On Wed, Jul 17, 2019 at 07:06:02PM +0200, Ahmad Fatoum wrote: > From: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > Due to incorrect placement of the clock gate cell in the ldb_di[x]_clk > tree, the glitchy parent mux of ldb_di[x]_clk can cause a glitch to > enter the ldb_di_ipu_div divider. If the divider gets locked up, no > ldb_di[x]_clk is generated, and the LVDS display will hang when the > ipu_di_clk is sourced from ldb_di_clk. > > To fix the problem, both the new and current parent of the ldb_di_clk > should be disabled before the switch. As this can not be guaranteed by > the clock framework during runtime, make the ldb_di[x]_sel muxes read-only. > A workaround to set the muxes once during boot could be added to the > kernel or bootloader. > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > Signed-off-by: Fabio Estevam <fabio.estevam@xxxxxxx> > Signed-off-by: Shawn Guo <shawnguo@xxxxxxxxxx> > [afa: reviewed for barebox] > Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > Tested-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx> > [afa: ported from Linux kernel commit 03d576f202] Should this line be further above, or were the lines above all part of the Linux commit? - Roland > [afa: added exception for i.MX6QP, see kernel commit f4a0a6c309] > [afa: added cpu_has_err009219 helper function] > Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx> > --- > drivers/clk/imx/clk-imx6.c | 17 +++++++++++++++-- > drivers/clk/imx/clk.h | 8 ++++++++ > 2 files changed, 23 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/imx/clk-imx6.c b/drivers/clk/imx/clk-imx6.c > index 6f19535be7ba..61819ff9744d 100644 > --- a/drivers/clk/imx/clk-imx6.c > +++ b/drivers/clk/imx/clk-imx6.c > @@ -64,6 +64,13 @@ static inline int cpu_mx6_is_plus(void) > return cpu_mx6_is_mx6qp() || cpu_mx6_is_mx6dp(); > } > > +/* i.MX6 Quad/Dual/DualLite/Solo are all affected */ > +static inline int cpu_mx6_has_err009219(void) > +{ > + return cpu_mx6_is_mx6d() || cpu_mx6_is_mx6q() || > + cpu_mx6_is_mx6dl() || cpu_mx6_is_mx6s(); > +} > + > static const char *step_sels[] = { > "osc", > "pll2_pfd2_396m", > @@ -316,8 +323,14 @@ static void imx6_add_video_clks(void __iomem *anab, void __iomem *cb) > > imx6q_mmdc_ch1_mask_handshake(cb); > > - clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_p("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > - clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_p("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > + if (cpu_mx6_has_err009219()) { > + clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_ldb("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > + clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_ldb("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > + } else { > + clks[IMX6QDL_CLK_LDB_DI0_SEL] = imx_clk_mux_p("ldb_di0_sel", cb + 0x2c, 9, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > + clks[IMX6QDL_CLK_LDB_DI1_SEL] = imx_clk_mux_p("ldb_di1_sel", cb + 0x2c, 12, 3, ldb_di_sels, ARRAY_SIZE(ldb_di_sels)); > + } > + > clks[IMX6QDL_CLK_IPU1_DI0_PRE_SEL] = imx_clk_mux_p("ipu1_di0_pre_sel", cb + 0x34, 6, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels)); > clks[IMX6QDL_CLK_IPU1_DI1_PRE_SEL] = imx_clk_mux_p("ipu1_di1_pre_sel", cb + 0x34, 15, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels)); > clks[IMX6QDL_CLK_IPU2_DI0_PRE_SEL] = imx_clk_mux_p("ipu2_di0_pre_sel", cb + 0x38, 6, 3, ipu_di_pre_sels, ARRAY_SIZE(ipu_di_pre_sels)); > diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h > index 875c76a8b3e4..04286f03f727 100644 > --- a/drivers/clk/imx/clk.h > +++ b/drivers/clk/imx/clk.h > @@ -39,6 +39,14 @@ static inline struct clk *imx_clk_divider_table(const char *name, > width, table, 0); > } > > +static inline struct clk *imx_clk_mux_ldb(const char *name, void __iomem *reg, > + u8 shift, u8 width, const char **parents, int num_parents) > +{ > + return clk_mux(name, CLK_SET_RATE_NO_REPARENT | CLK_SET_RATE_PARENT, reg, > + shift, width, parents, num_parents, CLK_MUX_READ_ONLY); > +} > + > + > static inline struct clk *imx_clk_fixed_factor(const char *name, > const char *parent, unsigned int mult, unsigned int div) > { > -- > 2.20.1 > > > _______________________________________________ > barebox mailing list > barebox@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/barebox > -- Roland Hieber | r.hieber@xxxxxxxxxxxxxx | Pengutronix e.K. | https://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim | Phone: +49-5121-206917-5086 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox