Maybe, but bus_dmamap_load() only lets you map one buffer at a time.
I want to map a bunch of little buffers, and the API doesn't let me
do that. And I don't want to change the API, because that would mean
modifying busdma_machdep.c on each platform, which is a hell that I
would rather
My understanding is that you need a dmamap for every buffer that you want
to map into bus space.
You need one dmamap for each independantly manageable mapping. A
single mapping may result in a long list of segments, regardless
of whether you have a single KVA buffer or multiple KVA
My understanding is that you need a dmamap for every buffer that you want
to map into bus space.
You need one dmamap for each independantly manageable mapping. A
single mapping may result in a long list of segments, regardless
of whether you have a single KVA buffer or multiple KVA
The fact that the data is less than a page in size matters little
to the bus dma concept. In other words, how is this packet presented
to the hardware? Does it care that all of the component pieces are
PAGE_SIZE in length? Probably not. It just wants the list of
address/length pairs
The fact that the data is less than a page in size matters little
to the bus dma concept. In other words, how is this packet presented
to the hardware? Does it care that all of the component pieces are
PAGE_SIZE in length? Probably not. It just wants the list of
address/length pairs
Correction.
This sample:
if (bus_dma_tag_create(pci-parent_dmat, PAGE_SIZE, lim,
BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL, len, 1,
BUS_SPACE_MAXSIZE_32BIT, 0, pci-cntrol_dmat) != 0) {
isp_prt(isp, ISP_LOGERR,
Yay!
The current suggestion is fine except that each platform might have a more
efficient, or even required, actual h/w mechanism for mapping mbufs.
I'd also be a little concerned with the way you're overloading stuff into mbuf
itself- but I'm a little shakier on this.
Finally- why not make
Another thing- maybe I'm confused- but I still don't see why you want to
require the creating of a map each time you want to load an mbuf
chain. Wouldn't it be better and more efficient to let the driver decide when
and where the map is created and just use the common code for loads/unloads?
On
Another thing- maybe I'm confused- but I still don't see why you want to
require the creating of a map each time you want to load an mbuf
chain. Wouldn't it be better and more efficient to let the driver decide when
and where the map is created and just use the common code for
On Mon, 20 Aug 2001, Bill Paul wrote:
Every hear the phrase you get what you pay for? The API isn't all that
clear, and we don't have a man page or document that describes in detail
how to use it properly. Rather than whining about that, I decided to
tinker with it and Use The Source, Luke
Correction.
This sample:
if (bus_dma_tag_create(pci-parent_dmat, PAGE_SIZE, lim,
BUS_SPACE_MAXADDR, BUS_SPACE_MAXADDR, NULL, NULL, len, 1,
BUS_SPACE_MAXSIZE_32BIT, 0, pci-cntrol_dmat) != 0) {
isp_prt(isp, ISP_LOGERR,
Every hear the phrase you get what you pay for? The API isn't all that
clear, and we don't have a man page or document that describes in detail
how to use it properly. Rather than whining about that, I decided to
tinker with it and Use The Source, Luke (tm). This is the result.
Fair enough.
My
12 matches
Mail list logo
