From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy Paltsev Subject: DW MMC multislot support Date: Fri, 30 Mar 2018 15:37:39 +0000 Message-ID: <1522424259.32101.7.camel@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Language: en-US Content-ID: <1CC2C62C4259CA4791F613D157505327@internal.synopsys.com> Sender: linux-kernel-owner@vger.kernel.org To: "linux-mmc@vger.kernel.org" Cc: "ulf.hansson@linaro.org" , "linux-kernel@vger.kernel.org" , "jh80.chung@samsung.com" , "shawn.lin@rock-chips.com" , "Vineet.Gupta1@synopsys.com" , "Alexey.Brodkin@synopsys.com" , "linux-snps-arc@lists.infradead.org" List-Id: linux-mmc@vger.kernel.org SGksDQoNCkkgaGF2ZSBwbGFucyB0byBhZGQgbXVsdGlzbG90IHN1cHBvcnQgdG8gRGVzaWduV2Fy ZSBNTUMgZHJpdmVyLg0KDQpBcyBvZiB0b2RheSBJIGhhdmUgcHJvb2Ygb2YgY29uY2VwdCBmb3Ig bXVsdGlzbG90IERXIE1NQyBkcml2ZXIgd2l0aCB0d28gc2xvdHMgd29ya2luZw0Kc2ltdWx0YW5l b3VzbHk6DQpJIHJldmVydGVkIGFsbCBjb21taXRzIHdoaWNoIHJlbW92ZSBwcmV2aW91cyBpbXBs ZW1lbnRhdGlvbiBvZiAicHNldWRvLW11bHRpc2xvdCINCmFuZCBhZGQgYWxsIHJlcXVpcmVkIHN0 ZXBzIGZvciBjaGFuZ2luZyBzbG90IG51bWJlciB0byBfX2R3X21jaV9zdGFydF9yZXF1ZXN0IGZ1 bmN0aW9uLg0KDQpCdXQgSSBoYXZlIHNldmVyYWwgaXNzdWVzIHdpdGggc2V0X2lvcyBmdW5jdGlv biBpbiBtdWx0aXNsb3QgbW9kZSAoYXMgZWFjaCBzbG90DQppcyByZWdpc3RlcmVkIGFzIHNlcGFy YXRlIG1tYyBob3N0KToNCjEpIFdlIGNhbiBjaGFuZ2UgY2xvY2sgZm9yIHNsb3QgMSB3aGlsZSBz bG90IDAgaXMgYWN0aXZlLg0KMikgV2UgY2FuIGRpc2FibGUgb25lIHNsb3QgKGJ5IGNhbGxpbmcg c2V0X2lvcyB3aXRoICdwb3dlcl9tb2RlJyA9PSBNTUNfUE9XRVJfT0ZGKQ0KIHdoaWNoIGNhdXNl IGNsb2NrIGRpc2FibGUgZm9yIGFsbCBzbG90cy4NCjMpIFdlIGNhbiBlbmFibGUgb25lIHNsb3Qg KGJ5IGNhbGxpbmcgc2V0X2lvcyB3aXRoICdwb3dlcl9tb2RlJyA9PSBNTUNfUE9XRVJfT04pDQog d2hpY2ggY2F1c2UgRE1BIGFuZCBGSUZPIHJlc2V0IHdoaWxlIGFub3RoZXIgc2xvdCBpcyBhY3Rp dmUuDQpBbmQgc28gb24uLi4NCg0KDQpIZXJlIGlzIG15IGlkZWFzIGhvdyB0byBmaXggdGhpczoN CjEpIEluIHNldF9pb3MgZnVuY3Rpb24gd2UgY2FuIHNpbXBseSBzdG9yZSBwYXJhbWV0ZXJzDQog KGxpa2UgY2xvY2sgc3BlZWQvdGltaW5ncy9idXMgd2lkdGgpIHRvIGNvcnJlc3BvbmRpbmcgc2xv dCBzdHJ1Y3R1cmUgYW5kIGFwcGx5DQogdGhlbSBvbmx5IGluIHRoZSBiZWdpbm5pbmcgb2YgX19k d19tY2lfc3RhcnRfcmVxdWVzdCBmdW5jdGlvbiBpZiBjdXJyZW50IHNsb3QgaXMNCiBjaGFuZ2Vk Lg0KIEFub3RoZXIgb3B0aW9uIGlzIHRvIGNob29zZSBtYXhpbXVtIGNsb2NrIHdoaWNoIGlzIHN1 aXRhYmxlIGZvciBib3RoIHNsb3RzDQogaW5zdGVhZCBvZiBjbG9jayBzd2l0Y2ggb24gZXZlcnkg c2xvdCBjaGFuZ2UuDQoyKSBEbyBhbGwgYWN0aW9ucyBmb3Igc2xvdCBkaXNhYmxpbmcgKCdwb3dl cl9tb2RlJyA9PSBNTUNfUE9XRVJfT0ZGKSBvbmx5IGlmDQogb3RoZXJzIHNsb3RzIGFyZSBkaXNh YmxlZCB0b28uDQozKSBEbyBhbGwgYWN0aW9ucyBmb3Igc2xvdCBlbmFibGluZyAoJ3Bvd2VyX21v ZGUnID09IE1NQ19QT1dFUl9PTikgb25seSBpZg0KIG5vIHNsb3RzIGFyZSBlbmFibGVkLg0KDQoN Ck1heWJlIHlvdSBoYXZlIGFueSBjb21tZW50cyBvciByZW1hcmtzIGFib3V0IHRoaXM/DQpBbGwg Y29tbWVudHMgYW5kIHN1Z2dlc3Rpb25zIGFyZSBtb3JlIHRoYW4gd2VsY29tZS4NCi0tIA0KIEV1 Z2VuaXkgUGFsdHNldg== From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eugeniy.Paltsev@synopsys.com (Eugeniy Paltsev) Date: Fri, 30 Mar 2018 15:37:39 +0000 Subject: DW MMC multislot support List-ID: Message-ID: <1522424259.32101.7.camel@synopsys.com> To: linux-snps-arc@lists.infradead.org Hi, I have plans to add multislot support to DesignWare MMC driver. As of today I have proof of concept for multislot DW MMC driver with two slots working simultaneously: I reverted all commits which remove previous implementation of "pseudo-multislot" and add all required steps for changing slot number to __dw_mci_start_request function. But I have several issues with set_ios function in multislot mode (as each slot is registered as separate mmc host): 1) We can change clock for slot 1 while slot 0 is active. 2) We can disable one slot (by calling set_ios with 'power_mode' == MMC_POWER_OFF) which cause clock disable for all slots. 3) We can enable one slot (by calling set_ios with 'power_mode' == MMC_POWER_ON) which cause DMA and FIFO reset while another slot is active. And so on... Here is my ideas how to fix this: 1) In set_ios function we can simply store parameters (like clock speed/timings/bus width) to corresponding slot structure and apply them only in the beginning of __dw_mci_start_request function if current slot is changed. Another option is to choose maximum clock which is suitable for both slots instead of clock switch on every slot change. 2) Do all actions for slot disabling ('power_mode' == MMC_POWER_OFF) only if others slots are disabled too. 3) Do all actions for slot enabling ('power_mode' == MMC_POWER_ON) only if no slots are enabled. Maybe you have any comments or remarks about this? All comments and suggestions are more than welcome. -- Eugeniy Paltsev