On 02/12/2024 10:29, Jean-Michel Hautbois wrote:
This patch series adds support for DMA timers for the M5441x coldfire
family. The aim is to provide finer scheduler resolution and support for
high-resolution timers.
The first patch fixes the clocks and a typo. The second one is the
timers support addition. As there is no device tree, I did not use
TIMER_OF_DECLARE().
I forgot to mention the result on a real M544118 board !
With PIT timer:
bash-5.2# cyclictest -p 80 -m -q -l 10000
WARN: stat /dev/cpu_dma_latency failed: No such file or directory
WARN: High resolution timers not available
T: 0 ( 231) P:80 I:1000 C: 10000 Min: 277 Act: 1965 Avg: 1437 Max:
2023
With this driver and the following declaration in m5441x.c:
static struct resource mcf_dmatmr2_resource[] = {
[0] = {
.start = MCFDMATIMER_BASE2,
.end = MCFDMATIMER_BASE2 + 0xf,
.flags = IORESOURCE_MEM,
},
[1] = {
.start = MCFDMATIMER_IRQ_DTIM2,
.end = MCFDMATIMER_IRQ_DTIM2,
.flags = IORESOURCE_IRQ,
},
[2] = {
.start = MCFDMATIMER_IRQ_PRIO2,
.end = MCFDMATIMER_IRQ_PRIO2,
.flags = IORESOURCE_REG,
.name = "prio_reg",
}
};
static struct platform_device mcf_dmatmr2 = {
.name = "mcftmr",
.id = 2,
.num_resources = ARRAY_SIZE(mcf_dmatmr2_resource),
.resource = mcf_dmatmr2_resource,
};
bash-5.2# cyclictest -p 80 -m -q -l 10000 -R
WARN: stat /dev/cpu_dma_latency failed: No such file or directory
WARN: reported clock resolution: 1 nsec
WARN: measured clock resolution approximately: 2376 nsec
T: 0 ( 243) P:80 I:1000 C: 10000 Min: 104 Act: 125 Avg: 129 Max:
239
I don't know why the reported resolution is 1ns and not 8ns but it is
not a big issue I suppose :-) ?
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@xxxxxxxxxx>
---
Jean-Michel Hautbois (2):
m68k: coldfire: Use proper clock rate for timers
m68k: m5441x: Add DMA timer support
MAINTAINERS | 6 +
arch/m68k/coldfire/m5441x.c | 20 +--
arch/m68k/include/asm/m5441xsim.h | 18 +++
drivers/clocksource/Kconfig | 9 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/mcf_dma_timer.c | 240 ++++++++++++++++++++++++++++++++++++
6 files changed, 284 insertions(+), 10 deletions(-)
---
base-commit: e3f432391d55ec21274bd16a04659b4a24678535
change-id: 20241202-m5441x_dma_tmr-d969f4cc30a8
Best regards,
