RE: [U-Boot-Users] MPC8280 bus_clk
This is the code I use:
#ifdef PCI_AGENT // FIXME, do automatic checking of PCI agent mode gd->cpm_clk = gd->vco_out / 2; gd->bus_clk = gd->vco_out / (busdf + 1); gd->scc_clk = gd->vco_out / 4; gd->brg_clk = gd->vco_out / (1 << (2 * (dfbrg + 1)));
if (cp->b2c_mult > 0) { gd->cpu_clk = (gd->bus_clk * cp->b2c_mult) / 2; } else { gd->cpu_clk = clkin; } #else gd->cpm_clk = gd->vco_out / 2; gd->bus_clk = clkin; gd->scc_clk = gd->vco_out / 4; gd->brg_clk = gd->vco_out / (1 << (2 * (dfbrg + 1)));
if (cp->b2c_mult > 0) { gd->cpu_clk = (clkin * cp->b2c_mult) / 2; } else { gd->cpu_clk = clkin; } #endif
The two lines that are different are: gd->bus_clk = gd->vco_out / (busdf + 1);
gd->cpu_clk = (gd->bus_clk * cp->b2c_mult) / 2;
-----Original Message----- From: HU Chunlin [mailto:hucl606@hotmail.com] Sent: Monday, March 22, 2004 20:00 To: Rune Torgersen Cc: u-boot-users@lists.sourceforge.net Subject: RE: [U-Boot-Users] MPC8280 bus_clk
Thank you for the quick reply.
So for at least 8266 CPU running PCI agent mode, the CONFIG_8260_CLKIN definition must be set to 2 x PCI_CLK, and the bus_clk must be calculated as gd->bus_clk = gd->vco_out / (busdf + 1)?
If so, I think there must be a patch for it.
Regards, HU Chunlin
From: "Rune Torgersen" runet@innovsys.com To: "HU Chunlin" hucl606@hotmail.com Subject: RE: [U-Boot-Users] MPC8280 bus_clk Date: Mon, 22 Mar 2004 10:40:31 -0600
That is a problem for at least eht 8266 CPU when set in PCI
agent mode,
because the clockiin is then 2x the PCI clock, and is not
the bus clock
(which is multiplied up from that)
I got some information from the Technical Support
Engineering Team
of Motorola that the statement BUS_CLK == CLKIN applies
to local bus
mode only.
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Rune Torgersen