Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On Wed 2014-08-27 12:11:55, Jaehoon Chung wrote: Hi, On 08/26/2014 07:19 PM, Pavel Machek wrote: Hi! Would you elaborate? If I have a device like a phone, I may want to put one slot inside phone for basic system, and offer second slot for user expansion (initially empty). if multiple slot is supported, then a mmcqd should be processing for multiple slots. It's too inefficient, and affect the whole performance reduction. Sorry, Discard this comment. it means dwmci, not mmcqd. Well, that's a Linux problem, and for many applications, not even problem at all. Device tree should describe hardware, and hardware can do multiple slots per controller, so device tree should describe multiple slots per controller. Now, the configuration may be uncommon, but you are moving from good hardware description to bad hardware description. Well, i don't think it's bad hardware description. And this policy is suggested by other mmc developers and maintainers. At first time, I had also suggested same opinion with yours. Refer to below.. Well, I disagree with them. They want to modify device tree because of linux limitations. Plus. I guess that sooner or later someone will wire just the slot 1 (not 0) and not match this description. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
Hi! Would you elaborate? If I have a device like a phone, I may want to put one slot inside phone for basic system, and offer second slot for user expansion (initially empty). if multiple slot is supported, then a mmcqd should be processing for multiple slots. It's too inefficient, and affect the whole performance reduction. Sorry, Discard this comment. it means dwmci, not mmcqd. Well, that's a Linux problem, and for many applications, not even problem at all. Device tree should describe hardware, and hardware can do multiple slots per controller, so device tree should describe multiple slots per controller. Now, the configuration may be uncommon, but you are moving from good hardware description to bad hardware description. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
Hi, On 08/26/2014 07:19 PM, Pavel Machek wrote: Hi! Would you elaborate? If I have a device like a phone, I may want to put one slot inside phone for basic system, and offer second slot for user expansion (initially empty). if multiple slot is supported, then a mmcqd should be processing for multiple slots. It's too inefficient, and affect the whole performance reduction. Sorry, Discard this comment. it means dwmci, not mmcqd. Well, that's a Linux problem, and for many applications, not even problem at all. Device tree should describe hardware, and hardware can do multiple slots per controller, so device tree should describe multiple slots per controller. Now, the configuration may be uncommon, but you are moving from good hardware description to bad hardware description. Well, i don't think it's bad hardware description. And this policy is suggested by other mmc developers and maintainers. At first time, I had also suggested same opinion with yours. Refer to below.. https://patchwork.kernel.org/patch/4276481/ Best Regards, Jaehoon Chung Pavel -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On Thu 2014-08-07 16:37:57, Jaehoon Chung wrote: Since used the mmc_of_parse(), didn't parse the sub-node. So we can remove the sub-node, because almost SoC used the only one card per a host. And supports-highspeed can be replaced with cap-mmc/sd-highspeed property. Would it be better to fix parsing of the device tree, and not to change all the device trees? Someone will want to do two slots sooner or later... -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On 08/25/2014 08:21 PM, Pavel Machek wrote: On Thu 2014-08-07 16:37:57, Jaehoon Chung wrote: Since used the mmc_of_parse(), didn't parse the sub-node. So we can remove the sub-node, because almost SoC used the only one card per a host. And supports-highspeed can be replaced with cap-mmc/sd-highspeed property. Would it be better to fix parsing of the device tree, and not to change all the device trees? Someone will want to do two slots sooner or later... First, I had considered that controller can be supported the multiple slot. But MMC maintainers and other people suggested that consider the only one card per a host. Two slots or more don't have any benefit, (power or performance, etc). Best Regards, Jaehoon Chung -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On Mon 2014-08-25 20:28:21, Jaehoon Chung wrote: On 08/25/2014 08:21 PM, Pavel Machek wrote: On Thu 2014-08-07 16:37:57, Jaehoon Chung wrote: Since used the mmc_of_parse(), didn't parse the sub-node. So we can remove the sub-node, because almost SoC used the only one card per a host. And supports-highspeed can be replaced with cap-mmc/sd-highspeed property. Would it be better to fix parsing of the device tree, and not to change all the device trees? Someone will want to do two slots sooner or later... First, I had considered that controller can be supported the multiple slot. But MMC maintainers and other people suggested that consider the only one card per a host. Two slots or more don't have any benefit, (power or performance, etc). Would you elaborate? If I have a device like a phone, I may want to put one slot inside phone for basic system, and offer second slot for user expansion (initially empty). Or I may want to have internal slot with a card to boot from and have external slot (initially empty) for system update for embedded system. I see quite an obvious benefit there. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On 08/25/2014 08:37 PM, Pavel Machek wrote: On Mon 2014-08-25 20:28:21, Jaehoon Chung wrote: On 08/25/2014 08:21 PM, Pavel Machek wrote: On Thu 2014-08-07 16:37:57, Jaehoon Chung wrote: Since used the mmc_of_parse(), didn't parse the sub-node. So we can remove the sub-node, because almost SoC used the only one card per a host. And supports-highspeed can be replaced with cap-mmc/sd-highspeed property. Would it be better to fix parsing of the device tree, and not to change all the device trees? Someone will want to do two slots sooner or later... First, I had considered that controller can be supported the multiple slot. But MMC maintainers and other people suggested that consider the only one card per a host. Two slots or more don't have any benefit, (power or performance, etc). Would you elaborate? If I have a device like a phone, I may want to put one slot inside phone for basic system, and offer second slot for user expansion (initially empty). if multiple slot is supported, then a mmcqd should be processing for multiple slots. It's too inefficient, and affect the whole performance reduction. If want to offer the second slot for user expansion, add the host for expansion slot. Almost All SoC didn't use the multiple slot per a host controller for eMMC/SD/SDIO. If Some device(Phone) supports the SD-card and eMMC, then there are two Host IP. One Host IP is used for eMMC, other is used for SD-card. this is H/W design issue. a) You means the below, One Host IP eMMC | SD | SDIO b) We means the below One Host IP eMMC One Host IP SD One Host IP SDIO In now, I knew every SoC have used like b) type. I didn't see a) type (especially, dwmmc's case). If i missed something, let me know, plz. Best Regards, Jaehoon Chung Or I may want to have internal slot with a card to boot from and have external slot (initially empty) for system update for embedded system. I see quite an obvious benefit there. Pavel -- To unsubscribe from this list: send the line unsubscribe linux-samsung-soc in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCHv10 0/5] ARM: remove the sub-node and deprecate supports-highspeed property for dwmmc.
On 08/25/2014 09:09 PM, Jaehoon Chung wrote:
On 08/25/2014 08:37 PM, Pavel Machek wrote:
On Mon 2014-08-25 20:28:21, Jaehoon Chung wrote:
On 08/25/2014 08:21 PM, Pavel Machek wrote:
On Thu 2014-08-07 16:37:57, Jaehoon Chung wrote:
Since used the mmc_of_parse(), didn't parse the sub-node.
So we can remove the sub-node, because almost SoC used the only one card
per a host.
And supports-highspeed can be replaced with cap-mmc/sd-highspeed
property.
Would it be better to fix parsing of the device tree, and not to
change all the device trees?
Someone will want to do two slots sooner or later...
First, I had considered that controller can be supported the multiple slot.
But MMC maintainers and other people suggested that consider the only one
card per a host.
Two slots or more don't have any benefit, (power or performance, etc).
Would you elaborate?
If I have a device like a phone, I may want to put one slot inside
phone for basic system, and offer second slot for user expansion
(initially empty).
if multiple slot is supported, then a mmcqd should be processing for multiple
slots.
It's too inefficient, and affect the whole performance reduction.
Sorry, Discard this comment. it means dwmci, not mmcqd.
If want to offer the second slot for user expansion, add the host for
expansion slot.
Almost All SoC didn't use the multiple slot per a host controller for
eMMC/SD/SDIO.
If Some device(Phone) supports the SD-card and eMMC, then there are two Host
IP.
One Host IP is used for eMMC, other is used for SD-card.
this is H/W design issue.
a) You means the below,
One Host IP eMMC
|
SD
|
SDIO
b) We means the below
One Host IP eMMC
One Host IP SD
One Host IP SDIO
In now, I knew every SoC have used like b) type. I didn't see a) type
(especially, dwmmc's case).
If i missed something, let me know, plz.
Best Regards,
Jaehoon Chung
Or I may want to have internal slot with a card to boot from and have
external slot (initially empty) for system update for embedded system.
I see quite an obvious benefit there.
Pavel
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