Re: [PATCH 2/5] drm/msm/dsi: add implementation for helper functions

[Sibi S <sibis-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>]

Hi Jordan,
Thanks for the review. Will incorporate the suggested changes in v2.

On 03/12/2018 08:43 PM, Jordan Crouse wrote:
> On Mon, Mar 12, 2018 at 06:53:11PM +0530, Sibi S wrote:
>> Add dsi host helper function implementation for DSI v2
>> and DSI 6G 1.x controllers
>>
>> Signed-off-by: Sibi S <sibis@codeaurora.org>
>> ---
>>   drivers/gpu/drm/msm/dsi/dsi.h      |  15 +++
>>   drivers/gpu/drm/msm/dsi/dsi_cfg.c  |  44 +++++--
>>   drivers/gpu/drm/msm/dsi/dsi_host.c | 250 ++++++++++++++++++++++++++++++++++++-
>>   3 files changed, 298 insertions(+), 11 deletions(-)
> 
> <snip>
>>   static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
>>   {
>>   	struct drm_display_mode *mode = msm_host->mode;
>> @@ -1008,6 +1161,59 @@ static void dsi_wait4video_eng_busy(struct msm_dsi_host *msm_host)
>>   	}
>>   }
>>   
>> +int dsi_tx_buf_alloc_6g(struct msm_dsi_host *msm_host, int size)
>> +{
>> +	struct drm_device *dev = msm_host->dev;
>> +	struct msm_drm_private *priv = dev->dev_private;
>> +	int ret;
>> +	uint64_t iova;
>> +
>> +	msm_host->tx_gem_obj = msm_gem_new(dev, size, MSM_BO_UNCACHED);
>> +	if (IS_ERR(msm_host->tx_gem_obj)) {
>> +		ret = PTR_ERR(msm_host->tx_gem_obj);
>> +		pr_err("%s: failed to allocate gem, %d\n",
>> +			__func__, ret);
>> +		msm_host->tx_gem_obj = NULL;
>> +		return ret;
>> +	}
>> +
>> +	ret = msm_gem_get_iova(msm_host->tx_gem_obj,
>> +			priv->kms->aspace, &iova);
>> +	mutex_unlock(&dev->struct_mutex);
>> +	if (ret) {
>> +		pr_err("%s: failed to get iova, %d\n", __func__, ret);
>> +		return ret;
>> +	}
>> +
>> +	if (iova & 0x07) {
>> +		pr_err("%s: buf NOT 8 bytes aligned\n", __func__);
>> +		return -EINVAL;
>> +	}
> 
> This is impossible - new allocations will always be page aligned.
> 

Its always good to review and remove older code paths :).
Sure will remove this check.

>> +	msm_host->tx_size = msm_host->tx_gem_obj->size;
>> +
>> +	return 0;
>> +}
>> +
>> +int dsi_tx_buf_alloc_v2(struct msm_dsi_host *msm_host, int size)
>> +{
>> +	struct drm_device *dev = msm_host->dev;
>> +	int ret;
>> +
>> +	msm_host->tx_buf = dma_alloc_coherent(dev->dev, size,
>> +					&msm_host->tx_buf_paddr, GFP_KERNEL);
>> +	if (!msm_host->tx_buf) {
>> +		ret = -ENOMEM;
>> +		pr_err("%s: failed to allocate tx buf, %d\n",
>> +			__func__, ret);
> 
> You don't need to print ret here, it isn't a mystery what it is.  In fact, you
> probably don't need to print anything here at all because dma_alloc_coherent
> should be pretty noisy when it fails.
> 
>> +		return ret;
> 
> This can just be return -ENOMEM and you can lose 'ret'.
> 

yep makes sense, will replace it.

>> +	}
>> +
>> +	msm_host->tx_size = size;
>> +
>> +	return 0;
>> +}
>> +
>>   /* dsi_cmd */
>>   static int dsi_tx_buf_alloc(struct msm_dsi_host *msm_host, int size)
>>   {
>> @@ -1072,6 +1278,21 @@ static void dsi_tx_buf_free(struct msm_dsi_host *msm_host)
>>   			msm_host->tx_buf_paddr);
>>   }
>>   
>> +void *dsi_tx_buf_get_6g(struct msm_dsi_host *msm_host)
>> +{
>> +	return msm_gem_get_vaddr(msm_host->tx_gem_obj);
>> +}
>> +
>> +void *dsi_tx_buf_get_v2(struct msm_dsi_host *msm_host)
>> +{
>> +	return msm_host->tx_buf;
>> +}
>> +
>> +void dsi_tx_buf_put_6g(struct msm_dsi_host *msm_host)
>> +{
>> +	msm_gem_put_vaddr(msm_host->tx_gem_obj);
>> +}
>> +
>>   /*
>>    * prepare cmd buffer to be txed
>>    */
>> @@ -1173,6 +1394,31 @@ static int dsi_long_read_resp(u8 *buf, const struct mipi_dsi_msg *msg)
>>   	return msg->rx_len;
>>   }
>>   
>> +int dsi_dma_base_get_6g(struct msm_dsi_host *msm_host, uint64_t *dma_base)
>> +{
>> +	struct drm_device *dev = msm_host->dev;
>> +	struct msm_drm_private *priv = dev->dev_private;
>> +	uint64_t **iova;
>> +	int ret;
>> +
>> +	if (!dma_base)
>> +		return -EINVAL;
>> +
>> +	iova = &dma_base;
> 
> This is a convoluted way of passing in the pointer and I doubt even the compiler
> can see through it.
> 
>> +	ret = msm_gem_get_iova(msm_host->tx_gem_obj,
>> +				priv->kms->aspace, *iova);
> 
> ret = msm_gem_get_iova(msm_host->tx_gem_obj, priv->kms->aspace, dma_base);
> 
> Easy, safe effective
> 
>> +	return ret;
> 
> If you put a return on the front of the msm_gem_get_iova you can eliminate the
> need for 'ret'.
> 

ok will do just that.

> Jordan
> 

-- 
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc, is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project
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