Resetting DISPC when a DISPC output is enabled causes the DSS to go into an inconsistent state. Thus if the bootloader has enabled a display, the hwmod code cannot reset the DISPC module just like that, but the outputs need to be disabled first. Add function dispc_disable_outputs() which disables all active overlay manager and ensure all frame transfers are completed. Modify omap_dss_reset() to call this function and clear DSS_CONTROL, DSS_SDI_CONTROL and DSS_PLL_CONTROL so that DSS is in a clean state when the DSS2 driver starts. This resolves the hang issue(caused by a L3 error during boot) seen on the beagle board C3, which has a factory bootloader that enables display. The issue is resolved with this patch. Acked-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> Tested-by: R, Sricharan <r.sricharan@xxxxxx> Signed-off-by: Archit Taneja <archit@xxxxxx> --- v2: - Added more info in the commit message, fixed some typos. The patch depends on a HWMOD patch series which has been posted by Tomi, it can be tested by applying over the following branch: https://gitorious.org/linux-omap-dss2/linux/commits/master arch/arm/mach-omap2/display.c | 110 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 110 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c index 93db7c1..eab81f4 100644 --- a/arch/arm/mach-omap2/display.c +++ b/arch/arm/mach-omap2/display.c @@ -30,6 +30,30 @@ #include "control.h" +#define DISPC_BASE_OMAP2 0x48050400 +#define DISPC_BASE_OMAP4 0x48041000 + +#define DISPC_REG(base, offset) (base + offset) + +#define DISPC_CONTROL 0x0040 +#define DISPC_CONTROL2 0x0238 +#define DISPC_IRQSTATUS 0x0018 + +#define DSS_SYSCONFIG 0x10 +#define DSS_SYSSTATUS 0x14 +#define DSS_CONTROL 0x40 +#define DSS_SDI_CONTROL 0x44 +#define DSS_PLL_CONTROL 0x48 + +#define LCD_EN_MASK (0x1 << 0) +#define DIGIT_EN_MASK (0x1 << 1) + +#define FRAMEDONE_IRQ_SHIFT 0 +#define EVSYNC_EVEN_IRQ_SHIFT 2 +#define EVSYNC_ODD_IRQ_SHIFT 3 +#define FRAMEDONE2_IRQ_SHIFT 22 +#define FRAMEDONETV_IRQ_SHIFT 24 + static struct platform_device omap_display_device = { .name = "omapdss", .id = -1, @@ -182,6 +206,78 @@ int __init omap_display_init(struct omap_dss_board_info *board_data) return r; } +static void dispc_disable_outputs(void) +{ + u32 val, irq_mask, base; + bool lcd_en, digit_en, lcd2_en = false; + int i, num_mgrs; + + if (cpu_is_omap44xx()) { + base = DISPC_BASE_OMAP4; + num_mgrs = 3; + } else { + base = DISPC_BASE_OMAP2; + num_mgrs = 2; + } + + /* store value of LCDENABLE and DIGITENABLE bits */ + val = omap_readl(DISPC_REG(base, DISPC_CONTROL)); + lcd_en = val & LCD_EN_MASK; + digit_en = val & DIGIT_EN_MASK; + + /* store value of LCDENABLE for LCD2 */ + if (num_mgrs > 2) { + val = omap_readl(DISPC_REG(base, DISPC_CONTROL2)); + lcd2_en = val & LCD_EN_MASK; + } + + /* + * If any manager was enabled, we need to disable it before DSS clocks + * are disabled or DISPC module is reset + */ + if (lcd_en || digit_en || lcd2_en) { + irq_mask = (lcd_en ? 1 : 0) << FRAMEDONE_IRQ_SHIFT; + + if (cpu_is_omap44xx()) + irq_mask |= (digit_en ? 1 : 0) << FRAMEDONETV_IRQ_SHIFT; + else + irq_mask |= (digit_en ? 1 : 0) << EVSYNC_EVEN_IRQ_SHIFT | + (digit_en ? 1 : 0) << EVSYNC_ODD_IRQ_SHIFT; + + irq_mask |= (lcd2_en ? 1 : 0) << FRAMEDONE2_IRQ_SHIFT; + + /* + * clear any previous FRAMEDONE, FRAMEDONETV, EVSYNC_EVEN/ODD + * or FRAMEDONE2 interrupts + */ + omap_writel(irq_mask, DISPC_REG(base, DISPC_IRQSTATUS)); + + /* disable LCD and TV managers */ + val = omap_readl(DISPC_REG(base, DISPC_CONTROL)); + val &= ~(LCD_EN_MASK | DIGIT_EN_MASK); + omap_writel(val, DISPC_REG(base, DISPC_CONTROL)); + + /* disable LCD2 manager */ + if (num_mgrs > 2) { + val = omap_readl(DISPC_REG(base, DISPC_CONTROL2)); + val &= ~LCD_EN_MASK; + omap_writel(val, DISPC_REG(base, DISPC_CONTROL2)); + } + + i = 0; + while ((omap_readl(DISPC_REG(base, DISPC_IRQSTATUS)) & irq_mask) != + irq_mask) { + i++; + if (i > 100) { + printk(KERN_ERR "didn't get FRAMEDONE1/2 or TV" + " interrupt\n"); + break; + } + mdelay(1); + } + } +} + #define MAX_MODULE_SOFTRESET_WAIT 10000 int omap_dss_reset(struct omap_hwmod *oh) { @@ -198,6 +294,20 @@ int omap_dss_reset(struct omap_hwmod *oh) if (oc->_clk) clk_enable(oc->_clk); + dispc_disable_outputs(); + + /* clear SDI registers */ + if (cpu_is_omap3430()) { + omap_hwmod_write(0x0, oh, DSS_SDI_CONTROL); + omap_hwmod_write(0x0, oh, DSS_PLL_CONTROL); + } + + /* + * clear DSS_CONTROL register to switch DSS clock sources to + * PRCM clock, if any + */ + omap_hwmod_write(0x0, oh, DSS_CONTROL); + omap_test_timeout((omap_hwmod_read(oh, oh->class->sysc->syss_offs) & SYSS_RESETDONE_MASK), MAX_MODULE_SOFTRESET_WAIT, c); -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
