* sama5d: using the ebi interface from another driver
@ 2018-11-02 13:35 Jean-Michel Hautbois
2018-11-05 9:19 ` Ludovic Desroches
2018-11-06 9:57 ` Alexander Dahl
0 siblings, 2 replies; 4+ messages in thread
From: Jean-Michel Hautbois @ 2018-11-02 13:35 UTC (permalink / raw)
To: boris.brezillon; +Cc: linux-arm-kernel, linux-kernel, Nicolas Ferre
Hi all,
I have a custom board based on a sama5d3 chip. The SoC is connected to
2 pef24628 SHDSL transceivers, the first one on ebi@40000000 and the
second one on ebi@50000000.
I tried to write a basic char driver, using request_mem_region and
ioremap but I can't read or write into the device.
I have to say that the driver is based on a proprietary one, and
tested years ago on a PowerPC board.
Then, after looking into deeper details in the datasheet I understand
it is connected through EBI and it sounds not so easy :D.
I would appreciate some help/pointers on this, as there is (at least,
I could find) few documentation on how to use it except for NAND
cases.
I have something like that in my DTS, but not sure this is the correct
way to do it :
ebi: ebi@10000000 {
pinctrl-0 = <&pinctrl_ebi_nand_addr>;
pinctrl-names = "default";
status = "okay";
dsp0: pef24628@1 {
status = "okay";
compatible = "intel,pef24628";
#address-cells = <1>;
#size-cells = <1>;
reg = <0x1 0x0 0x8000>;
pinctrl-0 = <&pinctrl_dsp_cs1>;
};
dsp1: pef24628@2 {
status = "okay";
compatible = "intel,pef24628";
#address-cells = <1>;
#size-cells = <1>;
reg = <0x2 0x0 0x8000>;
pinctrl-0 = <&pinctrl_dsp_cs2>;
};
nand_controller: nand-controller {
status = "okay";
nand@3 {
reg = <0x3 0x0 0x2>;
atmel,rb = <0>;
nand-bus-width = <8>;
nand-ecc-mode = "hw";
nand-ecc-strength = <4>;
nand-ecc-step-size = <512>;
nand-on-flash-bbt;
label = "atmel_nand";
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
[...]
};
};
};
The pinctrl for ebi should probably be changed however, I am wondering
how the (platform ?) driver can access the adress ? Should it parse
itself the parent, and find range, etc. Or is there an accessor for it
?
Maybe can I just manually toggle the CS GPIO, and don't try to make
anything more complex than what it should be ? The driver should not
be atmel dependant...
Thanks !
JM
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: sama5d: using the ebi interface from another driver
2018-11-02 13:35 sama5d: using the ebi interface from another driver Jean-Michel Hautbois
@ 2018-11-05 9:19 ` Ludovic Desroches
2018-11-06 9:57 ` Alexander Dahl
1 sibling, 0 replies; 4+ messages in thread
From: Ludovic Desroches @ 2018-11-05 9:19 UTC (permalink / raw)
To: Jean-Michel Hautbois
Cc: boris.brezillon, Nicolas Ferre, linux-kernel, linux-arm-kernel
Hi Jean-Michel,
On Fri, Nov 02, 2018 at 02:35:26PM +0100, Jean-Michel Hautbois wrote:
> Hi all,
>
> I have a custom board based on a sama5d3 chip. The SoC is connected to
> 2 pef24628 SHDSL transceivers, the first one on ebi@40000000 and the
> second one on ebi@50000000.
> I tried to write a basic char driver, using request_mem_region and
> ioremap but I can't read or write into the device.
> I have to say that the driver is based on a proprietary one, and
> tested years ago on a PowerPC board.
>
> Then, after looking into deeper details in the datasheet I understand
> it is connected through EBI and it sounds not so easy :D.
>
> I would appreciate some help/pointers on this, as there is (at least,
> I could find) few documentation on how to use it except for NAND
> cases.
>
> I have something like that in my DTS, but not sure this is the correct
> way to do it :
>
> ebi: ebi@10000000 {
> pinctrl-0 = <&pinctrl_ebi_nand_addr>;
> pinctrl-names = "default";
> status = "okay";
>
> dsp0: pef24628@1 {
> status = "okay";
> compatible = "intel,pef24628";
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0x1 0x0 0x8000>;
> pinctrl-0 = <&pinctrl_dsp_cs1>;
> };
>
> dsp1: pef24628@2 {
> status = "okay";
> compatible = "intel,pef24628";
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0x2 0x0 0x8000>;
> pinctrl-0 = <&pinctrl_dsp_cs2>;
> };
>
> nand_controller: nand-controller {
> status = "okay";
>
> nand@3 {
> reg = <0x3 0x0 0x2>;
> atmel,rb = <0>;
> nand-bus-width = <8>;
> nand-ecc-mode = "hw";
> nand-ecc-strength = <4>;
> nand-ecc-step-size = <512>;
> nand-on-flash-bbt;
> label = "atmel_nand";
>
> partitions {
> compatible = "fixed-partitions";
> #address-cells = <1>;
> #size-cells = <1>;
> [...]
> };
> };
> };
>
> The pinctrl for ebi should probably be changed however, I am wondering
> how the (platform ?) driver can access the adress ? Should it parse
> itself the parent, and find range, etc. Or is there an accessor for it
> ?
At first look, your DT seems correct. You have nothing special to do,
the usual platform_get_resource() and devm_ioremap_resource() calls are enough.
The address translation should be done automatically according to ranges
property.
Another hint is to check and specify the signals timings.
Regards
Ludovic
>
> Maybe can I just manually toggle the CS GPIO, and don't try to make
> anything more complex than what it should be ? The driver should not
> be atmel dependant...
>
> Thanks !
> JM
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: sama5d: using the ebi interface from another driver
2018-11-02 13:35 sama5d: using the ebi interface from another driver Jean-Michel Hautbois
2018-11-05 9:19 ` Ludovic Desroches
@ 2018-11-06 9:57 ` Alexander Dahl
2018-11-07 17:07 ` Jean-Michel Hautbois
1 sibling, 1 reply; 4+ messages in thread
From: Alexander Dahl @ 2018-11-06 9:57 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Jean-Michel Hautbois, boris.brezillon, Nicolas Ferre, linux-kernel
Hei hei,
Am Freitag, 2. November 2018, 14:35:26 CET schrieb Jean-Michel Hautbois:
> Then, after looking into deeper details in the datasheet I understand
> it is connected through EBI and it sounds not so easy :D.
Did you read docs on that? You'll find the binding docs here:
Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt
> I would appreciate some help/pointers on this, as there is (at least,
> I could find) few documentation on how to use it except for NAND
> cases.
I use EBI with at91sam9g20 and custom FPGA on CS5 (0x6000000) and CS7
(0x8000000).
> I have something like that in my DTS, but not sure this is the correct
> way to do it :
>
> ebi: ebi@10000000 {
> pinctrl-0 = <&pinctrl_ebi_nand_addr>;
> pinctrl-names = "default";
> status = "okay";
>
> dsp0: pef24628@1 {
> status = "okay";
> compatible = "intel,pef24628";
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0x1 0x0 0x8000>;
> pinctrl-0 = <&pinctrl_dsp_cs1>;
> };
>
> dsp1: pef24628@2 {
> status = "okay";
> compatible = "intel,pef24628";
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0x2 0x0 0x8000>;
> pinctrl-0 = <&pinctrl_dsp_cs2>;
> };
I'm not sure about those 'reg' settings. IIRC the first should correspond to
the CS line, on at91sam9g20 the 0x40000000 would be CS3 (which is used by
NAND, like in the dts snippet you posted) and 0x50000000 would be CS4. Are CS1
(which is used by SD-RAM) and CS2 free to use on sama5d3?
Maybe that's different on sama5d3? I would check it again.
> The pinctrl for ebi should probably be changed however, I am wondering
> how the (platform ?) driver can access the adress ? Should it parse
> itself the parent, and find range, etc. Or is there an accessor for it
> ?
Probably. This is what I have for the at91sam9g20:
pinctrl@fffff400 {
ebi {
pinctrl_ebi_cs5: ebi-cs5-0 {
atmel,pins =
<AT91_PIOC 9 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;
};
pinctrl_ebi_cs7: ebi-cs7-0 {
atmel,pins =
<AT91_PIOC 12 AT91_PERIPH_B AT91_PINCTRL_PULL_UP>;
};
pinctrl_ebi_nwait: ebi-nwait-0 {
atmel,pins =
<AT91_PIOC 15 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;
};
};
};
> Maybe can I just manually toggle the CS GPIO, and don't try to make
> anything more complex than what it should be ? The driver should not
> be atmel dependant...
As Ludovic said, you should check the settings and timings for the external
memory interface. This could look more or less similar to that:
foo_bar: foo-bar@5,0 {
status = "okay";
pinctrl-0 = <&pinctrl_ebi_cs5>;
pinctrl-names = "default";
reg = <0x5 0x0 0x80000>;
atmel,smc-bus-width = <8>;
atmel,smc-read-mode = "nrd";
atmel,smc-write-mode = "nwe";
atmel,smc-exnw-mode = "ready";
atmel,smc-ncs-rd-setup-ns = <7>;
atmel,smc-nrd-setup-ns = <7>;
atmel,smc-ncs-wr-setup-ns = <7>;
atmel,smc-nwe-setup-ns = <7>;
atmel,smc-ncs-rd-pulse-ns = <56>;
atmel,smc-nrd-pulse-ns = <56>;
atmel,smc-ncs-wr-pulse-ns = <56>;
atmel,smc-nwe-pulse-ns = <56>;
atmel,smc-nwe-cycle-ns = <77>;
atmel,smc-nrd-cycle-ns = <77>;
atmel,smc-tdf-ns = <0>;
};
As you can see, quite a lot of settings are made, all depending on how the
memory access is supposed to be configured. You should look out for details in
the hardware manuals of the SoC and the devices you want to connect.
HTH & Greets
Alex
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: sama5d: using the ebi interface from another driver
2018-11-06 9:57 ` Alexander Dahl
@ 2018-11-07 17:07 ` Jean-Michel Hautbois
0 siblings, 0 replies; 4+ messages in thread
From: Jean-Michel Hautbois @ 2018-11-07 17:07 UTC (permalink / raw)
To: ada; +Cc: linux-arm-kernel, boris.brezillon, Nicolas Ferre, linux-kernel
Hi there !
Le mar. 6 nov. 2018 à 10:57, Alexander Dahl <ada@thorsis.com> a écrit :
>
> Hei hei,
>
> Am Freitag, 2. November 2018, 14:35:26 CET schrieb Jean-Michel Hautbois:
> > Then, after looking into deeper details in the datasheet I understand
> > it is connected through EBI and it sounds not so easy :D.
>
> Did you read docs on that? You'll find the binding docs here:
>
> Documentation/devicetree/bindings/memory-controllers/atmel,ebi.txt
>
> > I would appreciate some help/pointers on this, as there is (at least,
> > I could find) few documentation on how to use it except for NAND
> > cases.
>
> I use EBI with at91sam9g20 and custom FPGA on CS5 (0x6000000) and CS7
> (0x8000000).
>
> > I have something like that in my DTS, but not sure this is the correct
> > way to do it :
> >
> > ebi: ebi@10000000 {
> > pinctrl-0 = <&pinctrl_ebi_nand_addr>;
> > pinctrl-names = "default";
> > status = "okay";
> >
> > dsp0: pef24628@1 {
> > status = "okay";
> > compatible = "intel,pef24628";
> > #address-cells = <1>;
> > #size-cells = <1>;
> > reg = <0x1 0x0 0x8000>;
> > pinctrl-0 = <&pinctrl_dsp_cs1>;
> > };
> >
> > dsp1: pef24628@2 {
> > status = "okay";
> > compatible = "intel,pef24628";
> > #address-cells = <1>;
> > #size-cells = <1>;
> > reg = <0x2 0x0 0x8000>;
> > pinctrl-0 = <&pinctrl_dsp_cs2>;
> > };
>
> I'm not sure about those 'reg' settings. IIRC the first should correspond to
> the CS line, on at91sam9g20 the 0x40000000 would be CS3 (which is used by
> NAND, like in the dts snippet you posted) and 0x50000000 would be CS4. Are CS1
> (which is used by SD-RAM) and CS2 free to use on sama5d3?
>
> Maybe that's different on sama5d3? I would check it again.
Well, yes, I am using CS1 and 2, and right now, I can confirm the reg
settings are ok as the platform_get_resource returns the correct
values :) !
> > The pinctrl for ebi should probably be changed however, I am wondering
> > how the (platform ?) driver can access the adress ? Should it parse
> > itself the parent, and find range, etc. Or is there an accessor for it
> > ?
>
> Probably. This is what I have for the at91sam9g20:
>
> pinctrl@fffff400 {
> ebi {
> pinctrl_ebi_cs5: ebi-cs5-0 {
> atmel,pins =
> <AT91_PIOC 9 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;
> };
>
> pinctrl_ebi_cs7: ebi-cs7-0 {
> atmel,pins =
> <AT91_PIOC 12 AT91_PERIPH_B AT91_PINCTRL_PULL_UP>;
> };
>
> pinctrl_ebi_nwait: ebi-nwait-0 {
> atmel,pins =
> <AT91_PIOC 15 AT91_PERIPH_A AT91_PINCTRL_PULL_UP>;
> };
> };
> };
>
> > Maybe can I just manually toggle the CS GPIO, and don't try to make
> > anything more complex than what it should be ? The driver should not
> > be atmel dependant...
>
> As Ludovic said, you should check the settings and timings for the external
> memory interface. This could look more or less similar to that:
>
> foo_bar: foo-bar@5,0 {
> status = "okay";
> pinctrl-0 = <&pinctrl_ebi_cs5>;
> pinctrl-names = "default";
> reg = <0x5 0x0 0x80000>;
>
> atmel,smc-bus-width = <8>;
> atmel,smc-read-mode = "nrd";
> atmel,smc-write-mode = "nwe";
> atmel,smc-exnw-mode = "ready";
>
> atmel,smc-ncs-rd-setup-ns = <7>;
> atmel,smc-nrd-setup-ns = <7>;
> atmel,smc-ncs-wr-setup-ns = <7>;
> atmel,smc-nwe-setup-ns = <7>;
>
> atmel,smc-ncs-rd-pulse-ns = <56>;
> atmel,smc-nrd-pulse-ns = <56>;
> atmel,smc-ncs-wr-pulse-ns = <56>;
> atmel,smc-nwe-pulse-ns = <56>;
>
> atmel,smc-nwe-cycle-ns = <77>;
> atmel,smc-nrd-cycle-ns = <77>;
>
> atmel,smc-tdf-ns = <0>;
> };
>
> As you can see, quite a lot of settings are made, all depending on how the
> memory access is supposed to be configured. You should look out for details in
> the hardware manuals of the SoC and the devices you want to connect.
Yes, this is the last part I need to get information about, but this
is datasheet reading basically, so not a big deal :).
Thanks to both of you, Alexander and Ludovic, I have now something
really better ;).
JM
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-11-02 13:35 sama5d: using the ebi interface from another driver Jean-Michel Hautbois
2018-11-05 9:19 ` Ludovic Desroches
2018-11-06 9:57 ` Alexander Dahl
2018-11-07 17:07 ` Jean-Michel Hautbois
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