Re: [PATCH 2/3 v4] musb: add musb support for AM35x

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Hello.

Ajay Kumar Gupta wrote:

AM35x has musb interface and uses CPPI4.1 DMA engine.
Current patch supports only PIO mode. DMA support can be
added later once basic CPPI4.1 DMA patch is accepted.

Also added USB_MUSB_AM35X which is required to differentiate musb ips
between OMAP3x and AM35x. This config would be used to for below
purposes,
        - Select am35x.c instead of omap2430.c for compilation
          at drivers/usb/musb directory. Please note there are
          significant differneces in these two files as musb ip
          in quite different on AM35x.
        - Select workaround codes applicable for AM35x musb issues.
          one such workaround is for bytewise read issue on AM35x.

Signed-off-by: Ajay Kumar Gupta <ajay.gupta@xxxxxx>

[...]

diff --git a/drivers/usb/musb/Kconfig b/drivers/usb/musb/Kconfig
index 1dd21c2..0941a32 100644
--- a/drivers/usb/musb/Kconfig
+++ b/drivers/usb/musb/Kconfig
@@ -60,6 +60,17 @@ comment "OMAP 44xx high speed USB support"
 comment "Blackfin high speed USB Support"
 	depends on USB_MUSB_HDRC && ((BF54x && !BF544) || (BF52x && !BF522 && !BF523))
+config USB_MUSB_AM35X
+	boolean "AM35X MUSB support"
+	depends on USB_MUSB_HDRC && MACH_OMAP3517EVM

   As I've already said, depending on the board type won't scale... :-(

+	select NOP_USB_XCEIV
+	default y
+	help
+	  Select this option if your platform is based on AM35x. As
+	  AM35x has an updated MUSB with CPPI4.1 DMA so this config
+	  is introduced to differentiate musb ip between OMAP3x and
+	  AM35x platforms.

   OK, but why it's made visible?

diff --git a/drivers/usb/musb/am35x.c b/drivers/usb/musb/am35x.c
new file mode 100644
index 0000000..ee0c104
--- /dev/null
+++ b/drivers/usb/musb/am35x.c
@@ -0,0 +1,510 @@
+/*
+ * Texas Instruments AM35x "glue layer"
+ *
+ * Copyright (c) 2010, by Texas Instruments
+ *
+ * Based on the DA8xx "glue layer" code.
+ * Copyright (C) 2005-2006 by Texas Instruments

There's no code by TI in the DA8xx layer -- that copyright comes from the DaVinci code.

+ * Copyright (c) 2008, MontaVista Software, Inc. <source@xxxxxxxxxx>

   I've extended it to 2008-2009 (and should have to 2010 :-).

+/* USB interrupt register bits */
+#define USB_INTR_USB_SHIFT	16
+#define USB_INTR_USB_MASK	(0x1ff << USB_INTR_USB_SHIFT)

   Don't seem like good names (USB_ repeated twice)...

[...]

+int __init musb_platform_init(struct musb *musb, void *board_data)
+{
+	void __iomem *reg_base = musb->ctrl_base;
+	struct clk *otg_fck;
+	u32 rev, lvl_intr, sw_reset;
+	int status;
+
+	musb->mregs += USB_MENTOR_CORE_OFFSET;
+
+	if (musb->set_clock)
+		musb->set_clock(musb->clock, 1);

   OMAP doesn't use plat->set_clock anymore, does it?

+	else
+		clk_enable(musb->clock);
+	DBG(2, "usbotg_ck=%lud\n", clk_get_rate(musb->clock));
+
+	otg_fck = clk_get(musb->controller, "fck");
+	if (IS_ERR(otg_fck)) {
+		status = PTR_ERR(otg_fck);
+		otg_fck = NULL;

   This assignment does not seem necessary.

+		goto exit0;
+	}
[...]
+exit1:
+	clk_disable(otg_fck);
+exit0:
+	clk_disable(musb->clock);
+	return status;
+}
+
+int musb_platform_exit(struct musb *musb)
+{
+	struct clk *otg_fck;
+
+	if (is_host_enabled(musb))
+		del_timer_sync(&otg_workaround);
+
+	phy_off();
+
+	otg_put_transceiver(musb->xceiv);
+	usb_nop_xceiv_unregister();
+
+	if (musb->set_clock)
+		musb->set_clock(musb->clock, 0);

   Looks like it may be dropped...

+	else
+		clk_disable(musb->clock);
+
+	otg_fck = clk_get(musb->controller, "fck");

Isn't it better to store this in some static variable? I don't think there's or there'll be multiple instances of MUSB on AM35x...

+	if (IS_ERR(otg_fck)) {
+		DBG(2, "clk_get() failed for otg_fck.\n");
+	} else {
+		clk_put(otg_fck);
+		clk_put(otg_fck);
+		clk_disable(otg_fck);
+	}
+
+	return 0;
+}

WBR, Sergei
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