'struct
> edma' instead of populating them in 'struct edma_soc_info' and then
> copying then over.
Yes, we can switch the non DT boot to this mode as well, true. At first I
wanted to change code which I can test easily. For non DT boot I would need to
set up my old daVinci board ;)
>> +
>> + value = GET_NUM_DMACH(cccfg);
>> + pdata->n_channel = BIT(value + 1);
>> +
>> + value = GET_NUM_REGN(cccfg);
>> + pdata->n_region = BIT(value);
>> +
>> + value = GET_NUM_PAENTRY(cccfg);
>> + pdata->n_slot = BIT(value + 4);
>> +
>> + value = GET_NUM_EVQUE(cccfg);
>> + n_tc = value + 1;
>> +
>> + dev_dbg(dev, "eDMA3 HW configuration (cccfg: 0x%08x):\n", cccfg);
>> + dev_dbg(dev, "n_channel: %u\n", pdata->n_channel);
>> + dev_dbg(dev, "n_region: %u\n", pdata->n_region);
>> + dev_dbg(dev, "n_slot: %u\n", pdata->n_slot);
>> + dev_dbg(dev, "n_tc: %u\n", n_tc);
>> +
>
> [snip]
>
>> + pdata->n_cc = 1;
>> +
>> + queue_tc_map = devm_kzalloc(dev, (n_tc + 1) * sizeof(s8), GFP_KERNEL);
>> + if (!queue_tc_map)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < n_tc; i++) {
>> + queue_tc_map[i][0] = i;
>> + queue_tc_map[i][1] = i;
>> + }
>> + queue_tc_map[i][0] = -1;
>> + queue_tc_map[i][1] = -1;
>> +
>> + pdata->queue_tc_mapping = queue_tc_map;
>> +
>> + queue_priority_map = devm_kzalloc(dev, (n_tc + 1) * sizeof(s8),
>> + GFP_KERNEL);
>> + if (!queue_priority_map)
>> + return -ENOMEM;
>> +
>> + for (i = 0; i < n_tc; i++) {
>> + queue_priority_map[i][0] = i;
>> + queue_priority_map[i][1] = i;
>> + }
>> + queue_priority_map[i][0] = -1;
>> + queue_priority_map[i][1] = -1;
>> +
>> + pdata->queue_priority_mapping = queue_priority_map;
>> +
>> + pdata->default_queue = 0;
>
> This is part is not really setting up from hardware (rather falling back
> to some sane defaults for the DT case). Could you leave them in
> edma_of_parse_dt()?
Not really since the number of tc is not know as early as edma_of_parse_dt(),
we used to a magic number of 3 in place for n_tc previously.
We are doing similar things as previously done in edma_of_parse_dt() but with
'correct' number of tc.
>> @@ -1655,6 +1679,12 @@ static int edma_probe(struct platform_device *pdev)
>> if (IS_ERR(edmacc_regs_base[j]))
>> return PTR_ERR(edmacc_regs_base[j]);
>>
>> + if (node) {
>> + /* Get eDMA3 configuration from IP */
>> + ret = edma_setup_info_from_hw(dev, info[j]);
>> + if (ret)
>> + return ret;
>
> No need to do this only for the DT case, I think. Also, once we get rid
> of the edma_soc_info dependency, just pass edma_cc[] directly
>
> edma_setup_info_from_hw(dev, j, edma_cc[j]);
Yes, let's do this for DT and not DT boot as well.
I will keep the queue_tc_map and queue_priority_map setup in there I think to
be done in case of DT boot.
I'll try to craft v3 as soon as I can.
Thanks,
Péter
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