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author | Ezequiel Garcia <ezequiel.garcia@free-electrons.com> | 2013-04-23 21:21:26 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-05-21 19:11:56 +0200 |
commit | 3edad321b1bd2e6c8b5f38146c115c8982438f06 (patch) | |
tree | d58e2393d49e1f1af0797778d1ed87fb6780e8dc /drivers/memory/mvebu-devbus.c | |
parent | uio/uio_cif: Use module_pci_driver to register driver (diff) | |
download | linux-3edad321b1bd2e6c8b5f38146c115c8982438f06.tar.xz linux-3edad321b1bd2e6c8b5f38146c115c8982438f06.zip |
drivers: memory: Introduce Marvell EBU Device Bus driver
Marvell EBU SoCs such as Armada 370/XP, Orion5x (88f5xxx) and
Discovery (mv78xx0) supports a Device Bus controller to access several
kinds of memories and I/O devices (NOR, NAND, SRAM, FPGA).
This commit adds a driver to handle this controller. So far only
Armada 370, Armada XP and Discovery SoCs are supported.
The driver must be registered through a device tree node;
as explained in the binding document.
For each child node in the device tree, this driver will:
* set timing parameters
* register a child device
* setup an address decoding window, using the mbus driver
Keep in mind the address decoding window setup is only a temporary hack.
This code will be removed from this devbus driver as soon as a proper device
tree binding for the mbus driver is added.
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/memory/mvebu-devbus.c')
-rw-r--r-- | drivers/memory/mvebu-devbus.c | 340 |
1 files changed, 340 insertions, 0 deletions
diff --git a/drivers/memory/mvebu-devbus.c b/drivers/memory/mvebu-devbus.c new file mode 100644 index 000000000000..978e8e3abc5c --- /dev/null +++ b/drivers/memory/mvebu-devbus.c @@ -0,0 +1,340 @@ +/* + * Marvell EBU SoC Device Bus Controller + * (memory controller for NOR/NAND/SRAM/FPGA devices) + * + * Copyright (C) 2013 Marvell + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/mbus.h> +#include <linux/of_platform.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> + +/* Register definitions */ +#define DEV_WIDTH_BIT 30 +#define BADR_SKEW_BIT 28 +#define RD_HOLD_BIT 23 +#define ACC_NEXT_BIT 17 +#define RD_SETUP_BIT 12 +#define ACC_FIRST_BIT 6 + +#define SYNC_ENABLE_BIT 24 +#define WR_HIGH_BIT 16 +#define WR_LOW_BIT 8 + +#define READ_PARAM_OFFSET 0x0 +#define WRITE_PARAM_OFFSET 0x4 + +static const char * const devbus_wins[] = { + "devbus-boot", + "devbus-cs0", + "devbus-cs1", + "devbus-cs2", + "devbus-cs3", +}; + +struct devbus_read_params { + u32 bus_width; + u32 badr_skew; + u32 turn_off; + u32 acc_first; + u32 acc_next; + u32 rd_setup; + u32 rd_hold; +}; + +struct devbus_write_params { + u32 sync_enable; + u32 wr_high; + u32 wr_low; + u32 ale_wr; +}; + +struct devbus { + struct device *dev; + void __iomem *base; + unsigned long tick_ps; +}; + +static int get_timing_param_ps(struct devbus *devbus, + struct device_node *node, + const char *name, + u32 *ticks) +{ + u32 time_ps; + int err; + + err = of_property_read_u32(node, name, &time_ps); + if (err < 0) { + dev_err(devbus->dev, "%s has no '%s' property\n", + name, node->full_name); + return err; + } + + *ticks = (time_ps + devbus->tick_ps - 1) / devbus->tick_ps; + + dev_dbg(devbus->dev, "%s: %u ps -> 0x%x\n", + name, time_ps, *ticks); + return 0; +} + +static int devbus_set_timing_params(struct devbus *devbus, + struct device_node *node) +{ + struct devbus_read_params r; + struct devbus_write_params w; + u32 value; + int err; + + dev_dbg(devbus->dev, "Setting timing parameter, tick is %lu ps\n", + devbus->tick_ps); + + /* Get read timings */ + err = of_property_read_u32(node, "devbus,bus-width", &r.bus_width); + if (err < 0) { + dev_err(devbus->dev, + "%s has no 'devbus,bus-width' property\n", + node->full_name); + return err; + } + /* Convert bit width to byte width */ + r.bus_width /= 8; + + err = get_timing_param_ps(devbus, node, "devbus,badr-skew-ps", + &r.badr_skew); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,turn-off-ps", + &r.turn_off); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,acc-first-ps", + &r.acc_first); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,acc-next-ps", + &r.acc_next); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,rd-setup-ps", + &r.rd_setup); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,rd-hold-ps", + &r.rd_hold); + if (err < 0) + return err; + + /* Get write timings */ + err = of_property_read_u32(node, "devbus,sync-enable", + &w.sync_enable); + if (err < 0) { + dev_err(devbus->dev, + "%s has no 'devbus,sync-enable' property\n", + node->full_name); + return err; + } + + err = get_timing_param_ps(devbus, node, "devbus,ale-wr-ps", + &w.ale_wr); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,wr-low-ps", + &w.wr_low); + if (err < 0) + return err; + + err = get_timing_param_ps(devbus, node, "devbus,wr-high-ps", + &w.wr_high); + if (err < 0) + return err; + + /* Set read timings */ + value = r.bus_width << DEV_WIDTH_BIT | + r.badr_skew << BADR_SKEW_BIT | + r.rd_hold << RD_HOLD_BIT | + r.acc_next << ACC_NEXT_BIT | + r.rd_setup << RD_SETUP_BIT | + r.acc_first << ACC_FIRST_BIT | + r.turn_off; + + dev_dbg(devbus->dev, "read parameters register 0x%p = 0x%x\n", + devbus->base + READ_PARAM_OFFSET, + value); + + writel(value, devbus->base + READ_PARAM_OFFSET); + + /* Set write timings */ + value = w.sync_enable << SYNC_ENABLE_BIT | + w.wr_low << WR_LOW_BIT | + w.wr_high << WR_HIGH_BIT | + w.ale_wr; + + dev_dbg(devbus->dev, "write parameters register: 0x%p = 0x%x\n", + devbus->base + WRITE_PARAM_OFFSET, + value); + + writel(value, devbus->base + WRITE_PARAM_OFFSET); + + return 0; +} + +static int mvebu_devbus_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *node = pdev->dev.of_node; + struct device_node *parent; + struct devbus *devbus; + struct resource *res; + struct clk *clk; + unsigned long rate; + const __be32 *ranges; + int err, cs; + int addr_cells, p_addr_cells, size_cells; + int ranges_len, tuple_len; + u32 base, size; + + devbus = devm_kzalloc(&pdev->dev, sizeof(struct devbus), GFP_KERNEL); + if (!devbus) + return -ENOMEM; + + devbus->dev = dev; + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + devbus->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(devbus->base)) + return PTR_ERR(devbus->base); + + clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + clk_prepare_enable(clk); + + /* + * Obtain clock period in picoseconds, + * we need this in order to convert timing + * parameters from cycles to picoseconds. + */ + rate = clk_get_rate(clk) / 1000; + devbus->tick_ps = 1000000000 / rate; + + /* Read the device tree node and set the new timing parameters */ + err = devbus_set_timing_params(devbus, node); + if (err < 0) + return err; + + /* + * Allocate an address window for this device. + * If the device probing fails, then we won't be able to + * remove the allocated address decoding window. + * + * FIXME: This is only a temporary hack! We need to do this here + * because we still don't have device tree bindings for mbus. + * Once that support is added, we will declare these address windows + * statically in the device tree, and remove the window configuration + * from here. + */ + + /* + * Get the CS to choose the window string. + * This is a bit hacky, but it will be removed once the + * address windows are declared in the device tree. + */ + cs = (((unsigned long)devbus->base) % 0x400) / 8; + + /* + * Parse 'ranges' property to obtain a (base,size) window tuple. + * This will be removed once the address windows + * are declared in the device tree. + */ + parent = of_get_parent(node); + if (!parent) + return -EINVAL; + + p_addr_cells = of_n_addr_cells(parent); + of_node_put(parent); + + addr_cells = of_n_addr_cells(node); + size_cells = of_n_size_cells(node); + tuple_len = (p_addr_cells + addr_cells + size_cells) * sizeof(__be32); + + ranges = of_get_property(node, "ranges", &ranges_len); + if (ranges == NULL || ranges_len != tuple_len) + return -EINVAL; + + base = of_translate_address(node, ranges + addr_cells); + if (base == OF_BAD_ADDR) + return -EINVAL; + size = of_read_number(ranges + addr_cells + p_addr_cells, size_cells); + + /* + * Create an mbus address windows. + * FIXME: Remove this, together with the above code, once the + * address windows are declared in the device tree. + */ + err = mvebu_mbus_add_window(devbus_wins[cs], base, size); + if (err < 0) + return err; + + /* + * We need to create a child device explicitly from here to + * guarantee that the child will be probed after the timing + * parameters for the bus are written. + */ + err = of_platform_populate(node, NULL, NULL, dev); + if (err < 0) { + mvebu_mbus_del_window(base, size); + return err; + } + + return 0; +} + +static const struct of_device_id mvebu_devbus_of_match[] = { + { .compatible = "marvell,mvebu-devbus" }, + {}, +}; +MODULE_DEVICE_TABLE(of, mvebu_devbus_of_match); + +static struct platform_driver mvebu_devbus_driver = { + .probe = mvebu_devbus_probe, + .driver = { + .name = "mvebu-devbus", + .owner = THIS_MODULE, + .of_match_table = mvebu_devbus_of_match, + }, +}; + +static int __init mvebu_devbus_init(void) +{ + return platform_driver_register(&mvebu_devbus_driver); +} +module_init(mvebu_devbus_init); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Ezequiel Garcia <ezequiel.garcia@free-electrons.com>"); +MODULE_DESCRIPTION("Marvell EBU SoC Device Bus controller"); |