From b923d40dd4211c4ef7d4efa2bd81b7ca1d8744c1 Mon Sep 17 00:00:00 2001 From: Archit Taneja Date: Thu, 6 Oct 2011 18:04:08 -0600 Subject: ARM: OMAP2PLUS: DSS: Ensure DSS works correctly if display is enabled in bootloader 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. Thanks to Tomi and Sricharan for some additional testing. Acked-by: Tomi Valkeinen Tested-by: R, Sricharan Signed-off-by: Archit Taneja [paul@pwsan.com: restructured code, removed omap_{read,write}l(), removed cpu_is_omap*() calls and converted to dev_attr] Signed-off-by: Paul Walmsley --- arch/arm/mach-omap2/display.c | 124 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 124 insertions(+) (limited to 'arch/arm/mach-omap2/display.c') diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c index 941b5459707f..dce9905d64bb 100644 --- a/arch/arm/mach-omap2/display.c +++ b/arch/arm/mach-omap2/display.c @@ -30,6 +30,32 @@ #include #include "control.h" +#include "display.h" + +#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 + +/* + * FRAMEDONE_IRQ_TIMEOUT: how long (in milliseconds) to wait during DISPC + * reset before deciding that something has gone wrong + */ +#define FRAMEDONE_IRQ_TIMEOUT 100 static struct platform_device omap_display_device = { .name = "omapdss", @@ -174,6 +200,90 @@ int __init omap_display_init(struct omap_dss_board_info *board_data) return r; } +static void dispc_disable_outputs(void) +{ + u32 v, irq_mask = 0; + bool lcd_en, digit_en, lcd2_en = false; + int i; + struct omap_dss_dispc_dev_attr *da; + struct omap_hwmod *oh; + + oh = omap_hwmod_lookup("dss_dispc"); + if (!oh) { + WARN(1, "display: could not disable outputs during reset - could not find dss_dispc hwmod\n"); + return; + } + + if (!oh->dev_attr) { + pr_err("display: could not disable outputs during reset due to missing dev_attr\n"); + return; + } + + da = (struct omap_dss_dispc_dev_attr *)oh->dev_attr; + + /* store value of LCDENABLE and DIGITENABLE bits */ + v = omap_hwmod_read(oh, DISPC_CONTROL); + lcd_en = v & LCD_EN_MASK; + digit_en = v & DIGIT_EN_MASK; + + /* store value of LCDENABLE for LCD2 */ + if (da->manager_count > 2) { + v = omap_hwmod_read(oh, DISPC_CONTROL2); + lcd2_en = v & LCD_EN_MASK; + } + + if (!(lcd_en | digit_en | lcd2_en)) + return; /* no managers currently enabled */ + + /* + * If any manager was enabled, we need to disable it before + * DSS clocks are disabled or DISPC module is reset + */ + if (lcd_en) + irq_mask |= 1 << FRAMEDONE_IRQ_SHIFT; + + if (digit_en) { + if (da->has_framedonetv_irq) { + irq_mask |= 1 << FRAMEDONETV_IRQ_SHIFT; + } else { + irq_mask |= 1 << EVSYNC_EVEN_IRQ_SHIFT | + 1 << EVSYNC_ODD_IRQ_SHIFT; + } + } + + if (lcd2_en) + irq_mask |= 1 << FRAMEDONE2_IRQ_SHIFT; + + /* + * clear any previous FRAMEDONE, FRAMEDONETV, + * EVSYNC_EVEN/ODD or FRAMEDONE2 interrupts + */ + omap_hwmod_write(irq_mask, oh, DISPC_IRQSTATUS); + + /* disable LCD and TV managers */ + v = omap_hwmod_read(oh, DISPC_CONTROL); + v &= ~(LCD_EN_MASK | DIGIT_EN_MASK); + omap_hwmod_write(v, oh, DISPC_CONTROL); + + /* disable LCD2 manager */ + if (da->manager_count > 2) { + v = omap_hwmod_read(oh, DISPC_CONTROL2); + v &= ~LCD_EN_MASK; + omap_hwmod_write(v, oh, DISPC_CONTROL2); + } + + i = 0; + while ((omap_hwmod_read(oh, DISPC_IRQSTATUS) & irq_mask) != + irq_mask) { + i++; + if (i > FRAMEDONE_IRQ_TIMEOUT) { + pr_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) { @@ -190,6 +300,20 @@ 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); -- cgit v1.2.2