drivers/intel/mipi_camera: Add reference counting for shared resources

This change updates the mipi_camera driver to handle shared power
resource between multiple cameras. This is achieved by adding a guard
variable and methods to manipulate the guard variable before calling
the actual platform method which enables or disables the resource.
PowerResource will call these guarded methods to enable or disable the
resource. This protects the shared resource from being enabled or
disabled multiple times while the other camera is using the resource.

Example:
Consider a platform where two cameras are sharing a GPIO resource 0xXX
and both the cameras calls enable and disable guarded methods for this
GPIO. Actual platform disable method for the GPIO is called only after
the last camera using the GPIO calls DSBx method and RESx becomes 0.

Scope (\_SB.PCI0)
{
	Name (RESx, Zero)
	Method (ENBx, 0, Serialized)
	{
		If ((RESx == Zero))
		{
			\_SB.PCI0.STXS (0xXX)
		}

		RESx++
	}

	Method (DSBx, 0, Serialized)
	{
		If ((RESx > Zero))
		{
			RESx--
		}

		If ((RESx == Zero))
		{
			\_SB.PCI0.CTXS (0xXX)
		}
	}
}

Change-Id: I1468459d5bbb2fb07bef4e0590c96dd4dbab0d9c
Signed-off-by: Sugnan Prabhu S <sugnan.prabhu.s@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43003
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 24 insertions, 2 deletions

diff --git a/src/drivers/intel/mipi_camera/chip.h b/src/drivers/intel/mipi_camera/chip.h
index d133f7df86..d91e1e749d 100644
--- a/src/drivers/intel/mipi_camera/chip.h
+++ b/src/drivers/intel/mipi_camera/chip.h
@@ -13,6 +13,7 @@
 #define MAX_CLK_CONFIGS		2
 #define MAX_GPIO_CONFIGS	4
 #define MAX_PWR_OPS		5
+#define MAX_GUARDED_RESOURCES	10
 
 #define SEQ_OPS_CLK_ENABLE(ind, delay) \
 	{ .type = IMGCLK, .index = (ind), .action = ENABLE, .delay_ms = (delay) }
@@ -70,15 +71,36 @@ enum intel_power_action_type {
 };
 
 enum ctrl_type {
-	IMGCLK = 1,
+	UNKNOWN_CTRL,
+	IMGCLK,
 	GPIO
 };
 
 enum action_type {
-	ENABLE = 1,
+	UNKNOWN_ACTION,
+	ENABLE,
 	DISABLE
 };
 
+struct camera_resource {
+	uint8_t type;
+	uint8_t id;
+};
+
+struct camera_resource_manager {
+	uint8_t cnt;
+	struct camera_resource resource[MAX_GUARDED_RESOURCES];
+};
+
+struct resource_config {
+	enum action_type action;
+	enum ctrl_type type;
+	union {
+		const struct clk_config *clk_conf;
+		const struct gpio_config *gpio_conf;
+	};
+};
+
 struct clk_config {
 	/* IMGCLKOUT_x being used for a port */
 	uint8_t clknum;