On Sat, 26 May 2018, Guenter Roeck wrote: > As of commit 205e1b7f51e4 ("dma-mapping: warn when there is no > coherent_dma_mask") the NatSemi SONIC Ethernet driver is issuing the > following warning on driver initialization on Macintosh q800 systems. > > SONIC ethernet @50f0a000, MAC 08:00:07:12:34:56, IRQ 3 > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 > macsonic_init+0x6a/0x15a > Modules linked in: > CPU: 0 PID: 1 Comm: swapper Not tainted 4.17.0-rc6-mac-00286-g527f47c #1 > Stack from 0781fdd8: > 0781fdd8 003615b3 000181ba 000005c4 07a24cbc 00000000 00000000 > 000020e8 > 07a24800 002c196c 0001824e 00334c06 00000204 001f782a 00000009 00000000 > 00000000 003358d9 001f782a 00334c06 00000204 00000003 00000000 07a24800 > 002b5cb6 000372ec 001f8b1a 07a24800 00359203 50f0a000 07a14a48 00000003 > 00000000 07845c0a 0039dcca 003c835c 003c835c 0035b924 001c19de 07845c00 > 07845c0a 0039dcca 001c06dc 07845c0a 0781fed8 00000007 0054d040 07845c0a > Call Trace: [<000181ba>] __warn+0xc0/0xc2 > [<000020e8>] do_one_initcall+0x0/0x140 > [<0001824e>] warn_slowpath_null+0x26/0x2c > [<001f782a>] macsonic_init+0x6a/0x15a > [<001f782a>] macsonic_init+0x6a/0x15a > [<002b5cb6>] memcmp+0x0/0x2a > [<000372ec>] printk+0x0/0x18 > [<001f8b1a>] mac_sonic_platform_probe+0x380/0x404 > > As per the warning the coherent_dma_mask is not set on this device. > There is nothing special about the DMA memory coherency on this hardware > so we can just set the mask to 32bits in the platform data for the FEC > ethernet devices. > > Signed-off-by: Guenter Roeck <li...@roeck-us.net>
Acked-by: Finn Thain <fth...@telegraphics.com.au> Geert, assuming that Guenter's patch is acceptable, would you also accept a similar patch for the "macmace" platform device? > --- > Modeled after f61e64310b75 ("m68k: set dma and coherent masks for platform > FEC ethernets"). > > RFC: Is "nothing special about the DMA memory coherency" correect ? > As I understand it, "cache-coherence" is meaningless unless you have multiple CPU cores and caches. If there's only one CPU core, its cache can't be said to be "coherent" or "non-coherent". Moreover, DMA (direct memory access) concerns an IO device and a memory, not a cache, so the term "coherent dma" is bogus IMHO. -- > arch/m68k/mac/config.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/arch/m68k/mac/config.c b/arch/m68k/mac/config.c > index 0c3275aa0197..8e0476daddb8 100644 > --- a/arch/m68k/mac/config.c > +++ b/arch/m68k/mac/config.c > @@ -17,6 +17,7 @@ > #include <linux/tty.h> > #include <linux/console.h> > #include <linux/interrupt.h> > +#include <linux/dma-mapping.h> > /* keyb */ > #include <linux/random.h> > #include <linux/delay.h> > @@ -971,6 +972,15 @@ static const struct resource mac_scsi_ccl_rsrc[] > __initconst = { > }, > }; > > +static struct platform_device macsonic_dev = { > + .name = "macsonic", > + .id = -1, > + .dev = { > + .dma_mask = &macsonic_dev.dev.coherent_dma_mask, > + .coherent_dma_mask = DMA_BIT_MASK(32), > + }, > +}; > + > int __init mac_platform_init(void) > { > u8 *swim_base; > @@ -1088,7 +1098,7 @@ int __init mac_platform_init(void) > > if (macintosh_config->ether_type == MAC_ETHER_SONIC || > macintosh_config->expansion_type == MAC_EXP_PDS_COMM) > - platform_device_register_simple("macsonic", -1, NULL, 0); > + platform_device_register(&macsonic_dev); > > if (macintosh_config->expansion_type == MAC_EXP_PDS || > macintosh_config->expansion_type == MAC_EXP_PDS_COMM) > -- > 2.7.4 >