Messages in this thread Patch in this message | | | Subject | [PATCH] ppc64: Fix g5 hw timebase sync | From | Benjamin Herrenschmidt <> | Date | Mon, 23 May 2005 16:54:14 +1000 |
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Hi !
The hardware sync of the timebase on SMP G5s uses a black magic incantation to the i2c clock chip that was inspired from what Darwin does. However, this was an earlier version of Darwin that was ... buggy ! heh. This cause the latest models to break though when starting SMP, so it's worth fixing. Here's a new version of the incantation based on careful transcription of the said incantations as found in the latest version of apple's temple.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Index: linux-work/arch/ppc64/kernel/pmac_smp.c =================================================================== --- linux-work.orig/arch/ppc64/kernel/pmac_smp.c 2005-01-24 17:09:25.000000000 +1100 +++ linux-work/arch/ppc64/kernel/pmac_smp.c 2005-02-11 19:11:43.365862704 +1100 @@ -68,6 +68,7 @@ static void (*pmac_tb_freeze)(int freeze); static struct device_node *pmac_tb_clock_chip_host; +static u8 pmac_tb_pulsar_addr; static DEFINE_SPINLOCK(timebase_lock); static unsigned long timebase; @@ -106,12 +107,9 @@ u8 data; int rc; - /* Strangely, the device-tree says address is 0xd2, but darwin - * accesses 0xd0 ... - */ pmac_low_i2c_setmode(pmac_tb_clock_chip_host, pmac_low_i2c_mode_combined); rc = pmac_low_i2c_xfer(pmac_tb_clock_chip_host, - 0xd4 | pmac_low_i2c_read, + pmac_tb_pulsar_addr | pmac_low_i2c_read, 0x2e, &data, 1); if (rc != 0) goto bail; @@ -120,7 +118,7 @@ pmac_low_i2c_setmode(pmac_tb_clock_chip_host, pmac_low_i2c_mode_stdsub); rc = pmac_low_i2c_xfer(pmac_tb_clock_chip_host, - 0xd4 | pmac_low_i2c_write, + pmac_tb_pulsar_addr | pmac_low_i2c_write, 0x2e, &data, 1); bail: if (rc != 0) { @@ -185,6 +183,12 @@ if (ncpus <= 1) return 1; + /* HW sync only on these platforms */ + if (!machine_is_compatible("PowerMac7,2") && + !machine_is_compatible("PowerMac7,3") && + !machine_is_compatible("RackMac3,1")) + goto nohwsync; + /* Look for the clock chip */ for (cc = NULL; (cc = of_find_node_by_name(cc, "i2c-hwclock")) != NULL;) { struct device_node *p = of_get_parent(cc); @@ -198,11 +202,18 @@ goto next; switch (*reg) { case 0xd2: - pmac_tb_freeze = smp_core99_cypress_tb_freeze; - printk(KERN_INFO "Timebase clock is Cypress chip\n"); + if (device_is_compatible(cc, "pulsar-legacy-slewing")) { + pmac_tb_freeze = smp_core99_pulsar_tb_freeze; + pmac_tb_pulsar_addr = 0xd2; + printk(KERN_INFO "Timebase clock is Pulsar chip\n"); + } else if (device_is_compatible(cc, "cy28508")) { + pmac_tb_freeze = smp_core99_cypress_tb_freeze; + printk(KERN_INFO "Timebase clock is Cypress chip\n"); + } break; case 0xd4: pmac_tb_freeze = smp_core99_pulsar_tb_freeze; + pmac_tb_pulsar_addr = 0xd4; printk(KERN_INFO "Timebase clock is Pulsar chip\n"); break; } @@ -210,12 +221,15 @@ pmac_tb_clock_chip_host = p; smp_ops->give_timebase = smp_core99_give_timebase; smp_ops->take_timebase = smp_core99_take_timebase; + of_node_put(cc); + of_node_put(p); break; } next: of_node_put(p); } + nohwsync: mpic_request_ipis(); return ncpus;
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