From: Linus Walleij Date: Sat, 3 Mar 2012 20:21:13 +0000 (+0100) Subject: integrator: remove fragile delay loop from PCI code X-Git-Tag: v2012.04-rc1~85 X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=fca94c3fd5deef33442813475a5af1650f2d2830;p=oweals%2Fu-boot.git integrator: remove fragile delay loop from PCI code The reference implementation of the PCI initialization code almost everywhere contain this fragile loop of "a few usecs", and its use of volatile variables to delay a number of bus cycles is indeed uncertain. Reading the manual "Integrator/AP Users Guide", page 5-15 it is clearly stated: "Wait until 230ms after the end of the reset period before accessing V360EPC internal registers. The V360EPC supports the use of a serial configuration PROM and the software must wait for the device to detect the absence of this PROM before accessing any registers. The required delay is a function of the PCI Clock, but at the lower frequency (25MHz) is 230ms". So let's simply wait 230ms per the spec. This solves the compilation error that looked like this: pci.c: In function ‘pci_init_board’: pci.c:286:18: warning: variable ‘j’ set but not used Reported-by: Wolfgang Denk Signed-off-by: Linus Walleij --- diff --git a/board/armltd/integrator/pci.c b/board/armltd/integrator/pci.c index f040450417..8ff88fef0a 100644 --- a/board/armltd/integrator/pci.c +++ b/board/armltd/integrator/pci.c @@ -283,17 +283,14 @@ struct pci_controller integrator_hose = { void pci_init_board(void) { - volatile int i, j; struct pci_controller *hose = &integrator_hose; u16 val; /* setting this register will take the V3 out of reset */ __raw_writel(SC_PCI_PCIEN, SC_PCI); - /* wait a few usecs to settle the device and the PCI bus */ - - for (i = 0; i < 100; i++) - j = i + 1; + /* Wait for 230 ms (from spec) before accessing any V3 registers */ + mdelay(230); /* Now write the Base I/O Address Word to PHYS_PCI_V3_BASE + 0x6E */ v3_writew(V3_LB_IO_BASE, (PHYS_PCI_V3_BASE >> 16));