usb_mux: retimer: mux as chained mux and retimer

This makes retimers appear as generic muxes.  By allowing a
chain of muxes they can be stacked up to the new configurations
that zork requires and will continue to work as they did before
on configurations that only have a single mux.

The code used to have two different arrays, 1) muxes and 2)
retimers.  On one of the zork configurations the processor
MUX stopped being the primary mux and the retimer took its
place.  In a different configuration of that same platform
it left the primary and secondary alone but the mux_set
FLIP operation had to be ignored.  Since the same
interfaces needed to be available for both it stopped making
sense to have two different structures and two different
methods of handling them.  This consolodates the two into
one.

The platforms that do not have retimers, this change will
not make any difference. For platforms like zork, it will
remove the retimers and make them chained muxes.  So
testing on trembyle makes sense to verify,

BUG=b:147593660
BRANCH=none
TEST=verify USB still works on trembyle

Change-Id: I286cf1e302f9bd3dd7e81098ec08514a2a009fe3
Signed-off-by: Denis Brockus <dbrockus@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2066794
Commit-Queue: Jett Rink <jettrink@chromium.org>
Reviewed-by: Edward Hill <ecgh@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>

1 files changed, 76 insertions, 121 deletions

diff --git a/include/usb_mux.h b/include/usb_mux.h
index 35350222f0..b606656b61 100644
--- a/include/usb_mux.h
+++ b/include/usb_mux.h
@@ -9,10 +9,15 @@
 #define __CROS_EC_USB_MUX_H
 
 #include "ec_commands.h"
+#include "i2c.h"
 #include "tcpm.h"
 #include "usb_charge.h"
 #include "usb_pd.h"
 
+/* Flags used for usb_mux.flags */
+#define USB_MUX_FLAG_NOT_TCPC BIT(0) /* TCPC/MUX device used only as MUX */
+#define USB_MUX_FLAG_SET_WITHOUT_FLIP BIT(1) /* SET should not flip */
+
 /*
  * USB-C mux state
  *
@@ -21,42 +26,36 @@
  */
 typedef uint8_t mux_state_t;
 
-/*
- * Packing and Unpacking defines used with USB_MUX_FLAG_NOT_TCPC
- * MUX_PORT takes in a USB-C port number and returns the I2C port number
- */
-#define MUX_PORT_AND_ADDR(port, addr) ((port << 8) | (addr & 0xFF))
-#define MUX_PORT(port) (usb_muxes[port].port_addr >> 8)
-#define MUX_ADDR(port) (usb_muxes[port].port_addr & 0xFF)
-
 /* Mux driver function pointers */
+struct usb_mux;
 struct usb_mux_driver {
 	/**
-	 * Initialize USB mux. This is called every time the MUX is access after
-	 * being put in a fully disconnected state (low power mode).
+	 * Initialize USB mux. This is called every time the MUX is
+	 * access after being put in a fully disconnected state (low
+	 * power mode).
 	 *
-	 * @param port usb port of mux (not port_addr)
+	 * @param me usb_mux
 	 * @return EC_SUCCESS on success, non-zero error code on failure.
 	 */
-	int (*init)(int port);
+	int (*init)(const struct usb_mux *me);
 
 	/**
 	 * Set USB mux state.
 	 *
-	 * @param port usb port of mux (not port_addr)
+	 * @param me usb_mux
 	 * @param mux_state State to set mux to.
 	 * @return EC_SUCCESS on success, non-zero error code on failure.
 	 */
-	int (*set)(int port, mux_state_t mux_state);
+	int (*set)(const struct usb_mux *me, mux_state_t mux_state);
 
 	/**
 	 * Get current state of USB mux.
 	 *
-	 * @param port usb port of mux (not port_addr)
+	 * @param me usb_mux
 	 * @param mux_state Gets set to current state of mux.
 	 * @return EC_SUCCESS on success, non-zero error code on failure.
 	 */
-	int (*get)(int port, mux_state_t *mux_state);
+	int (*get)(const struct usb_mux *me, mux_state_t *mux_state);
 
 	/**
 	 * Optional method that is called after the mux fully disconnects.
@@ -65,46 +64,69 @@ struct usb_mux_driver {
 	 * where the TCPC is actively used since the PD state machine
 	 * will put the chip into lower power mode.
 	 *
-	 * @param port usb port of mux (not port_addr)
+	 * @param me usb_mux
 	 * @return EC_SUCCESS on success, non-zero error code on failure.
 	 */
-	int (*enter_low_power_mode)(int port);
+	int (*enter_low_power_mode)(const struct usb_mux *me);
 };
 
-/* Flags used for usb_mux.flags */
-#define USB_MUX_FLAG_NOT_TCPC BIT(0) /* TCPC/MUX device used only as MUX */
-
 /* Describes a USB mux present in the system */
 struct usb_mux {
 	/*
-	 * Used by driver. Muxes that are also the TCPC do not need to specify
-	 * anything for this as they will use the values from tcpc_config_t. If
-	 * this mux is also a TCPC but not used as the TCPC then use the
-	 * MUX_PORT_AND_ADDR to pack the i2c port and i2c address into this
-	 * field and use the USB_MUX_FLAG_NOT_TCPC flag.
+	 * This is index into usb_muxes that points to the start of the
+	 * possible chain of usb_mux entries that this entry is on.
 	 */
-	const int port_addr;
+	int usb_port;
+
+	/*
+	 * I2C port and address. This is optional if your MUX is not
+	 * an I2C interface.  If this is the case, use usb_port to
+	 * index an exernal array to track your connection parameters,
+	 * if they are needed.  One case of this would be a driver
+	 * that will use usb_port as an index into tcpc_config_t to
+	 * gather the necessary information to communicate with the MUX
+	 */
+	uint16_t i2c_port;
+	uint16_t i2c_addr_flags;
 
 	/* Run-time flags with prefix USB_MUX_FLAG_ */
-	const uint32_t flags;
+	uint32_t flags;
 
 	/* Mux driver */
 	const struct usb_mux_driver *driver;
 
+	/* Linked list chain of secondary MUXes. NULL terminated */
+	const struct usb_mux *next_mux;
+
 	/**
 	 * Optional method for tuning for USB mux during mux->driver->init().
 	 *
-	 * @param port usb port of mux (not port_addr)
+	 * @param me usb_mux
 	 * @return EC_SUCCESS on success, non-zero error code on failure.
 	 */
-	int (*board_init)(int port);
+	int (*board_init)(const struct usb_mux *me);
 
 	/*
+	 * USB mux/retimer board specific set mux_state.
+	 *
+	 * @param me usb_mux
+	 * @param mux_state State to set mode to.
+	 * @return EC_SUCCESS on success, non-zero error code on failure.
+	 */
+	int (*board_set)(const struct usb_mux *me, mux_state_t mux_state);
+
+	/*
+	 * TODO: Consider moving this to usb_mux_driver struct
+	 *
 	 * USB Type-C DP alt mode support. Notify Type-C controller
 	 * there is DP dongle hot-plug.
-	 * TODO: Move this function to usb_mux_driver struct.
+	 *
+	 * @param me usb_mux
+	 * @param hpd_lvl Level
+	 * @param hpd_irq IRQ
 	 */
-	void (*hpd_update)(int port, int hpd_lvl, int hpd_irq);
+	void (*hpd_update)(const struct usb_mux *me,
+			   int hpd_lvl, int hpd_irq);
 };
 
 /* Supported USB mux drivers */
@@ -116,114 +138,47 @@ extern const struct usb_mux_driver ps874x_usb_mux_driver;
 extern const struct usb_mux_driver tcpm_usb_mux_driver;
 extern const struct usb_mux_driver virtual_usb_mux_driver;
 
-/* Supported hpd_update functions */
-void virtual_hpd_update(int port, int hpd_lvl, int hpd_irq);
-
 /* USB muxes present in system, ordered by PD port #, defined at board-level */
+#ifdef CONFIG_USB_MUX_RUNTIME_CONFIG
 extern struct usb_mux usb_muxes[];
+#else
+extern const struct usb_mux usb_muxes[];
+#endif
 
-/*
- * Retimer driver function pointers
- *
- * The retimer driver is driven by calls to the MUX API.  These are not
- * called directly anywhere else in the code.
- */
-struct usb_retimer_driver {
-	/**
-	 * Initialize USB retimer. This is called every time the MUX is
-	 * access after being put in a fully disconnected state (low power
-	 * mode).
-	 *
-	 * @param port usb port of redriver (not port_addr)
-	 * @return EC_SUCCESS on success, non-zero error code on failure.
-	 */
-	int (*init)(int port);
-
-	/**
-	 * Put USB retimer in low power mode. This is called when the MUX
-	 * is put into low power mode).
-	 *
-	 * @param port usb port of redriver (not port_addr)
-	 * @return EC_SUCCESS on success, non-zero error code on failure.
-	 */
-	int (*enter_low_power_mode)(int port);
-
-	/**
-	 * Set USB retimer state.
-	 *
-	 * @param port usb port of retimer (not port_addr)
-	 * @param mux_state State to set retimer mode to.
-	 * @return EC_SUCCESS on success, non-zero error code on failure.
-	 */
-	int (*set)(int port, mux_state_t mux_state);
-};
-
-/* Describes a USB retimer present in the system */
-struct usb_retimer {
-	/*
-	 * All of the fields are provided on an as needed basis.
-	 * If your retimer does not use the provided machanism then
-	 * values would not be set (defaulted to 0/NULL).  This
-	 * defaulting includes the driver field, which would indicate
-	 * no retimer driver is to be called.
-	 */
-
-	/* I2C port and slave address */
-	const int i2c_port;
-	uint16_t i2c_addr_flags;
-
-	/* Driver interfaces for this retimer */
-	const struct usb_retimer_driver *driver;
-
-	/*
-	 * USB retimer board specific tune on set mux_state.
-	 *
-	 * @param port usb port of retimer (not port_addr)
-	 * @param mux_state State to set retimer mode to.
-	 * @return EC_SUCCESS on success, non-zero error code on failure.
-	 */
-	int (*tune)(int port, mux_state_t mux_state);
-};
-
-/*
- * USB retimers present in system, ordered by PD port #, defined at
- * board-level
- */
-extern struct usb_retimer usb_retimers[];
+/* Supported hpd_update functions */
+void virtual_hpd_update(const struct usb_mux *me, int hpd_lvl, int hpd_irq);
 
 /*
  * Helper methods that either use tcpc communication or direct i2c
  * communication depending on how the TCPC/MUX device is configured.
  */
 #ifdef CONFIG_USB_PD_TCPM_MUX
-static inline int mux_write(int port, int reg, int val)
+static inline int mux_write(const struct usb_mux *me, int reg, int val)
 {
-	return usb_muxes[port].flags & USB_MUX_FLAG_NOT_TCPC
-		? i2c_write8(MUX_PORT(port), MUX_ADDR(port), reg, val)
-		: tcpc_write(port, reg, val);
+	return me->flags & USB_MUX_FLAG_NOT_TCPC
+		? i2c_write8(me->i2c_port, me->i2c_addr_flags, reg, val)
+		: tcpc_write(me->usb_port, reg, val);
 }
 
-static inline int mux_read(int port, int reg, int *val)
+static inline int mux_read(const struct usb_mux *me, int reg, int *val)
 {
-	return usb_muxes[port].flags & USB_MUX_FLAG_NOT_TCPC
-		? i2c_read8(MUX_PORT(port), MUX_ADDR(port), reg, val)
-		: tcpc_read(port, reg, val);
+	return me->flags & USB_MUX_FLAG_NOT_TCPC
+		? i2c_read8(me->i2c_port, me->i2c_addr_flags, reg, val)
+		: tcpc_read(me->usb_port, reg, val);
 }
 
-static inline int mux_write16(int port, int reg, int val)
+static inline int mux_write16(const struct usb_mux *me, int reg, int val)
 {
-	return usb_muxes[port].flags & USB_MUX_FLAG_NOT_TCPC
-		? i2c_write16(MUX_PORT(port), MUX_ADDR(port),
-			      reg, val)
-		: tcpc_write16(port, reg, val);
+	return me->flags & USB_MUX_FLAG_NOT_TCPC
+		? i2c_write16(me->i2c_port, me->i2c_addr_flags, reg, val)
+		: tcpc_write16(me->usb_port, reg, val);
 }
 
-static inline int mux_read16(int port, int reg, int *val)
+static inline int mux_read16(const struct usb_mux *me, int reg, int *val)
 {
-	return usb_muxes[port].flags & USB_MUX_FLAG_NOT_TCPC
-		? i2c_read16(MUX_PORT(port), MUX_ADDR(port),
-			     reg, val)
-		: tcpc_read16(port, reg, val);
+	return me->flags & USB_MUX_FLAG_NOT_TCPC
+		? i2c_read16(me->i2c_port, me->i2c_addr_flags, reg, val)
+		: tcpc_read16(me->usb_port, reg, val);
 }
 #endif /* CONFIG_USB_PD_TCPM_MUX */