Commit dc9aa43c authored by Al Cooper's avatar Al Cooper Committed by Kishon Vijay Abraham I
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phy: usb: EHCI DMA may lose a burst of DMA data for 7255xA0 family 



When the EHCI controller received a 512 byte USB packet that
had to be broken into 2 256 byte bursts across the SCB bus AND
there was a following 512 byte USB packet, the second burst of
data from the first packet was sometimes being lost. If the
burst size was changed to 128 bytes via the EBR_SCB_SIZE field
in the USB_CTRL_EBRIDGE register we'd see the 4th 128 byte burst
of the first packet being lost. This problem became much worse
if other threads were running that accessed memory, like a memcpy
test. Setting the EBR_SCB_SIZE to 512, which prevents breaking
the EHCI USB packet (max size of 512 bytes) into bursts, fixed
the problem.

Signed-off-by: default avatarAl Cooper <alcooperx@gmail.com>
Reviewed-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
parent d0312fdb

drivers/phy/broadcom/phy-brcm-usb-init.c

+13 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ 
#define   USB_CTRL_PLL_CTL_PLL_IDDQ_PWRDN_MASK		0x80000000 /* option */

#define USB_CTRL_EBRIDGE		0x0c

#define   USB_CTRL_EBRIDGE_ESTOP_SCB_REQ_MASK		0x00020000 /* option */

#define   USB_CTRL_EBRIDGE_EBR_SCB_SIZE_MASK		0x00000f80 /* option */

#define USB_CTRL_OBRIDGE		0x10

#define   USB_CTRL_OBRIDGE_LS_KEEP_ALIVE_MASK		0x08000000

#define USB_CTRL_MDIO			0x14
@@ -176,6 +177,7 @@ static const struct id_to_type id_to_type_table[] = { 
	{ 0x33900000, BRCM_FAMILY_3390A0 },

	{ 0x72500010, BRCM_FAMILY_7250B0 },

	{ 0x72600000, BRCM_FAMILY_7260A0 },

	{ 0x72550000, BRCM_FAMILY_7260A0 },

	{ 0x72680000, BRCM_FAMILY_7271A0 },

	{ 0x72710000, BRCM_FAMILY_7271A0 },

	{ 0x73640000, BRCM_FAMILY_7364A0 },
@@ -948,6 +950,17 @@ void brcm_usb_init_eohci(struct brcm_usb_init_params *params) 
	if (params->selected_family == BRCM_FAMILY_7271A0)

		/* Enable LS keep alive fix for certain keyboards */

		USB_CTRL_SET(ctrl, OBRIDGE, LS_KEEP_ALIVE);



	if (params->family_id == 0x72550000) {

		/*

		 * Make the burst size 512 bytes to fix a hardware bug

		 * on the 7255a0. See HW7255-24.

		 */

		reg = brcmusb_readl(USB_CTRL_REG(ctrl, EBRIDGE));

		reg &= ~USB_CTRL_MASK(EBRIDGE, EBR_SCB_SIZE);

		reg |= 0x800;

		brcmusb_writel(reg, USB_CTRL_REG(ctrl, EBRIDGE));

	}

}



void brcm_usb_init_xhci(struct brcm_usb_init_params *params)