Re: [PATCH v2 05/11] memory: add Atmel EBI (External Bus Interface) driver

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Wed, 5 Nov 2014 17:53:42 +0100
Jean-Jacques Hiblot <jjhiblot@traphandler.com> wrote:

> 2014-11-05 17:01 GMT+01:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
> > The EBI (External Bus Interface) is used to access external peripherals
> > (NOR, SRAM, NAND, and other specific devices like ethernet controllers).
> > Each device is assigned a CS line and an address range and can have its
> > own configuration (timings, access mode, bus width, ...).
> > This driver provides a generic DT binding to configure a device according
> > to its requirements.
> > For specific device controllers (like the NAND one) the SMC timings
> > should be configured by the controller driver through the matrix and
> > smc syscon regmaps.
> >
> > Signed-off-by: Jean-Jacques Hiblot <jjhiblot@traphandler.com>
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> >  drivers/memory/Kconfig     |  11 +
> >  drivers/memory/Makefile    |   1 +
> >  drivers/memory/atmel-ebi.c | 615 +++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 627 insertions(+)
> >  create mode 100644 drivers/memory/atmel-ebi.c
> >
> > diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> > index 6d91c27..dfe24a2 100644
> > --- a/drivers/memory/Kconfig
> > +++ b/drivers/memory/Kconfig
> > @@ -17,6 +17,17 @@ config ATMEL_SDRAMC
> >           Starting with the at91sam9g45, this controller supports SDR, DDR and
> >           LP-DDR memories.
> >
> > +config ATMEL_EBI
> > +       bool "Atmel EBI driver"
> > +       default y
> > +       depends on ARCH_AT91 && OF
> > +       select MFD_SYSCON
> > +       help
> > +         Driver for Atmel EBI controller.
> > +         Used to configure the EBI (external bus interface) when the device-
> > +         tree is used. This bus supports NANDs, external ethernet controller,
> > +         SRAMs, ATA devices, etc.
> > +
> >  config TI_AEMIF
> >         tristate "Texas Instruments AEMIF driver"
> >         depends on (ARCH_DAVINCI || ARCH_KEYSTONE) && OF
> > diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> > index c32d319..7ca2c19 100644
> > --- a/drivers/memory/Makefile
> > +++ b/drivers/memory/Makefile
> > @@ -6,6 +6,7 @@ ifeq ($(CONFIG_DDR),y)
> >  obj-$(CONFIG_OF)               += of_memory.o
> >  endif
> >  obj-$(CONFIG_ATMEL_SDRAMC)     += atmel-sdramc.o
> > +obj-$(CONFIG_ATMEL_EBI)                += atmel-ebi.o
> >  obj-$(CONFIG_TI_AEMIF)         += ti-aemif.o
> >  obj-$(CONFIG_TI_EMIF)          += emif.o
> >  obj-$(CONFIG_FSL_CORENET_CF)   += fsl-corenet-cf.o
> > diff --git a/drivers/memory/atmel-ebi.c b/drivers/memory/atmel-ebi.c
> > new file mode 100644
> > index 0000000..41bc893
> > --- /dev/null
> > +++ b/drivers/memory/atmel-ebi.c
> > @@ -0,0 +1,615 @@
> > +/*
> > + * EBI driver for Atmel SAM9 chips
> > + * inspired by the fsl weim bus driver
> > + *
> > + * Copyright (C) 2013 JJ Hiblot.
> > + *
> > + * This file is licensed under the terms of the GNU General Public
> > + * License version 2. This program is licensed "as is" without any
> > + * warranty of any kind, whether express or implied.
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/io.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/mfd/syscon/atmel-matrix.h>
> > +#include <linux/mfd/syscon/atmel-smc.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/regmap.h>
> > +
> > +#define AT91SAM9_SMC_READ_MODE_MSK     BIT(0)
> > +#define AT91SAM9_SMC_READ_NCS_MODE     0
> > +#define AT91SAM9_SMC_READ_NRD_MODE     1
> > +#define AT91SAM9_SMC_WRITE_MODE_MSK    BIT(1)
> > +#define AT91SAM9_SMC_WRITE_NCS_MODE    (0 << 1)
> > +#define AT91SAM9_SMC_WRITE_NWE_MODE    (1 << 1)
> > +#define AT91SAM9_SMC_EXNW_MODE_MSK     GENMASK(5, 4)
> > +#define AT91SAM9_SMC_EXNW_DIS          (0 << 4)
> > +#define AT91SAM9_SMC_EXNW_FROZEN       (2 << 4)
> > +#define AT91SAM9_SMC_EXNW_READY                (3 << 4)
> > +#define AT91SAM9_SMC_BAT_MSK           BIT(8)
> > +#define AT91SAM9_SMC_BAT_SELECT                (0 << 8)
> > +#define AT91SAM9_SMC_BAT_WRITE         (1 << 8)
> > +#define AT91SAM9_SMC_DBW_MSK           GENMASK(13, 12)
> > +#define AT91SAM9_SMC_DBW(x)            ((((x) / 16) & 0x3) << 12)
> > +#define AT91SAM9_SMC_TDF_CYCLES_MSK    GENMASK(19, 16)
> > +#define AT91SAM9_SMC_TDF_CYCLES(x)     (((x) & 0xf) << 16)
> > +#define AT91SAM9_SMC_TDF_MODE_MSK      BIT(20)
> > +#define AT91SAM9_SMC_TDF_OPTIMIZED     (1 << 20)
> > +#define AT91SAM9_SMC_PMEN              BIT(24)
> > +#define AT91SAM9_SMC_PS(x)             ((((x) / 4) & 0x3) << 28)
> 
> Those definitions are now also available in
> linux/mfd/syscon/atmel-smc.h.For consistency sake, this driver should
> probably use the new ones.

That was my intention, I just forgot to cleanup this part...

> BTW this patch should probably be applied after patch 3 "mfd: syscon:
> Add atmel-smc registers definition" and patch 1 "mfd: syscon: Add
> atmel-matrix registers definition"
> 

And it is: patch 05/11 :-)

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com