From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roger Quadros Subject: Re: [PATCH 2/2] memory: omap-gpmc: expand the description of the debug facility Date: Wed, 7 Oct 2015 10:45:50 +0300 Message-ID: <5614CDAE.6070604@ti.com> References: <1444162070-22034-1-git-send-email-u.kleine-koenig@pengutronix.de> <1444162070-22034-2-git-send-email-u.kleine-koenig@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <1444162070-22034-2-git-send-email-u.kleine-koenig@pengutronix.de> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= , Tony Lindgren Cc: linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kernel@pengutronix.de List-Id: linux-omap@vger.kernel.org T24gMDYvMTAvMTUgMjM6MDcsIFV3ZSBLbGVpbmUtS8O2bmlnIHdyb3RlOgo+IE1vc3QgcmVnaXN0 ZXIgdmFsdWVzIGZvciB0aGUgY2hpcCBzZWxlY3Qgc2V0dXAgZGVwZW5kIG9uIHRoZSBmcmVxdWVu Y3kKPiBvZiB0aGUgZmNrIGNsb2NrLgo+IFNvIGFkZCBhIGhpbnQgdGhhdCB0aGUgdmFsdWVzIHNl dHVwIGJ5IHRoZSBib290bG9hZGVyIG1pZ2h0IGRpZmZlciBmcm9tCj4gdGhlIHJpZ2h0IHNldHVw IGZvciBMaW51eCBpZiB0aGUgYm9vdGxvYWRlciB1c2VzIGEgZGlmZmVyZW50IGZyZXF1ZW5jeS4K PiAKPiBTaWduZWQtb2ZmLWJ5OiBVd2UgS2xlaW5lLUvDtm5pZyA8dS5rbGVpbmUta29lbmlnQHBl bmd1dHJvbml4LmRlPgo+IC0tLQo+ICBkcml2ZXJzL21lbW9yeS9LY29uZmlnIHwgMyArKysKPiAg MSBmaWxlIGNoYW5nZWQsIDMgaW5zZXJ0aW9ucygrKQo+IAo+IGRpZmYgLS1naXQgYS9kcml2ZXJz L21lbW9yeS9LY29uZmlnIGIvZHJpdmVycy9tZW1vcnkvS2NvbmZpZwo+IGluZGV4IGM2YTY0NGIy MmFmNC4uMTQxNGRkNTNiZTU3IDEwMDY0NAo+IC0tLSBhL2RyaXZlcnMvbWVtb3J5L0tjb25maWcK PiArKysgYi9kcml2ZXJzL21lbW9yeS9LY29uZmlnCj4gQEAgLTY0LDYgKzY0LDkgQEAgY29uZmln IE9NQVBfR1BNQ19ERUJVRwo+ICAJICBFbmFibGVzIHZlcmJvc2UgZGVidWdnaW5nIG1vc3RseSB0 byBkZWNvZGUgdGhlIGJvb3Rsb2FkZXIgcHJvdmlkZWQKPiAgCSAgdGltaW5ncy4gRW5hYmxlIHRo aXMgZHVyaW5nIGRldmVsb3BtZW50IHRvIGNvbmZpZ3VyZSBkZXZpY2VzCj4gIAkgIGNvbm5lY3Rl ZCB0byB0aGUgR1BNQyBidXMuCj4gKwkgIE5vdGUgdGhhdCB5b3UgY2Fubm90IGp1c3QgdHdlYWsg eW91ciBkZXZpY2UgdHJlZSB1bnRpbCB0aGUgcmVnaXN0ZXJzCj4gKwkgIHNldHVwIGJ5IGxpbnV4 IG1hdGNoIHdoYXQgdGhlIGJvb3Rsb2FkZXIgZGlkIGJlY2F1c2UgdGhhdCBvbmUgbWlnaHQKPiAr CSAgdXNlIGEgZGlmZmVyZW50IGZjayBmcmVxdWVuY3kgaW5mbHVlbmNpbmcgbW9zdCByZWdpc3Rl ciBzZXR0aW5ncy4KCkxvb2tzIGxpa2Ugd2UgY2FuJ3Qga25vdyBmb3Igc3VyZSB0aGUgR1BNQyBm Y2xrIHVzZWQgYXQgdGhlIGJvb3Rsb2FkZXIKZWxzZSB3ZSBjb3VsZCBoYXZlIGp1c3QgcHJpbnRl ZCB0aGUgR1BNQyBmY2xrIHByZSBhbmQgcG9zdCBncG1jIHNldHRpbmdzLgoKSG93IGFib3V0IHRo aXMgaW5zdGVhZD8KCk5PVEU6IEFwYXJ0IGZyb20gbWF0Y2hpbmcgdGhlIHJlZ2lzdGVyIHNldHVw IHdpdGggdGhlIGJvb3Rsb2FkZXIgeW91IGFsc28gbmVlZCB0bwptYXRjaCB0aGUgR1BNQyBGQ0xL IGZyZXF1ZW5jeSB1c2VkIGJ5IHRoZSBib290bG9hZGVyIGVsc2UgdGhlIEdQTUMgdGltaW5ncwp3 b24ndCBiZSBpZGVudGljYWwgd2l0aCB0aGUgYm9vdGxvYWRlciB0aW1pbmdzLgoKQWxzbyB5b3Ug bWlnaHQgbmVlZCB0byBidWlsZCB0aGlzIHBhdGNoIG9uIHRvcCBvZgpodHRwOi8vYXJ0aWNsZS5n bWFuZS5vcmcvZ21hbmUubGludXgua2VybmVsLzIwNTQ3OTYKCj4gIAo+ICBjb25maWcgTVZFQlVf REVWQlVTCj4gIAlib29sICJNYXJ2ZWxsIEVCVSBEZXZpY2UgQnVzIENvbnRyb2xsZXIiCj4gCgpj aGVlcnMsCi1yb2dlcgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBsaXN0 cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlzdGlu Zm8vbGludXgtYXJtLWtlcm5lbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 From: rogerq@ti.com (Roger Quadros) Date: Wed, 7 Oct 2015 10:45:50 +0300 Subject: [PATCH 2/2] memory: omap-gpmc: expand the description of the debug facility In-Reply-To: <1444162070-22034-2-git-send-email-u.kleine-koenig@pengutronix.de> References: <1444162070-22034-1-git-send-email-u.kleine-koenig@pengutronix.de> <1444162070-22034-2-git-send-email-u.kleine-koenig@pengutronix.de> Message-ID: <5614CDAE.6070604@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 06/10/15 23:07, Uwe Kleine-K?nig wrote: > Most register values for the chip select setup depend on the frequency > of the fck clock. > So add a hint that the values setup by the bootloader might differ from > the right setup for Linux if the bootloader uses a different frequency. > > Signed-off-by: Uwe Kleine-K?nig > --- > drivers/memory/Kconfig | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig > index c6a644b22af4..1414dd53be57 100644 > --- a/drivers/memory/Kconfig > +++ b/drivers/memory/Kconfig > @@ -64,6 +64,9 @@ config OMAP_GPMC_DEBUG > Enables verbose debugging mostly to decode the bootloader provided > timings. Enable this during development to configure devices > connected to the GPMC bus. > + Note that you cannot just tweak your device tree until the registers > + setup by linux match what the bootloader did because that one might > + use a different fck frequency influencing most register settings. Looks like we can't know for sure the GPMC fclk used at the bootloader else we could have just printed the GPMC fclk pre and post gpmc settings. How about this instead? NOTE: Apart from matching the register setup with the bootloader you also need to match the GPMC FCLK frequency used by the bootloader else the GPMC timings won't be identical with the bootloader timings. Also you might need to build this patch on top of http://article.gmane.org/gmane.linux.kernel/2054796 > > config MVEBU_DEVBUS > bool "Marvell EBU Device Bus Controller" > cheers, -roger