[PATCH v2 1/2] ARM: EXYNOS: Add USB HOST register definitions

Am Donnerstag 01 M?rz 2012, 17:10:52 schrieb Sangwook Lee:

On 1 March 2012 15:24, Heiko St?bner [off-list ref] wrote:

quoted

Am Donnerstag, 1. M?rz 2012, 06:38:20 schrieb Jingoo Han:

quoted

This patch adds USB HOST register definitions. The definition for
EHCI INSNREG00 regiser and corresponding bit field definitions are
added.

Signed-off-by: Sangwook Lee <redacted>
Signed-off-by: Jingoo Han <redacted>
---
v2: change the definition name from EHCI_ENA_xxx to

EHCI_INSNREG00_ENA_xxx.

quoted

arch/arm/mach-exynos/include/mach/regs-usb-host.h |   24
+++++++++++++++++++++ 1 files changed, 24 insertions(+), 0 deletions(-)

 create mode 100644 arch/arm/mach-exynos/include/mach/regs-usb-host.h

Isn't the general idea to depopulate the mach directories and make
drivers buildable across architectures?

The definitions are only used in drivers/usb/host/ehci-s5p.c [in the
second patch], so there should be no need to add another arch-header and
they could
simply be included in the driver itself or if necessary a
drivers/usb/host/ehci-s5p.h .

 I found out some code related to this burst function.

 the snip from ehci-s5pv210.c, 2.6.35 kernel

        /* Mark hardware accessible again as we are out of D3 state by now
*/
        set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
#if defined(CONFIG_ARCH_S5PV210) || defined(CONFIG_ARCH_S5P6450)
        ehci_writel(ehci, 0x000F0000, (void __iomem *)ehci->caps + 0x90);
#endif

#if defined(CONFIG_ARCH_S5PV310)
        ehci_writel(ehci, 0x03C00000, (void __iomem *)ehci->caps + 0x90);
#endif
        if (ehci_readl(ehci, &ehci->regs->configured_flag) == FLAG_CF) {

From this code, this burst function seems to be depending on CPUs,
The driver by itself is not good idea because echi-s5p.c will have defined.

The current driver in mainline does not contain these ifdefs and this also 
should not change. What would happen in the code above if ARCH_S5PV210 and 
ARCH_S5PV310 are selected?

As providing support for more than one SoC in a kernel image is one of the 
current targets, architecture dependant stuff like the code above should 
probably be detected at runtime and definitly not compile-time.

Which is the better place to pus this CPU specific definition either
drivers/usb/host/ehci-s5p.h is
or mach/xx.h or  include/linux/usb/xxx.h ?  I am not clear about this.

As I understand it, drivers should be compileable even if the underlying 
architecture is not selected and hence mustn't depend on architecure code.

Use-cases are for example compile-testing all usb-host drivers at once during 
some sort of rework, or the multi-arch kernel mentioned above.

But I really do not see why these defines you're adding cannot simply live 
inside the ehci-s5p.c . For example take a look at 
drivers/usb/gadget/s3c-hsudc.c . This driver also contains its private defines 
without the need for another header.

quoted

quoted

diff --git a/arch/arm/mach-exynos/include/mach/regs-usb-host.h

b/arch/arm/mach-exynos/include/mach/regs-usb-host.h new file mode
100644 index 0000000..572b7d4

--- /dev/null
+++ b/arch/arm/mach-exynos/include/mach/regs-usb-host.h

@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2012 Samsung Electronics Co.Ltd
+ *           http://www.samsung.com
+ *
+ * EXYNOS - USB HOST register definitions
+ *
+ * This program is free software; you can redistribute it and/or

modify + * it under the terms of the GNU General Public License
version 2 as + * published by the Free Software Foundation.
+ */
+
+#ifndef __REGS_USB_HOST_H
+#define __REGS_USB_HOST_H __FILE__
+
+#define EHCI_INSNREG00(base)                 (base + 0x90)
+#define EHCI_INSNREG00_ENA_INCR16            (0x1 << 25)
+#define EHCI_INSNREG00_ENA_INCR8             (0x1 << 24)
+#define EHCI_INSNREG00_ENA_INCR4             (0x1 << 23)
+#define EHCI_INSNREG00_ENA_INCRX_ALIGN               (0x1 << 22)
+#define EHCI_INSNREG00_ENABLE_DMA_BURST      \
+     (EHCI_INSNREG00_ENA_INCR16 | EHCI_INSNREG00_ENA_INCR8 | \
+      EHCI_INSNREG00_ENA_INCR4 | EHCI_INSNREG00_ENA_INCRX_ALIGN)
+
+#endif /* __REGS_USB_HOST_H */

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