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SubjectRe: [RFC PATCH 4/8] misc: emif: add basic infrastructure for EMIF driver
On Saturday 04 February 2012 05:46 PM, Aneesh V wrote:
> EMIF is an SDRAM controller used in various Texas Instruments
> SoCs. EMIF supports, based on its revision, one or more of
> LPDDR2/DDR2/DDR3 protocols.
>
> Add the basic infrastructure for EMIF driver that includes
> driver registration, probe, parsing of platform data etc.
>
> Signed-off-by: Aneesh V <aneesh@ti.com>
> ---
> drivers/misc/Kconfig | 12 ++
> drivers/misc/Makefile | 1 +
> drivers/misc/emif.c | 300 +++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/emif.h | 160 ++++++++++++++++++++++++++
> 4 files changed, 473 insertions(+), 0 deletions(-)
> create mode 100644 drivers/misc/emif.c
> create mode 100644 include/linux/emif.h
>
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 8337bf6..d68184a 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -459,6 +459,18 @@ config DDR
> information. This data is useful for drivers handling
> DDR SDRAM controllers.
>
> +config EMIF

Add TI prefix here since it's TI IP and not a generic one.

> + tristate "Texas Instruments EMIF driver"
> + select DDR
> + help
> + This driver is for the EMIF module available in Texas Instruments
> + SoCs. EMIF is an SDRAM controller that, based on its revision,
> + supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols.
> + This driver takes care of only LPDDR2 memories presently. The
> + functions of the driver includes re-configuring AC timing
> + parameters and other settings during frequency, voltage and
> + temperature changes
> +
> config ARM_CHARLCD
> bool "ARM Ltd. Character LCD Driver"
> depends on PLAT_VERSATILE
> diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
> index 4759166..076db0f 100644
> --- a/drivers/misc/Makefile
> +++ b/drivers/misc/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_C2PORT) += c2port/
> obj-$(CONFIG_IWMC3200TOP) += iwmc3200top/
> obj-$(CONFIG_HMC6352) += hmc6352.o
> obj-$(CONFIG_DDR) += jedec_ddr_data.o
> +obj-$(CONFIG_EMIF) += emif.o
> obj-y += eeprom/
> obj-y += cb710/
> obj-$(CONFIG_SPEAR13XX_PCIE_GADGET) += spear13xx_pcie_gadget.o
> diff --git a/drivers/misc/emif.c b/drivers/misc/emif.c
> new file mode 100644
> index 0000000..ba1e3f9
> --- /dev/null
> +++ b/drivers/misc/emif.c
> @@ -0,0 +1,300 @@
> +/*
> + * EMIF driver
> + *
> + * Copyright (C) 2010 Texas Instruments, Inc.
Fix year. 2012
> + *
> + * Aneesh V <aneesh@ti.com>
> + * Santosh Shilimkar <santosh.shilimkar@ti.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include <linux/kernel.h>
> +#include <linux/reboot.h>
> +#include <linux/emif.h>
> +#include <linux/io.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/slab.h>
> +#include <linux/seq_file.h>
> +#include <linux/module.h>
> +#include <linux/spinlock.h>
> +#include "emif_regs.h"
> +
> +/**
> + * struct emif_data - Per device static data for driver's use
> + * @duplicate: Whether the DDR devices attached to this EMIF
> + * instance are exactly same as that on EMIF1. In
> + * this case we can save some memory and processing
> + * @temperature_level: Maximum temperature of LPDDR2 devices attached
> + * to this EMIF - read from MR4 register. If there
> + * are two devices attached to this EMIF, this
> + * value is the maximum of the two temperature
> + * levels.
> + * @irq: IRQ number
> + * @lock: lock for protecting temperature_level and
> + * associated actions from race conditions
> + * @base: base address of memory-mapped IO registers.
> + * @dev: device pointer.
> + * @addressing table with addressing information from the spec
> + * @regs_cache: An array of 'struct emif_regs' that stores
> + * calculated register values for different
> + * frequencies, to avoid re-calculating them on
> + * each DVFS transition.
> + * @curr_regs: The set of register values used in the last
> + * frequency change (i.e. corresponding to the
> + * frequency in effect at the moment)
> + * @plat_data: Pointer to saved platform data.
> + */
> +struct emif_data {
> + u8 duplicate;
> + u8 temperature_level;
> + u32 irq;
> + spinlock_t lock; /* lock to prevent races */
> + void __iomem *base;
> + struct device *dev;
> + const struct lpddr2_addressing *addressing;
> + struct emif_regs *regs_cache[EMIF_MAX_NUM_FREQUENCIES];
> + struct emif_regs *curr_regs;
> + struct emif_platform_data *plat_data;
> +};
> +
> +static struct emif_data *emif1;
> +
> +static void __exit cleanup_emif(struct emif_data *emif)
> +{
> + if (emif) {
> + if (emif->plat_data) {
> + kfree(emif->plat_data->custom_configs);
> + kfree(emif->plat_data->timings);
> + kfree(emif->plat_data->min_tck);
> + kfree(emif->plat_data->device_info);
> + kfree(emif->plat_data);
> + }
> + kfree(emif);
> + }
> +}
> +
You might want to consider use of devm_kzalloc() kind of
API so that you can get rid of above free stuff.

> +static void get_default_timings(struct emif_data *emif)
> +{
> + struct emif_platform_data *pd = emif->plat_data;
> +
> + pd->timings = lpddr2_jedec_timings;
> + pd->timings_arr_size = ARRAY_SIZE(lpddr2_jedec_timings);
> +
> + dev_warn(emif->dev, "Using default timings\n");
> +}
Would be good if you add __line__ in all the errors and
warnings. Helps to trace messages faster.

> +
> +static int is_dev_data_valid(u32 type, u32 density, u32 io_width, u32 phy_type,
> + u32 ip_rev, struct device *dev)
> +{
> + int valid;
> +
> + valid = (type == DDR_TYPE_LPDDR2_S4 ||
> + type == DDR_TYPE_LPDDR2_S2)
> + && (density >= DDR_DENSITY_64Mb
> + && density <= DDR_DENSITY_8Gb)
> + && (io_width >= DDR_IO_WIDTH_8
> + && io_width <= DDR_IO_WIDTH_32);
> +
> + /* Combinations of EMIF and PHY revisions that we support today */
> + switch (ip_rev) {
> + case EMIF_4D:
> + valid = valid && (phy_type == EMIF_PHY_TYPE_ATTILAPHY);
> + break;
> + case EMIF_4D5:
> + valid = valid && (phy_type == EMIF_PHY_TYPE_INTELLIPHY);
> + break;
> + default:
> + valid = 0;
> + }
> +
> + if (!valid)
> + dev_err(dev, "Invalid DDR details\n");
> + return valid;
Generally return 0 means success. you might want to consider
returning -EINVAL or similar.

> +}
> +
> +static int is_custom_config_valid(struct emif_custom_configs *cust_cfgs,
> + struct device *dev)
> +{
> + int valid = 1;
> +
> + if ((cust_cfgs->mask & EMIF_CUSTOM_CONFIG_LPMODE) &&
> + (cust_cfgs->lpmode != EMIF_LP_MODE_DISABLE))
> + valid = cust_cfgs->lpmode_freq_threshold &&
> + cust_cfgs->lpmode_timeout_performance &&
> + cust_cfgs->lpmode_timeout_power;
> +
> + if (cust_cfgs->mask & EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL)
> + valid = valid && cust_cfgs->temp_alert_poll_interval_ms;
> +
> + if (!valid)
> + dev_warn(dev, "Invalid custom configs\n");
> +
> + return valid;
> +}
> +
Ditto

> +static struct emif_data * __init get_device_details(
> + struct platform_device *pdev)
> +{
> + u32 size;
> + struct emif_data *emif = NULL;
> + struct ddr_device_info *dev_info;
> + struct emif_platform_data *pd;
> +
> + pd = pdev->dev.platform_data;
> +
extra line
> + if (!(pd && pd->device_info && is_dev_data_valid(pd->device_info->type,
> + pd->device_info->density, pd->device_info->io_width,
> + pd->phy_type, pd->ip_rev, &pdev->dev)))
> + goto error;
> +
> + emif = kzalloc(sizeof(struct emif_data), GFP_KERNEL);
> + pd = kmemdup(pd, sizeof(*pd), GFP_KERNEL);
> + dev_info = kmemdup(pd->device_info,
> + sizeof(*pd->device_info), GFP_KERNEL);
> +
here too
> + if (!emif || !pd || !dev_info)
> + goto error;
> +
> + emif->plat_data = pd;
> + emif->dev = &pdev->dev;
> + emif->temperature_level = SDRAM_TEMP_NOMINAL;
> +
and here
> + pd->device_info = dev_info;
> +
> + /*
> + * For EMIF instances other than EMIF1 see if the devices connected
> + * are exactly same as on EMIF1(which is typically the case). If so,
> + * mark it as a duplicate of EMIF1 and skip copying timings data.
> + * This will save some memory and some computation later.
> + */
> + emif->duplicate = emif1 && (memcmp(dev_info,
> + emif1->plat_data->device_info,
> + sizeof(struct ddr_device_info)) == 0);
> +
and here
> + if (emif->duplicate) {
> + pd->timings = NULL;
> + pd->min_tck = NULL;
> + goto out;
> + }
> +
> + /*
> + * Copy custom configs - ignore allocation error, if any, as
> + * custom_configs is not very critical
> + */
> + if (pd->custom_configs)
> + pd->custom_configs = kmemdup(pd->custom_configs,
> + sizeof(*pd->custom_configs), GFP_KERNEL);
> +
> + if (pd->custom_configs &&
> + !is_custom_config_valid(pd->custom_configs, emif->dev)) {
> + kfree(pd->custom_configs);
> + pd->custom_configs = NULL;
> + }
> +
> + /*
> + * Copy timings and min-tck values from platform data. If it is not
> + * available or if memory allocation fails, use JEDEC defaults
> + */
> + size = sizeof(struct lpddr2_timings) * pd->timings_arr_size;
> + if (pd->timings)
> + pd->timings = kmemdup(pd->timings, size, GFP_KERNEL);
> +
> + if (!pd->timings)
> + get_default_timings(emif);
> +
> + if (pd->min_tck)
> + pd->min_tck = kmemdup(pd->min_tck, sizeof(*pd->min_tck),
> + GFP_KERNEL);
> +
> + if (!pd->min_tck) {
else on above if should work, right ?

> + pd->min_tck = &lpddr2_min_tck;
> + dev_warn(emif->dev, "Using default min-tck values\n");
> + }
> +
> + goto out;
> +
> +error:
> + dev_err(&pdev->dev, "get_device_details() failure!!\n");
> + cleanup_emif(emif);
> + return NULL;
> +
> +out:
> + return emif;
> +}
> +
> +static int __init emif_probe(struct platform_device *pdev)
> +{
> + struct emif_data *emif;
> + struct resource *res;
> +
> + emif = get_device_details(pdev);
> +
extra line

> + if (!emif)
> + goto error;
> +
> + if (!emif1)
> + emif1 = emif;
> +
> + /* Save pointers to each other in emif and device structures */
> + emif->dev = &pdev->dev;
> + platform_set_drvdata(pdev, emif);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + goto error;
> +
> + emif->base = ioremap(res->start, SZ_1M);
> + if (!emif->base)
> + goto error;
> +
> + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> + if (!res)
> + goto error;
you might want add a line here
> + emif->irq = res->start;
> +
And remove this one
> + dev_info(&pdev->dev, "Device configured with addr = %p and IRQ%d\n",
> + emif->base, emif->irq);
> + return 0;
> +
> +error:
> + dev_err(&pdev->dev, "probe failure!!\n");
> + cleanup_emif(emif);
> + return -ENODEV;
> +}
> +
> +static int __exit emif_remove(struct platform_device *pdev)
> +{
> + struct emif_data *emif = platform_get_drvdata(pdev);
> +
> + cleanup_emif(emif);
> +
> + return 0;
> +}
> +
> +static struct platform_driver emif_driver = {
> + .remove = __exit_p(emif_remove),
> + .driver = {
> + .name = "emif",
> + },
> +};
> +
> +static int __init emif_register(void)
> +{
> + return platform_driver_probe(&emif_driver, emif_probe);
> +}
> +
> +static void __exit emif_unregister(void)
> +{
> + platform_driver_unregister(&emif_driver);
> +}
> +
> +module_init(emif_register);
> +module_exit(emif_unregister);
> +MODULE_DESCRIPTION("TI EMIF SDRAM Controller Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:emif");
> +MODULE_AUTHOR("Texas Instruments Inc");
> diff --git a/include/linux/emif.h b/include/linux/emif.h
> new file mode 100644
> index 0000000..4ddf20b
> --- /dev/null
> +++ b/include/linux/emif.h
> @@ -0,0 +1,160 @@
> +/*
> + * Definitions for EMIF SDRAM controller in TI SoCs
> + *
> + * Copyright (C) 2010 Texas Instruments, Inc.
> + *
2012

> + * Aneesh V <aneesh@ti.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#ifndef __LINUX_EMIF_H
> +#define __LINUX_EMIF_H
> +
> +#ifndef __ASSEMBLY__
> +#include <linux/jedec_ddr.h>
> +
> +/*
> + * Maximum number of different frequencies supported by EMIF driver
> + * Determines the number of entries in the pointer array for register
> + * cache
> + */
> +#define EMIF_MAX_NUM_FREQUENCIES 6
> +
> +/* EMIF_PWR_MGMT_CTRL register */
> +/* Low power modes */
Combine above two line comments in one
comment.

> +#define EMIF_LP_MODE_DISABLE 0
> +#define EMIF_LP_MODE_CLOCK_STOP 1
> +#define EMIF_LP_MODE_SELF_REFRESH 2
> +#define EMIF_LP_MODE_PWR_DN 4
> +
> +/* Hardware capabilities */
> +#define EMIF_HW_CAPS_LL_INTERFACE 0x00000001
> +
> +/* EMIF IP Revisions */
> +#define EMIF_4D 1
> +#define EMIF_4D5 2
> +
> +/* PHY types */
> +#define EMIF_PHY_TYPE_ATTILAPHY 1
> +#define EMIF_PHY_TYPE_INTELLIPHY 2
> +
> +/* Custom config requests */
> +#define EMIF_CUSTOM_CONFIG_LPMODE 0x00000001
> +#define EMIF_CUSTOM_CONFIG_TEMP_ALERT_POLL_INTERVAL 0x00000002
> +

try to aling numbers for all the above defines.

With above minor comments, the patch looks fine to me.

Regards
Santosh


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