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Commit 49ea86f3 authored by Tomi Valkeinen's avatar Tomi Valkeinen
Browse files

OMAP: DSS2: DISPC: Fix context save/restore 



The current method of saving and restoring the context could cause a
restore before saving, effectively "restoring" zero values to registers.

Add ctx_valid field to indicate if the saved context is valid and can be
restored.

Also restructure the code to save the ctx_loss_count in save_context(),
which makes more sense than the previous method of storing new
ctx_loss_count in dispc_need_ctx_restore.

Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
parent 39020710

drivers/video/omap2/dss/dispc.c

+38 −59
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ static struct { 
	u32 error_irqs;

	struct work_struct error_work;



	bool		ctx_valid;

	u32		ctx[DISPC_SZ_REGS / sizeof(u32)];



#ifdef CONFIG_OMAP2_DSS_COLLECT_IRQ_STATS
@@ -146,6 +147,23 @@ static inline u32 dispc_read_reg(const u16 idx) 
	return __raw_readl(dispc.base + idx);

}



static int dispc_get_ctx_loss_count(void)

{

	struct device *dev = &dispc.pdev->dev;

	struct omap_display_platform_data *pdata = dev->platform_data;

	struct omap_dss_board_info *board_data = pdata->board_data;

	int cnt;



	if (!board_data->get_context_loss_count)

		return -ENOENT;



	cnt = board_data->get_context_loss_count(dev);



	WARN_ONCE(cnt < 0, "get_context_loss_count failed: %d\n", cnt);



	return cnt;

}



#define SR(reg) \

	dispc.ctx[DISPC_##reg / sizeof(u32)] = dispc_read_reg(DISPC_##reg)

#define RR(reg) \
@@ -322,14 +340,30 @@ static void dispc_save_context(void) 


	if (dss_has_feature(FEAT_CORE_CLK_DIV))

		SR(DIVISOR);



	dispc.ctx_loss_cnt = dispc_get_ctx_loss_count();

	dispc.ctx_valid = true;



	DSSDBG("context saved, ctx_loss_count %d\n", dispc.ctx_loss_cnt);

}



static void dispc_restore_context(void)

{

	int i;

	int i, ctx;



	DSSDBG("dispc_restore_context\n");



	if (!dispc.ctx_valid)

		return;



	ctx = dispc_get_ctx_loss_count();



	if (ctx >= 0 && ctx == dispc.ctx_loss_cnt)

		return;



	DSSDBG("ctx_loss_count: saved %d, current %d\n",

			dispc.ctx_loss_cnt, ctx);



	/*RR(IRQENABLE);*/

	/*RR(CONTROL);*/

	RR(CONFIG);
@@ -508,65 +542,13 @@ static void dispc_restore_context(void) 
	 * the context is fully restored

	 */

	RR(IRQENABLE);



	DSSDBG("context restored\n");

}



#undef SR

#undef RR



static void dispc_init_ctx_loss_count(void)

{

	struct device *dev = &dispc.pdev->dev;

	struct omap_display_platform_data *pdata = dev->platform_data;

	struct omap_dss_board_info *board_data = pdata->board_data;

	int cnt = 0;



	/*

	 * get_context_loss_count returns negative on error. We'll ignore the

	 * error and store the error to ctx_loss_cnt, which will cause

	 * dispc_need_ctx_restore() call to return true.

	 */



	if (board_data->get_context_loss_count)

		cnt = board_data->get_context_loss_count(dev);



	WARN_ON(cnt < 0);



	dispc.ctx_loss_cnt = cnt;



	DSSDBG("initial ctx_loss_cnt %u\n", cnt);

}



static bool dispc_need_ctx_restore(void)

{

	struct device *dev = &dispc.pdev->dev;

	struct omap_display_platform_data *pdata = dev->platform_data;

	struct omap_dss_board_info *board_data = pdata->board_data;

	int cnt;



	/*

	 * If get_context_loss_count is not available, assume that we need

	 * context restore always.

	 */

	if (!board_data->get_context_loss_count)

		return true;



	cnt = board_data->get_context_loss_count(dev);

	if (cnt < 0) {

		dev_err(dev, "getting context loss count failed, will force "

				"context restore\n");

		dispc.ctx_loss_cnt = cnt;

		return true;

	}



	if (cnt == dispc.ctx_loss_cnt)

		return false;



	DSSDBG("ctx_loss_cnt %d -> %d\n", dispc.ctx_loss_cnt, cnt);

	dispc.ctx_loss_cnt = cnt;



	return true;

}



int dispc_runtime_get(void)

{

	int r;
@@ -3709,8 +3691,6 @@ static int omap_dispchw_probe(struct platform_device *pdev) 
		goto err_irq;

	}



	dispc_init_ctx_loss_count();



	pm_runtime_enable(&pdev->dev);



	r = dispc_runtime_get();
@@ -3769,7 +3749,6 @@ static int dispc_runtime_resume(struct device *dev) 
		return r;



	clk_enable(dispc.dss_clk);

	if (dispc_need_ctx_restore())

	dispc_restore_context();



	return 0;