On Fri, Apr 1, 2016 at 5:44 PM, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
> From: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
>
> Currently tmio_mmc assumes that the input clock frequency is fixed and
> only its own clock divider can be changed. This is not true in the
> case of sh_mobile_sdhi; we can use the clock API to change it.
>
> In tmio_mmc:
> - Delegate setting of f_min from tmio to the clk_enable operation (if
> implemented), as it can be smaller than f_max / 512
> - Add an optional clk_update operation called from tmio_mmc_set_clock()
> that updates the input clock frequency
> - Rename tmio_mmc_clk_update() to tmio_mmc_clk_enable(), to avoid
> confusion with the clk_update operation
>
> In sh_mobile_sdhi:
> - Make the setting of f_max conditional; it should be set through the
> max-frequency property in the device tree in future
> - Set f_min based on the input clock's minimum frequency
> - Implement the clk_update operation, selecting the best input clock
> frequency for the bus frequency that's wanted
>
> sh_mobile_sdhi_clk_update() is loosely based on Kuninori Morimoto's work
> in sh_mmcif.
>
> Signed-off-by: Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
This is now commit 2e21101df4fe8bdc ("mmc: tmio, sh_mobile_sdhi: Add support
for variable input clock frequency") in the next branch of Ulf's mmc.git.
1. The SDHI/MMC clocks now run much slower than before. Perhaps this is
intentional, and a consequence of finding the best way to drive the SD
card at the target frequency?
2. On r8a7740, the situation is worse: the HP ("High-speed Peripheral")
clock is also scaled down from 99 MHz to 12.375 MHz.
As the HP clock is the parent of lots of on-chip devices, this may affect
performance for all of them.
On r8a73a4, r8a7791, and sh73a0, the SDHI clocks are children of the pll1_div2
clocks, which are fixed.
On r8a7740, the SDHI and MMC clocks are children of the HP clock,
which is also scaled down, affecting all other siblings.
dmesg and /sys/kernel/debug/clk/clk_summary differences below.
r8a73a4/ape6evm
---------------
-sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 clock rate 88 MHz
+sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 max clock rate 88 MHz
-sh_mobile_sdhi ee120000.sd: mmc1 base at 0xee120000 clock rate 12 MHz
+sh_mobile_sdhi ee120000.sd: mmc1 base at 0xee120000 max clock rate 12 MHz
clock enable_cnt prepare_cnt rate accuracy phase
-------------------------------------------------------------------------
- sdhi1ck 1 1 12500000 0 0
- sdhi1 2 2 12500000 0 0
- sdhi0ck 1 1 88888888 0 0
- sdhi0 1 2 88888888 0 0
+ sdhi1ck 1 1 12698412 0 0
+ sdhi1 2 2 12698412 0 0
+ sdhi0ck 1 1 12698412 0 0
+ sdhi0 1 2 12698412 0 0
r8a7791/koelsch
---------------
-sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 clock rate 97 MHz
+sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 max clock rate 97 MHz
-sh_mobile_sdhi ee140000.sd: mmc1 base at 0xee140000 clock rate 48 MHz
+sh_mobile_sdhi ee140000.sd: mmc1 base at 0xee140000 max clock rate 48 MHz
-sh_mobile_sdhi ee160000.sd: mmc2 base at 0xee160000 clock rate 48 MHz
+sh_mobile_sdhi ee160000.sd: mmc2 base at 0xee160000 max clock rate 48 MHz
mmc0 0 0 12187500 0 0
mmcif0 0 0 12187500 0 0
- sd3 1 1 48750000 0 0
- sdhi2 1 2 48750000 0 0
- sd2 1 1 48750000 0 0
- sdhi1 1 2 48750000 0 0
+ sd3 1 1 12786885 0 0
+ sdhi2 1 2 12786885 0 0
+ sd2 1 1 12786885 0 0
+ sdhi1 1 2 12786885 0 0
sh73a0/kzm9g
------------
-sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 clock rate 69 MHz
+sh_mobile_sdhi ee100000.sd: mmc0 base at 0xee100000 max clock rate 69 MHz
-sh_mobile_sdhi ee140000.sd: mmc1 base at 0xee140000 clock rate 69 MHz
+sh_mobile_sdhi ee140000.sd: mmc1 base at 0xee140000 max clock rate 69 MHz
- sdhi2ck 1 1 69333333 0 0
- sdhi2 2 2 69333333 0 0
+ sdhi2ck 1 1 12734693 0 0
+ sdhi2 2 2 12734693 0 0
sdhi1ck 0 0 69333333 0 0
sdhi1 0 0 69333333 0 0
- sdhi0ck 1 1 69333333 0 0
- sdhi0 1 2 69333333 0 0
+ sdhi0ck 1 1 12734693 0 0
+ sdhi0 1 2 12734693 0 0
r8a7740/armadillo
-----------------
-sh_mobile_sdhi e6850000.sd: mmc0 base at 0xe6850000 clock rate 99 MHz
+sh_mobile_sdhi e6850000.sd: mmc0 base at 0xe6850000 max clock rate 99 MHz
-sh_mmcif e6bd0000.mmc: Chip version 0x0003, clock rate 99MHz
+sh_mmcif e6bd0000.mmc: Chip version 0x0003, clock rate 12MHz
- hp 4 6 99000000 0 0
- tpu0 0 1 99000000 0 0
- gether 1 1 99000000 0 0
- mmc 2 2 99000000 0 0
- sdhi1 0 0 99000000 0 0
- sdhi0 1 2 99000000 0 0
- usbf 0 0 99000000 0 0
- fsi 0 1 99000000 0 0
- usbdmac 0 0 99000000 0 0
- dmac3 0 0 99000000 0 0
- dmac2 0 0 99000000 0 0
- dmac1 0 0 99000000 0 0
- intca 4 4 99000000 0 0
- usphy 0 0 99000000 0 0
- usbfunc 0 0 99000000 0 0
- sdhi2 0 0 99000000 0 0
- usbhost 0 0 99000000 0 0
+ hp 4 6 12375000 0 0
+ tpu0 0 1 12375000 0 0
+ gether 1 1 12375000 0 0
+ mmc 2 2 12375000 0 0
+ sdhi1 0 0 12375000 0 0
+ sdhi0 1 2 12375000 0 0
+ usbf 0 0 12375000 0 0
+ fsi 0 1 12375000 0 0
+ usbdmac 0 0 12375000 0 0
+ dmac3 0 0 12375000 0 0
+ dmac2 0 0 12375000 0 0
+ dmac1 0 0 12375000 0 0
+ intca 4 4 12375000 0 0
+ usphy 0 0 12375000 0 0
+ usbfunc 0 0 12375000 0 0
+ sdhi2 0 0 12375000 0 0
+ usbhost 0 0 12375000 0 0
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
