Re: [PATCH 2/4] i2c: mediatek: Support DMA mask range over 33-bits

[Qii Wang <qii.wang@mediatek.com>]

On Wed, 2020-07-22 at 17:38 +0200, Matthias Brugger wrote:
> 
> On 22/07/2020 14:31, Qii Wang wrote:
> > Replace 'support_33bits with 'dma_max_support' for DMA mask
> > operation, and replace 'mtk_i2c_set_4g_mode' with 'upper_32_bits'.
> 
> Please explain more in detail what you are doing and how this fits to the way 
> the HW works.
> 

As Yingjoe sir said, Newer MTK chip support more than 8GB of dram, and
the register TX/RX_4G_MODE of APDMA has added corresponding bit to
support.So we Replace support_33bits with more general dma_max_support.I
will modify the title and commit as :
i2c: mediatek: Add access to more than 8GB dram in i2c driver
Newer MTK chip support more than 8GB of dram. Replace support_33bits
with more general dma_max_support and remove mtk_i2c_set_4g_mode.

> > 
> > Signed-off-by: Qii Wang <qii.wang@mediatek.com>
> > ---
> >   drivers/i2c/busses/i2c-mt65xx.c | 37 +++++++++++++++++--------------------
> >   1 file changed, 17 insertions(+), 20 deletions(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> > index e6b984a..e475877 100644
> > --- a/drivers/i2c/busses/i2c-mt65xx.c
> > +++ b/drivers/i2c/busses/i2c-mt65xx.c
> > @@ -209,6 +209,7 @@ struct mtk_i2c_compatible {
> >   	unsigned char dma_sync: 1;
> >   	unsigned char ltiming_adjust: 1;
> >   	unsigned char apdma_sync: 1;
> > +	unsigned char max_dma_support;
> >   };
> >   
> >   struct mtk_i2c_ac_timing {
> > @@ -311,11 +312,11 @@ struct i2c_spec_values {
> >   	.dcm = 1,
> >   	.auto_restart = 1,
> >   	.aux_len_reg = 1,
> > -	.support_33bits = 1,
> >   	.timing_adjust = 1,
> >   	.dma_sync = 0,
> >   	.ltiming_adjust = 0,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 33,
> >   };
> >   
> >   static const struct mtk_i2c_compatible mt6577_compat = {
> > @@ -325,11 +326,11 @@ struct i2c_spec_values {
> >   	.dcm = 1,
> >   	.auto_restart = 0,
> >   	.aux_len_reg = 0,
> > -	.support_33bits = 0,
> >   	.timing_adjust = 0,
> >   	.dma_sync = 0,
> >   	.ltiming_adjust = 0,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 32,
> >   };
> >   
> >   static const struct mtk_i2c_compatible mt6589_compat = {
> > @@ -339,11 +340,11 @@ struct i2c_spec_values {
> >   	.dcm = 0,
> >   	.auto_restart = 0,
> >   	.aux_len_reg = 0,
> > -	.support_33bits = 0,
> >   	.timing_adjust = 0,
> >   	.dma_sync = 0,
> >   	.ltiming_adjust = 0,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 32,
> >   };
> >   
> >   static const struct mtk_i2c_compatible mt7622_compat = {
> > @@ -353,11 +354,11 @@ struct i2c_spec_values {
> >   	.dcm = 1,
> >   	.auto_restart = 1,
> >   	.aux_len_reg = 1,
> > -	.support_33bits = 0,
> >   	.timing_adjust = 0,
> >   	.dma_sync = 0,
> >   	.ltiming_adjust = 0,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 32,
> >   };
> >   
> >   static const struct mtk_i2c_compatible mt8173_compat = {
> > @@ -366,11 +367,11 @@ struct i2c_spec_values {
> >   	.dcm = 1,
> >   	.auto_restart = 1,
> >   	.aux_len_reg = 1,
> > -	.support_33bits = 1,
> >   	.timing_adjust = 0,
> >   	.dma_sync = 0,
> >   	.ltiming_adjust = 0,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 33,
> >   };
> >   
> >   static const struct mtk_i2c_compatible mt8183_compat = {
> > @@ -380,11 +381,11 @@ struct i2c_spec_values {
> >   	.dcm = 0,
> >   	.auto_restart = 1,
> >   	.aux_len_reg = 1,
> > -	.support_33bits = 1,
> >   	.timing_adjust = 1,
> >   	.dma_sync = 1,
> >   	.ltiming_adjust = 1,
> >   	.apdma_sync = 0,
> > +	.max_dma_support = 33,
> >   };
> >   
> >   static const struct of_device_id mtk_i2c_of_match[] = {
> > @@ -796,11 +797,6 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
> >   	return 0;
> >   }
> >   
> > -static inline u32 mtk_i2c_set_4g_mode(dma_addr_t addr)
> > -{
> > -	return (addr & BIT_ULL(32)) ? I2C_DMA_4G_MODE : I2C_DMA_CLR_FLAG;
> 
> I2C_DMA_4G_MODE define could now be deleted as well.
> 
> Regards,
> Matthias
> 
> > -}
> > -
> >   static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> >   			       int num, int left_num)
> >   {
> > @@ -885,8 +881,8 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> >   			return -ENOMEM;
> >   		}
> >   
> > -		if (i2c->dev_comp->support_33bits) {
> > -			reg_4g_mode = mtk_i2c_set_4g_mode(rpaddr);
> > +		if (i2c->dev_comp->max_dma_support > 32) {
> > +			reg_4g_mode = upper_32_bits(rpaddr);
> >   			writel(reg_4g_mode, i2c->pdmabase + OFFSET_RX_4G_MODE);
> >   		}
> >   
> > @@ -908,8 +904,8 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> >   			return -ENOMEM;
> >   		}
> >   
> > -		if (i2c->dev_comp->support_33bits) {
> > -			reg_4g_mode = mtk_i2c_set_4g_mode(wpaddr);
> > +		if (i2c->dev_comp->max_dma_support > 32) {
> > +			reg_4g_mode = upper_32_bits(wpaddr);
> >   			writel(reg_4g_mode, i2c->pdmabase + OFFSET_TX_4G_MODE);
> >   		}
> >   
> > @@ -954,11 +950,11 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> >   			return -ENOMEM;
> >   		}
> >   
> > -		if (i2c->dev_comp->support_33bits) {
> > -			reg_4g_mode = mtk_i2c_set_4g_mode(wpaddr);
> > +		if (i2c->dev_comp->max_dma_support > 32) {
> > +			reg_4g_mode = upper_32_bits(wpaddr);
> >   			writel(reg_4g_mode, i2c->pdmabase + OFFSET_TX_4G_MODE);
> >   
> > -			reg_4g_mode = mtk_i2c_set_4g_mode(rpaddr);
> > +			reg_4g_mode = upper_32_bits(rpaddr);
> >   			writel(reg_4g_mode, i2c->pdmabase + OFFSET_RX_4G_MODE);
> >   		}
> >   
> > @@ -1232,8 +1228,9 @@ static int mtk_i2c_probe(struct platform_device *pdev)
> >   		return -EINVAL;
> >   	}
> >   
> > -	if (i2c->dev_comp->support_33bits) {
> > -		ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(33));
> > +	if (i2c->dev_comp->max_dma_support > 32) {
> > +		ret = dma_set_mask(&pdev->dev,
> > +				DMA_BIT_MASK(i2c->dev_comp->max_dma_support));
> >   		if (ret) {
> >   			dev_err(&pdev->dev, "dma_set_mask return error.\n");
> >   			return ret;
> >