[RFC PATCH 2/2] usb: chipidea: use the generic ehci_writel override for i.MX28

[Daniel Palmer <daniel@thingy.jp>]

From: Daniel Palmer <daniel@0x0f.com>

The EHCI core carries an imx28_write_fix flag baked into ehci_writel()
that special-cases the i.MX28's need for a swp instruction when writing
the EHCI registers.

Now that the EHCI core provides a generic ehci_writel override hook,
convert the chipidea host glue to install its own writel via that hook
and drop the i.MX28 special case from the core, keeping ehci_writel()
free of SoC-specific knowledge.

Signed-off-by: Daniel Palmer <daniel@0x0f.com>
---
 drivers/usb/chipidea/Kconfig |  1 +
 drivers/usb/chipidea/host.c  | 17 ++++++++++++++++-
 drivers/usb/host/ehci.h      | 19 ++-----------------
 3 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/drivers/usb/chipidea/Kconfig b/drivers/usb/chipidea/Kconfig
index bab45bc62361..5bada84943e2 100644
--- a/drivers/usb/chipidea/Kconfig
+++ b/drivers/usb/chipidea/Kconfig
@@ -29,6 +29,7 @@ config USB_CHIPIDEA_HOST
 	bool "ChipIdea host controller"
 	depends on USB_EHCI_HCD
 	select USB_EHCI_ROOT_HUB_TT
+	select HAVE_BROKEN_EHCI_HCD if SOC_IMX28
 	help
 	  Say Y here to enable host controller functionality of the
 	  ChipIdea driver.
diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
index ced6076a8248..820bdea5da12 100644
--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -117,6 +117,18 @@ static irqreturn_t host_irq(struct ci_hdrc *ci)
 	return usb_hcd_irq(ci->irq, ci->hcd);
 }
 
+#ifdef CONFIG_SOC_IMX28
+/*
+ * The i.MX28 needs a swp instruction rather than a normal write to the
+ * EHCI registers; provide it through the generic ehci_writel override.
+ */
+static void ci_hdrc_ehci_writel(const struct ehci_hcd *ehci,
+				const unsigned int val, __u32 __iomem *regs)
+{
+	asm("swp %0, %0, [%1]" : : "r"(val), "r"(regs));
+}
+#endif
+
 static int host_start(struct ci_hdrc *ci)
 {
 	struct usb_hcd *hcd;
@@ -150,7 +162,10 @@ static int host_start(struct ci_hdrc *ci)
 	ehci->caps = ci->hw_bank.cap;
 	ehci->has_hostpc = ci->hw_bank.lpm;
 	ehci->has_tdi_phy_lpm = ci->hw_bank.lpm;
-	ehci->imx28_write_fix = ci->imx28_write_fix;
+#ifdef CONFIG_SOC_IMX28
+	if (ci->imx28_write_fix)
+		ehci->ehci_writel = ci_hdrc_ehci_writel;
+#endif
 	ehci->has_ci_pec_bug = ci->has_portsc_pec_bug;
 
 	priv = (struct ehci_ci_priv *)ehci->priv;
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index f592cc26e494..616b01314bfe 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -218,7 +218,6 @@ struct ehci_hcd {			/* one per controller */
 	unsigned		has_synopsys_hc_bug:1; /* Synopsys HC */
 	unsigned		frame_index_bug:1; /* MosChip (AKA NetMos) */
 	unsigned		need_oc_pp_cycle:1; /* MPC834X port power */
-	unsigned		imx28_write_fix:1; /* For Freescale i.MX28 */
 	unsigned		spurious_oc:1;
 	unsigned		is_aspeed:1;
 	unsigned		zx_wakeup_clear_needed:1;
@@ -778,18 +777,6 @@ static inline unsigned int ehci_readl(const struct ehci_hcd *ehci,
 #endif
 }
 
-#ifdef CONFIG_SOC_IMX28
-static inline void imx28_ehci_writel(const unsigned int val,
-		volatile __u32 __iomem *addr)
-{
-	__asm__ ("swp %0, %0, [%1]" : : "r"(val), "r"(addr));
-}
-#else
-static inline void imx28_ehci_writel(const unsigned int val,
-		volatile __u32 __iomem *addr)
-{
-}
-#endif
 static inline void ehci_writel(const struct ehci_hcd *ehci,
 		const unsigned int val, __u32 __iomem *regs)
 {
@@ -798,13 +785,11 @@ static inline void ehci_writel(const struct ehci_hcd *ehci,
 		writel_be(val, regs) :
 		writel(val, regs);
 #else
-	if (ehci->imx28_write_fix)
-		imx28_ehci_writel(val, regs);
 #ifdef CONFIG_HAVE_BROKEN_EHCI_HCD
-	else if (ehci->ehci_writel)
+	if (ehci->ehci_writel)
 		ehci->ehci_writel(ehci, val, regs);
-#endif
 	else
+#endif
 		writel(val, regs);
 #endif
 }
-- 
2.53.0