From 3f02a957d5eb0eeb01207a799086f2b347077f71 Mon Sep 17 00:00:00 2001 From: Enrico Scholz Date: Thu, 17 Jul 2008 20:09:30 +0200 Subject: usb: ISP1760: improve pre-fetch timing ISP1760 requires a delay of 90ns between programming the address and reading the data. Current driver solves this by a mdelay(1) which is very heavy weighted and slow. This patch applies the workaround from the ISP1760 FAQ by using two different banks for PTD and payload data and using a common wait for them. This wait is done by an additional ISP1760 access (whose timing constraints guarantee the 90ns delay). This improves speed when reading from an USB stick from: $ time dd if=/dev/sda of=/dev/zero bs=65536 count=1638 real 1m 15.43s user 0m 0.44s sys 0m 39.46s to $ time dd if=/dev/sda of=/dev/zero bs=65536 count=1638 real 0m 18.53s user 0m 0.16s sys 0m 12.97s [bigeasy@linutronix.de: fixed comment formating, moved define into header file, obey 80 char rule] Signed-off-by: Enrico Scholz Signed-off-by: Sebastian Siewior Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/isp1760-hcd.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/usb/host/isp1760-hcd.h') diff --git a/drivers/usb/host/isp1760-hcd.h b/drivers/usb/host/isp1760-hcd.h index 6473dd86993c..3c61cd51cbb8 100644 --- a/drivers/usb/host/isp1760-hcd.h +++ b/drivers/usb/host/isp1760-hcd.h @@ -54,6 +54,8 @@ void deinit_kmem_cache(void); #define BUFFER_MAP 0x7 #define HC_MEMORY_REG 0x33c +#define ISP_BANK(x) ((x) << 16) + #define HC_PORT1_CTRL 0x374 #define PORT1_POWER (3 << 3) #define PORT1_INIT1 (1 << 7) -- cgit v1.2.3