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received-spf: None (protection.outlook.com: nxp.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: +SXRN1JvUHZiv/4TbhIL4kCXLKFqGiNYO+pkixZfzQNjbIun3L0CRHQFmBjx1To5K6D65Vv+Qa5yfZvwos7o9qsMvb9Xh97lOdrNdqxDoAUdTYX53+cHa897xxCpSiI1iMtRgXncqhhJPyTdnaQxYWH9rSHjmN4i9GzTQrucHdYjH3PIVUIujGkXVS7nRsVTFFKFEJo2f0njgZ9KVWhKtrrOS9srDkIX376XKgCiZs86esQqV9+R5fpcG6UGZ8BLMYX8qmKM4N7TJm/fJjvLmmM0WkbghdpmaaoQuRh0RwPhp3P3fbojlQ7OAYaVXCmYJMED1pCiArlTnquch+JszYlU0JBQhfcOuNPKdQ+z/MmuFq6isrZDqypy8TFULsCttUbrZ6FLWWA+N+Q9rLhzxp12V9Uddn4mif89yI1m218= Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 2aaeec75-efc9-4238-41ac-08d73afa2544 X-MS-Exchange-CrossTenant-originalarrivaltime: 16 Sep 2019 23:03:53.1505 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 0NYscR2kuTkMAyF6kSDq5MwS/ifrDhvNjz6LQjAv7GxCP/KHIDPpviVHvqwoHtlmIG0fKnI4AF7hGUC2A2F5XA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR04MB5806 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 2019-09-16 11:33 PM, Stephen Boyd wrote:=0A= > Quoting Leonard Crestez (2019-08-20 08:45:06)=0A= >> Dram frequency changes required modifying these clocks outside the=0A= >> control of clk framework. Mark them as CLK_GET_RATE_NOCACHE so that=0A= >> rates are always read back from registers.=0A= > =0A= > Why can't we control the clks from the clk framework? Please add that=0A= > information in the commit text here.=0A= =0A= OK, I will update commit message and comments=0A= =0A= These clocks are only modified for DRAM frequency switches during which =0A= DRAM is briefly inaccessible. The switch is performed with a SMC call to = =0A= by TF-A which runs from a SRAM area. Upon returning to linux several =0A= clocks bits are modified and we need to update them.=0A= =0A= For rate bits an easy solution is to just mark with =0A= CLK_GET_RATE_NOCACHE, muxes are handled explicitly.=0A= =0A= Linux code performing the SMC call is also part of this series:=0A= =0A= https://patchwork.kernel.org/patch/11104145/=0A= =0A= >> Signed-off-by: Leonard Crestez =0A= >> ---=0A= >> drivers/clk/imx/clk-imx8mm.c | 6 ++++--=0A= >> drivers/clk/imx/clk-imx8mn.c | 6 ++++--=0A= >> drivers/clk/imx/clk-imx8mq.c | 7 ++++---=0A= >> 3 files changed, 12 insertions(+), 7 deletions(-)=0A= >>=0A= >> diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c= =0A= >> index 4ead3ea2713c..6cac80550f43 100644=0A= >> --- a/drivers/clk/imx/clk-imx8mm.c=0A= >> +++ b/drivers/clk/imx/clk-imx8mm.c=0A= >> @@ -526,12 +526,14 @@ static int imx8mm_clocks_probe(struct platform_dev= ice *pdev)=0A= >> /* IPG */=0A= >> clks[IMX8MM_CLK_IPG_ROOT] =3D imx_clk_divider2("ipg_root", "ahb= ", base + 0x9080, 0, 1);=0A= >> clks[IMX8MM_CLK_IPG_AUDIO_ROOT] =3D imx_clk_divider2("ipg_audio= _root", "audio_ahb", base + 0x9180, 0, 1);=0A= >> =0A= >> /* IP */=0A= >> - clks[IMX8MM_CLK_DRAM_ALT] =3D imx8m_clk_composite("dram_alt", im= x8mm_dram_alt_sels, base + 0xa000);=0A= >> - clks[IMX8MM_CLK_DRAM_APB] =3D imx8m_clk_composite_critical("dram= _apb", imx8mm_dram_apb_sels, base + 0xa080);=0A= >> + clks[IMX8MM_CLK_DRAM_ALT] =3D __imx8m_clk_composite("dram_alt", = imx8mm_dram_alt_sels, base + 0xa000,=0A= >> + CLK_GET_RATE_NOCACHE);=0A= >> + clks[IMX8MM_CLK_DRAM_APB] =3D __imx8m_clk_composite("dram_apb", = imx8mm_dram_apb_sels, base + 0xa080,=0A= >> + CLK_IS_CRITICAL | CLK_GET_RATE_NOCACHE);=0A= > =0A= > Also, add a comment to this effect about why it can't be done from the=0A= > clk framework wherever the CLK_GET_RATE_NOCACHE flag is set. Basically=0A= > this flag is a hack and is an example of something that we need to fix.= =0A= =0A= DRAM freq switch requires multiple clk changes to be performed =0A= atomically while DRAM itself is not accessible so it's not something to =0A= "fix".=0A= =0A= --=0A= Regards,=0A= Leonard=0A=