[U-Boot] [PATCH V2] usb: ehci-mx6: Fix bus enumeration for DM case

[Marek Vasut]

The EHCI iMX6 driver is only partly converted to DT probing and
still uses a tremendous amount of hard-coded addresses. Worse,
the driver uses hard-coded SoC-model-specific base addresses, which
are derived from values protected by SoC-specific macros, hence the
driver is also compiled for a specific SoC model. Even worse, the
driver depends on specific sequential indexing of the controllers,
from which it derives offsets in the PHY and ANATOP register sets.

However, when the driver is probed from DT, the indexing is not
correct. In fact, each controller has index 0. This patch derives
the index for DT probing case from the controller base addresses,
which is not the way this should be done, however it is the least
intrusive approach, favorable this close to release.

The necessary steps to convert this driver fully to DT probing are
described inside the patch, however this should be done in the next
release and depends on iMX clock driver patches.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Abel Vesa <abel.vesa at nxp.com>
Cc: Adam Ford <aford173 at gmail.com>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Ludwig Zenz <lzenz at dh-electronics.com>
Cc: Lukasz Majewski <lukma at denx.de>
Cc: Peng Fan <peng.fan at nxp.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: Vagrant Cascadian <vagrant at debian.org>
---
V2: Derive the controller index from it's base address
---
 drivers/usb/host/ehci-mx6.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/drivers/usb/host/ehci-mx6.c b/drivers/usb/host/ehci-mx6.c
index 33abfeada0..e9e6ed596d 100644
--- a/drivers/usb/host/ehci-mx6.c
+++ b/drivers/usb/host/ehci-mx6.c
@@ -503,6 +503,42 @@ static int ehci_usb_ofdata_to_platdata(struct udevice *dev)
 	return 0;
 }
 
+static int ehci_usb_bind(struct udevice *dev)
+{
+	/*
+	 * TODO:
+	 * This driver is only partly converted to DT probing and still uses
+	 * a tremendous amount of hard-coded addresses. To make things worse,
+	 * the driver depends on specific sequential indexing of controllers,
+	 * from which it derives offsets in the PHY and ANATOP register sets.
+	 *
+	 * Here we attempt to calculate these indexes from DT information as
+	 * well as we can. The USB controllers on all existing iMX6/iMX7 SoCs
+	 * are placed next to each other, at addresses incremented by 0x200.
+	 * Thus, the index is derived from the multiple of 0x200 offset from
+	 * the first controller address.
+	 *
+	 * However, to complete conversion of this driver to DT probing, the
+	 * following has to be done:
+	 * - DM clock framework support for iMX must be implemented
+	 * - usb_power_config() has to be converted to clock framework
+	 *   -> Thus, the ad-hoc "index" variable goes away.
+	 * - USB PHY handling has to be factored out into separate driver
+	 *   -> Thus, the ad-hoc "index" variable goes away from the PHY
+	 *      code, the PHY driver must parse it's address from DT. This
+	 *      USB driver must find the PHY driver via DT phandle.
+	 *   -> usb_power_config() shall be moved to PHY driver
+	 * With these changes in place, the ad-hoc indexing goes away and
+	 * the driver is fully converted to DT probing.
+	 */
+	fdt_size_t size;
+	fdt_addr_t addr = devfdt_get_addr_size_index(dev, 0, &size);
+
+	dev->req_seq = (addr - USB_BASE_ADDR) / size;
+
+	return 0;
+}
+
 static int ehci_usb_probe(struct udevice *dev)
 {
 	struct usb_platdata *plat = dev_get_platdata(dev);
@@ -564,6 +600,7 @@ U_BOOT_DRIVER(usb_mx6) = {
 	.id	= UCLASS_USB,
 	.of_match = mx6_usb_ids,
 	.ofdata_to_platdata = ehci_usb_ofdata_to_platdata,
+	.bind	= ehci_usb_bind,
 	.probe	= ehci_usb_probe,
 	.remove = ehci_deregister,
 	.ops	= &ehci_usb_ops,
-- 
2.20.1