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 <tomi.valkeinen@ti.com>
Tested-by: R, Sricharan <r.sricharan@ti.com>
Signed-off-by: Archit Taneja <archit@ti.com>
[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 <paul@pwsan.com>
diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index 941b545..dce9905 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c
@@ -30,6 +30,32 @@
#include <plat/common.h>
#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 @@
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 @@
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);