On Wed, Mar 04, 2015 at 01:58:55PM +0800, Liu Ying wrote: > The LCDIF engines embedded in i.MX6sl and i.MX6sx SoCs need the axi clock > as the engine's system clock. The clock should be enabled when accessing > LCDIF registers, otherwise the kernel would hang up. We should also keep > the clock being enabled when the engine is being active to scan out frames > from memory. This patch makes sure the axi clock is enabled when accessing > registers so that the kernel hang up issue can be fixed. > > Reported-by: Peter Chen <[email protected]> > Signed-off-by: Liu Ying <[email protected]> > --- > drivers/video/fbdev/mxsfb.c | 70 > ++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 56 insertions(+), 14 deletions(-) > > diff --git a/drivers/video/fbdev/mxsfb.c b/drivers/video/fbdev/mxsfb.c > index f8ac4a4..a8cf3b2 100644 > --- a/drivers/video/fbdev/mxsfb.c > +++ b/drivers/video/fbdev/mxsfb.c > @@ -316,6 +316,18 @@ static int mxsfb_check_var(struct fb_var_screeninfo *var, > return 0; > } > > +static inline void mxsfb_enable_axi_clk(struct mxsfb_info *host) > +{ > + if (host->clk_axi) > + clk_prepare_enable(host->clk_axi); > +} > + > +static inline void mxsfb_disable_axi_clk(struct mxsfb_info *host) > +{ > + if (host->clk_axi) > + clk_disable_unprepare(host->clk_axi); > +} > + > static void mxsfb_enable_controller(struct fb_info *fb_info) > { > struct mxsfb_info *host = to_imxfb_host(fb_info); > @@ -333,14 +345,13 @@ static void mxsfb_enable_controller(struct fb_info > *fb_info) > } > } > > - if (host->clk_axi) > - clk_prepare_enable(host->clk_axi); > - > if (host->clk_disp_axi) > clk_prepare_enable(host->clk_disp_axi); > clk_prepare_enable(host->clk); > clk_set_rate(host->clk, PICOS2KHZ(fb_info->var.pixclock) * 1000U); > > + mxsfb_enable_axi_clk(host); > + > /* if it was disabled, re-enable the mode again */ > writel(CTRL_DOTCLK_MODE, host->base + LCDC_CTRL + REG_SET); > > @@ -380,11 +391,11 @@ static void mxsfb_disable_controller(struct fb_info > *fb_info) > reg = readl(host->base + LCDC_VDCTRL4); > writel(reg & ~VDCTRL4_SYNC_SIGNALS_ON, host->base + LCDC_VDCTRL4); > > + mxsfb_disable_axi_clk(host); > + > clk_disable_unprepare(host->clk); > if (host->clk_disp_axi) > clk_disable_unprepare(host->clk_disp_axi); > - if (host->clk_axi) > - clk_disable_unprepare(host->clk_axi); > > host->enabled = 0; > > @@ -421,6 +432,8 @@ static int mxsfb_set_par(struct fb_info *fb_info) > mxsfb_disable_controller(fb_info); > } > > + mxsfb_enable_axi_clk(host); > + > /* clear the FIFOs */ > writel(CTRL1_FIFO_CLEAR, host->base + LCDC_CTRL1 + REG_SET); > > @@ -438,6 +451,7 @@ static int mxsfb_set_par(struct fb_info *fb_info) > ctrl |= CTRL_SET_WORD_LENGTH(3); > switch (host->ld_intf_width) { > case STMLCDIF_8BIT: > + mxsfb_disable_axi_clk(host); > dev_err(&host->pdev->dev, > "Unsupported LCD bus width mapping\n"); > return -EINVAL; > @@ -451,6 +465,7 @@ static int mxsfb_set_par(struct fb_info *fb_info) > writel(CTRL1_SET_BYTE_PACKAGING(0x7), host->base + LCDC_CTRL1); > break; > default: > + mxsfb_disable_axi_clk(host); > dev_err(&host->pdev->dev, "Unhandled color depth of %u\n", > fb_info->var.bits_per_pixel); > return -EINVAL; > @@ -504,6 +519,8 @@ static int mxsfb_set_par(struct fb_info *fb_info) > fb_info->fix.line_length * fb_info->var.yoffset, > host->base + host->devdata->next_buf); > > + mxsfb_disable_axi_clk(host); > + > if (reenable) > mxsfb_enable_controller(fb_info); > > @@ -582,10 +599,16 @@ static int mxsfb_pan_display(struct fb_var_screeninfo > *var, > > offset = fb_info->fix.line_length * var->yoffset; > > + if (!host->enabled) > + mxsfb_enable_axi_clk(host); > + > /* update on next VSYNC */ > writel(fb_info->fix.smem_start + offset, > host->base + host->devdata->next_buf); > > + if (!host->enabled) > + mxsfb_disable_axi_clk(host); > + > return 0; > } > > @@ -608,13 +631,17 @@ static int mxsfb_restore_mode(struct mxsfb_info *host, > unsigned line_count; > unsigned period; > unsigned long pa, fbsize; > - int bits_per_pixel, ofs; > + int bits_per_pixel, ofs, ret = 0; > u32 transfer_count, vdctrl0, vdctrl2, vdctrl3, vdctrl4, ctrl; > > + mxsfb_enable_axi_clk(host); > + > /* Only restore the mode when the controller is running */ > ctrl = readl(host->base + LCDC_CTRL); > - if (!(ctrl & CTRL_RUN)) > - return -EINVAL; > + if (!(ctrl & CTRL_RUN)) { > + ret = -EINVAL; > + goto err; > + } > > vdctrl0 = readl(host->base + LCDC_VDCTRL0); > vdctrl2 = readl(host->base + LCDC_VDCTRL2); > @@ -635,7 +662,8 @@ static int mxsfb_restore_mode(struct mxsfb_info *host, > break; > case 1: > default: > - return -EINVAL; > + ret = -EINVAL; > + goto err; > } > > fb_info->var.bits_per_pixel = bits_per_pixel; > @@ -673,10 +701,14 @@ static int mxsfb_restore_mode(struct mxsfb_info *host, > > pa = readl(host->base + host->devdata->cur_buf); > fbsize = fb_info->fix.line_length * vmode->yres; > - if (pa < fb_info->fix.smem_start) > - return -EINVAL; > - if (pa + fbsize > fb_info->fix.smem_start + fb_info->fix.smem_len) > - return -EINVAL; > + if (pa < fb_info->fix.smem_start) { > + ret = -EINVAL; > + goto err; > + } > + if (pa + fbsize > fb_info->fix.smem_start + fb_info->fix.smem_len) { > + ret = -EINVAL; > + goto err; > + } > ofs = pa - fb_info->fix.smem_start; > if (ofs) { > memmove(fb_info->screen_base, fb_info->screen_base + ofs, > fbsize); > @@ -689,7 +721,11 @@ static int mxsfb_restore_mode(struct mxsfb_info *host, > clk_prepare_enable(host->clk); > host->enabled = 1; > > - return 0; > +err: > + if (ret) > + mxsfb_disable_axi_clk(host); > + > + return ret; > } > > static int mxsfb_init_fbinfo_dt(struct mxsfb_info *host, > @@ -915,7 +951,9 @@ static int mxsfb_probe(struct platform_device *pdev) > } > > if (!host->enabled) { > + mxsfb_enable_axi_clk(host); > writel(0, host->base + LCDC_CTRL); > + mxsfb_disable_axi_clk(host); > mxsfb_set_par(fb_info); > mxsfb_enable_controller(fb_info); > } > @@ -954,11 +992,15 @@ static void mxsfb_shutdown(struct platform_device *pdev) > struct fb_info *fb_info = platform_get_drvdata(pdev); > struct mxsfb_info *host = to_imxfb_host(fb_info); > > + mxsfb_enable_axi_clk(host); > + > /* > * Force stop the LCD controller as keeping it running during reboot > * might interfere with the BootROM's boot mode pads sampling. > */ > writel(CTRL_RUN, host->base + LCDC_CTRL + REG_CLR); > + > + mxsfb_disable_axi_clk(host); > } > > static struct platform_driver mxsfb_driver = { > -- > 2.1.0 >
It fixed the system hang issue at yocto rootfs at imx6sx sdb and imx6sl sdb boards. Tested-by: Peter Chen <[email protected]> -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
