Re: [PATCH] drm/rockchip: vop: do axi reset in vop initial time

On 06/01/2016 11:19 PM, Thierry Reding wrote:

On Wed, Jun 01, 2016 at 05:19:12PM +0800, Yakir Yang wrote:

...

There is a bug in RK3399 VOP, when bootloader/kernel only enable VOP Big or VOP Little to display, then VOP IOMMU would failed to reset at the initial time and VOP register couldn't write rightly.

After do the pure reset of VOP module, then things back to right.

Signed-off-by: Yakir Yang ykk@rock-chips.com

drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c index 1c4d5b5..4150323 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c @@ -1292,7 +1292,7 @@ static int vop_initial(struct vop *vop) { const struct vop_data *vop_data = vop->data; const struct vop_reg_data *init_table = vop_data->init_table;

• struct reset_control *ahb_rst;

• struct reset_control *ahb_rst, *axi_rst; int i, ret;

  vop->hclk = devm_clk_get(vop->dev, "hclk_vop");

@@ -1331,6 +1331,19 @@ static int vop_initial(struct vop *vop) }

/*

• * do aclk_reset, reset all vop registers.
  

• */
  

• axi_rst = devm_reset_control_get(vop->dev, "axi");

I don't think you want the managed version here since you only store this in a local variable and hence aren't going to need it afterwards. Just use reset_control_get() and ...

Great, but seems Mark would not accept this fix now :( Maybe I should found the root cause why my bootloader/kernel would broken the VOP.

Thanks, - Yakir

...

• if (IS_ERR(axi_rst)) {

• dev_err(vop->dev, "failed to get axi reset\n");
  

• ret = PTR_ERR(axi_rst);
  

• goto err_disable_aclk;
  

• }
• reset_control_assert(axi_rst);
• usleep_range(10, 20);
• reset_control_deassert(axi_rst);

call reset_control_put() here.

...

• /*
  • do hclk_reset, reset all vop registers.
  */ ahb_rst = devm_reset_control_get(vop->dev, "ahb");

This uses the same pattern, so you might want to consider reworking this as well, though it should be a separate patch.

Thierry