Hi Albert,
-----Original Message----- From: Albert ARIBAUD [mailto:albert.u.boot@aribaud.net] Sent: Monday, February 17, 2014 3:05 PM To: Badola Nikhil-B46172 Cc: u-boot@lists.denx.de; Xie Shaohui-B21989 Subject: Re: [U-Boot] [PATCH] fsl/usb: fix phy_type checking
Hi Nikhil,
On Mon, 17 Feb 2014 14:39:47 +0530, Nikhil Badola nikhil.badola@freescale.com wrote:
Strcmp should not be used to check the argument of phy_type which maybe parsed by hwconfig_subarg. Hwconfig_subarg returns part of hwconfig starting from the argument (if it has the argument) till the end of the string. Since phy_type could be either 'utmi' or 'ulpi', strncmp should be used along with length limited to 4
Not sure I understand what exact problem you are considering here. If you know that phy_type is either "utmi" or "ulpi", then there is no benefit in switching from strcmp() to strncmp() since there is no risk that strcmp() overruns any of its arguments.
[Nikhil Badola] : Strcmp() won't overrun any of its arguments but it does check NULL character at the end of both strings. Let me explain this with an example: Consider the hwconfig string to be defined as hwconfig=usb1:dr_mode=host,phy_type=utmi;fsl_ddr:bank_intlv=auto
When hwconfig string is parsed for "phy_type" sub-argument, it returns string "utmi;fsl_ddr:bank_intlv=auto" which gets stored in phy_type pointer. When strcmp() is used, then '\0' character of "utmi" string is compared with ';' of phy_type hence returning non-zero value.
Signed-off-by: Shaohui Xie Shaohui.Xie@freescale.com Signed-off-by: Nikhil Badola nikhil.badola@freescale.com
drivers/usb/host/ehci-fsl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/host/ehci-fsl.c b/drivers/usb/host/ehci-fsl.c index 45e5d6a..1ca7cf5 100644 --- a/drivers/usb/host/ehci-fsl.c +++ b/drivers/usb/host/ehci-fsl.c @@ -86,7 +86,7 @@ int ehci_hcd_init(int index, enum usb_init_type init, #endif }
- if (!strcmp(phy_type, "utmi")) {
- if (!strncmp(phy_type, "utmi", 4)) {
#if defined(CONFIG_SYS_FSL_USB_INTERNAL_UTMI_PHY) setbits_be32(&ehci->control, PHY_CLK_SEL_UTMI); setbits_be32(&ehci->control, UTMI_PHY_EN);
Amicalement, -- Albert.