[U-Boot] [PATCH v3 3/7] usb: host: ehci-generic: add error path and .remove callback

[patrice.chotard at st.com]

From: Patrice Chotard <patrice.chotard at st.com>

use list to save reference to enabled clocks and deasserted resets
in order to respectively disabled and asserted them in case of error
during probe() or during driver removal.

Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
---

v3:	_ keep enabled clocks and deasserted resets reference in list in order to 
	  disable clock or assert resets in error path or in .remove callback
	_ use struct generic_ehci * instead of struct udevice * as parameter for
	  ehci_release_resets() and ehci_release_clocks()

 drivers/usb/host/ehci-generic.c | 162 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 149 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/host/ehci-generic.c b/drivers/usb/host/ehci-generic.c
index 6058e9a..d281218 100644
--- a/drivers/usb/host/ehci-generic.c
+++ b/drivers/usb/host/ehci-generic.c
@@ -11,6 +11,16 @@
 #include <dm.h>
 #include "ehci.h"
 
+struct ehci_clock {
+	struct clk *clk;
+	struct list_head list;
+};
+
+struct ehci_reset {
+	struct reset_ctl *reset;
+	struct list_head list;
+};
+
 /*
  * Even though here we don't explicitly use "struct ehci_ctrl"
  * ehci_register() expects it to be the first thing that resides in
@@ -18,43 +28,169 @@
  */
 struct generic_ehci {
 	struct ehci_ctrl ctrl;
+	struct list_head clks;
+	struct list_head resets;
 };
 
+static int ehci_release_resets(struct generic_ehci *priv)
+{
+	struct ehci_reset *ehci_reset, *tmp;
+	struct reset_ctl *reset;
+	int ret;
+
+	list_for_each_entry_safe(ehci_reset, tmp, &priv->resets, list) {
+		reset = ehci_reset->reset;
+
+		ret = reset_request(reset);
+		if (ret)
+			return ret;
+
+		ret = reset_assert(reset);
+		if (ret)
+			return ret;
+
+		ret = reset_free(reset);
+		if (ret)
+			return ret;
+
+		list_del(&ehci_reset->list);
+	}
+	return 0;
+}
+
+static int ehci_release_clocks(struct generic_ehci *priv)
+{
+	struct ehci_clock *ehci_clock, *tmp;
+	struct clk *clk;
+	int ret;
+
+	list_for_each_entry_safe(ehci_clock, tmp, &priv->clks, list) {
+		clk = ehci_clock->clk;
+
+		clk_request(clk->dev, clk);
+		if (ret)
+			return ret;
+
+		clk_disable(clk);
+
+		ret = clk_free(clk);
+		if (ret)
+			return ret;
+
+		list_del(&ehci_clock->list);
+	}
+	return 0;
+}
+
 static int ehci_usb_probe(struct udevice *dev)
 {
+	struct generic_ehci *priv = dev_get_priv(dev);
 	struct ehci_hccr *hccr;
 	struct ehci_hcor *hcor;
-	int i;
+	int i, ret;
+
+	INIT_LIST_HEAD(&priv->clks);
+	INIT_LIST_HEAD(&priv->resets);
 
 	for (i = 0; ; i++) {
-		struct clk clk;
-		int ret;
+		struct ehci_clock *ehci_clock;
+		struct clk *clk;
 
-		ret = clk_get_by_index(dev, i, &clk);
+		clk = devm_kmalloc(dev, sizeof(*clk), GFP_KERNEL);
+		if (!clk) {
+			error("Can't allocate resource\n");
+			goto clk_err;
+		}
+
+		ret = clk_get_by_index(dev, i, clk);
 		if (ret < 0)
 			break;
-		if (clk_enable(&clk))
+
+		if (clk_enable(clk)) {
 			error("failed to enable clock %d\n", i);
-		clk_free(&clk);
+			clk_free(clk);
+			goto clk_err;
+		}
+		clk_free(clk);
+
+		/*
+		 * add enabled clocks into clks list in order to be disabled
+		 * later on ehci_usb_remove() call or in error path if needed
+		 */
+		ehci_clock = devm_kmalloc(dev, sizeof(*ehci_clock), GFP_KERNEL);
+		if (!ehci_clock) {
+			error("Can't allocate resource\n");
+			goto clk_err;
+		}
+		ehci_clock->clk = clk;
+		list_add(&ehci_clock->list, &priv->clks);
 	}
 
 	for (i = 0; ; i++) {
-		struct reset_ctl reset;
-		int ret;
+		struct ehci_reset *ehci_reset;
+		struct reset_ctl *reset;
+
+		reset = devm_kmalloc(dev, sizeof(*reset), GFP_KERNEL);
+		if (!reset) {
+			error("Can't allocate resource\n");
+			goto clk_err;
+		}
 
-		ret = reset_get_by_index(dev, i, &reset);
+		ret = reset_get_by_index(dev, i, reset);
 		if (ret < 0)
 			break;
-		if (reset_deassert(&reset))
+
+		if (reset_deassert(reset)) {
 			error("failed to deassert reset %d\n", i);
-		reset_free(&reset);
+			reset_free(reset);
+			goto reset_err;
+		}
+		reset_free(reset);
+
+		/*
+		 * add deasserted resets into resets list in order to be
+		 * asserted later on ehci_usb_remove() call or in error
+		 * path if needed
+		 */
+		ehci_reset = devm_kmalloc(dev, sizeof(*ehci_reset), GFP_KERNEL);
+		if (!ehci_reset) {
+			error("Can't allocate resource\n");
+			goto reset_err;
+		}
+		ehci_reset->reset = reset;
+		list_add(&ehci_reset->list, &priv->resets);
 	}
 
 	hccr = map_physmem(dev_get_addr(dev), 0x100, MAP_NOCACHE);
 	hcor = (struct ehci_hcor *)((uintptr_t)hccr +
 				    HC_LENGTH(ehci_readl(&hccr->cr_capbase)));
 
-	return ehci_register(dev, hccr, hcor, NULL, 0, USB_INIT_HOST);
+	ret = ehci_register(dev, hccr, hcor, NULL, 0, USB_INIT_HOST);
+	if (!ret)
+		return ret;
+
+reset_err:
+	ret = ehci_release_resets(priv);
+	if (ret)
+		return ret;
+clk_err:
+	return ehci_release_clocks(priv);
+}
+
+static int ehci_usb_remove(struct udevice *dev)
+{
+	struct generic_ehci *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = ehci_deregister(dev);
+	if (ret)
+		return ret;
+
+	ret = ehci_release_resets(priv);
+	if (ret)
+		return ret;
+
+	return ehci_release_clocks(priv);
 }
 
 static const struct udevice_id ehci_usb_ids[] = {
@@ -67,7 +203,7 @@ U_BOOT_DRIVER(ehci_generic) = {
 	.id	= UCLASS_USB,
 	.of_match = ehci_usb_ids,
 	.probe = ehci_usb_probe,
-	.remove = ehci_deregister,
+	.remove = ehci_usb_remove,
 	.ops	= &ehci_usb_ops,
 	.priv_auto_alloc_size = sizeof(struct generic_ehci),
 	.flags	= DM_FLAG_ALLOC_PRIV_DMA,
-- 
1.9.1