Re: [PATCH v2 00/22] memory: omap-gpmc: mtd: nand: Support GPMC NAND on non-OMAP platforms

From: Tony Lindgren
Date: Tue Aug 11 2015 - 08:48:39 EST

* Roger Quadros <rogerq@xxxxxx> [150807 02:15]:
> Hi,
> We do a couple of things in this series which result in
> cleaner device tree implementation, faster perfomance and
> multi-platform support. As an added bonus we get new GPI/Interrupt pins
> for use in the system.
> - Establish a custom interface between NAND and GPMC driver. This is
> needed because all of the NAND registers sit in the GPMC register space.
> Some bits like NAND IRQ are even shared with GPMC.
> - Remove NAND IRQ handling from omap-gpmc driver, share the GPMC IRQ
> with the omap2-nand driver and handle NAND IRQ events in the NAND driver.
> This causes performance increase when using prefetch-irq mode.
> 30% increase in read, 17% increase in write in prefetch-irq mode.
> - Clean up device tree support so that omap-gpmc IP and the omap2 NAND
> driver can be used on non-OMAP platforms. e.g. Keystone.
> - Implement GPIOCHIP + IRQCHIP for the GPMC WAITPINS. SoCs can contain
> 2 to 4 of these and most of them would be unused otherwise. It also
> allows a cleaner implementation of NAND Ready pin status for the NAND driver.
> - Implement GPIOlib based NAND ready pin checking for OMAP NAND driver.

Nice job :) Using GPIOCHIP + IRQCHIP allows us to make the GPMC
using drivers pretty much generic eventually.

> NOTE: I've only adapted dra7.dtsi and dra7x-evms for this series.
> I will adapt all other boards when the series is in a shape to be accepted.

OK. Yeah let's make sure no regressions are caused by this.. We also
still have the omap3 legacy booting around, have you checked that it
keeps on working?


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