// SPDX-License-Identifier: GPL-2.0-only
//
// Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
//
// Authors:
// Ramil Zaripov <[email protected]>
// Serge Semin <[email protected]>
//
// Baikal-T1 DW APB SPI and System Boot SPI driver
//
#include <linux/clk.h>
#include <linux/cpumask.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/mux/consumer.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spi/spi-mem.h>
#include <linux/spi/spi.h>
#include "spi-dw.h"
#define BT1_BOOT_DIRMAP 0
#define BT1_BOOT_REGS 1
struct dw_spi_bt1 {
struct dw_spi dws;
struct clk *clk;
struct mux_control *mux;
#ifdef CONFIG_SPI_DW_BT1_DIRMAP
void __iomem *map;
resource_size_t map_len;
#endif
};
#define to_dw_spi_bt1(_ctlr) \
container_of(spi_controller_get_devdata(_ctlr), struct dw_spi_bt1, dws)
typedef int (*dw_spi_bt1_init_cb)(struct platform_device *pdev,
struct dw_spi_bt1 *dwsbt1);
#ifdef CONFIG_SPI_DW_BT1_DIRMAP
static int dw_spi_bt1_dirmap_create(struct spi_mem_dirmap_desc *desc)
{
struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller);
if (!dwsbt1->map ||
!dwsbt1->dws.mem_ops.supports_op(desc->mem, &desc->info.op_tmpl))
return -EOPNOTSUPP;
if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
return -EOPNOTSUPP;
/*
* Make sure the requested region doesn't go out of the physically
* mapped flash memory bounds.
*/
if (desc->info.offset + desc->info.length > dwsbt1->map_len)
return -EINVAL;
return 0;
}
/*
* Directly mapped SPI memory region is only accessible in the dword chunks.
* That's why we have to create a dedicated read-method to copy data from there
* to the passed buffer.
*/
static void dw_spi_bt1_dirmap_copy_from_map(void *to, void __iomem *from, size_t len)
{
size_t shift, chunk;
u32 data;
/*
* We split the copying up into the next three stages: unaligned head,
* aligned body, unaligned tail.
*/
shift = (size_t)from & 0x3;
if (shift) {
chunk = min_t(size_t, 4 - shift, len);
data = readl_relaxed(from - shift);
memcpy(to, (char *)&data + shift, chunk);
from += chunk;
to += chunk;
len -= chunk;
}
while (len >= 4) {
data = readl_relaxed(from);
memcpy(to, &data, 4);
from += 4;
to += 4;
len -= 4;
}
if (len) {
data = readl_relaxed(from);
memcpy(to, &data, len);
}
}
static ssize_t dw_spi_bt1_dirmap_read(struct spi_mem_dirmap_desc *desc,
u64 offs, size_t len, void *buf)
{
struct dw_spi_bt1 *dwsbt1 = to_dw_spi_bt1(desc->mem->spi->controller);
struct dw_spi *dws = &dwsbt1->dws;
struct spi_mem *mem = desc->mem;
struct dw_spi_cfg cfg;
int ret;
/*
* Make sure the requested operation length is valid. Truncate the
* length if it's greater than the length of the MMIO region.
*/
if (offs >= dwsbt1->map_len || !len)
return 0;
len = min_t(size_t, len, dwsbt1->map_len - offs);
/* Collect the controller configuration required by the operation */
cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD;
cfg.dfs = 8;
cfg.ndf = 4;
cfg.freq = mem->spi->max_speed_hz;
/* Make sure the corresponding CS is de-asserted on transmission */
dw_spi_set_cs(mem->spi, false);
dw_spi_enable_chip(dws, 0);
dw_spi_update_config(dws, mem->spi, &cfg);
dw_spi_umask_intr(dws, DW_SPI_INT_RXFI);
dw_spi_enable_chip(dws, 1);
/*
* Enable the transparent mode of the System Boot Controller.
* The SPI core IO should have been locked before calling this method
* so noone would be touching the controller' registers during the
* dirmap operation.
*/
ret = mux_control_select(dwsbt1->mux, BT1_BOOT_DIRMAP);
if (ret)
return ret;
dw_spi_bt1_dirmap_copy_from_map(buf, dwsbt1->map + offs, len);
mux_control_deselect(dwsbt1->mux);
dw_spi_set_cs(mem->spi, true);
ret = dw_spi_check_status(dws, true);
return ret ?: len;
}
#endif /* CONFIG_SPI_DW_BT1_DIRMAP */
static int dw_spi_bt1_std_init(struct platform_device *pdev,
struct dw_spi_bt1 *dwsbt1)
{
struct dw_spi *dws = &dwsbt1->dws;
dws->irq = platform_get_irq(pdev, 0);
if (dws->irq < 0)
return dws->irq;
dws->num_cs = 4;
/*
* Baikal-T1 Normal SPI Controllers don't always keep up with full SPI
* bus speed especially when it comes to the concurrent access to the
* APB bus resources. Thus we have no choice but to set a constraint on
* the SPI bus frequency for the memory operations which require to
* read/write data as fast as possible.
*/
dws->max_mem_freq = 20000000U;
dw_spi_dma_setup_generic(dws);
return 0;
}
static int dw_spi_bt1_sys_init(struct platform_device *pdev,
struct dw_spi_bt1 *dwsbt1)
{
struct resource *mem __maybe_unused;
struct dw_spi *dws = &dwsbt1->dws;
/*
* Baikal-T1 System Boot Controller is equipped with a mux, which
* switches between the directly mapped SPI flash access mode and
* IO access to the DW APB SSI registers. Note the mux controller
* must be setup to preserve the registers being accessible by default
* (on idle-state).
*/
dwsbt1->mux = devm_mux_control_get(&pdev->dev, NULL);
if (IS_ERR(dwsbt1->mux))
return PTR_ERR(dwsbt1->mux);
/*
* Directly mapped SPI flash memory is a 16MB MMIO region, which can be
* used to access a peripheral memory device just by reading/writing
* data from/to it. Note the system APB bus will stall during each IO
* from/to the dirmap region until the operation is finished. So don't
* use it concurrently with time-critical tasks (like the SPI memory
* operations implemented in the DW APB SSI driver).
*/
#ifdef CONFIG_SPI_DW_BT1_DIRMAP
mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (mem) {
dwsbt1->map = devm_ioremap_resource(&pdev->dev, mem);
if (!IS_ERR(dwsbt1->map)) {
dwsbt1->map_len = resource_size(mem);
dws->mem_ops.dirmap_create = dw_spi_bt1_dirmap_create;
dws->mem_ops.dirmap_read = dw_spi_bt1_dirmap_read;
} else {
dwsbt1->map = NULL;
}
}
#endif /* CONFIG_SPI_DW_BT1_DIRMAP */
/*
* There is no IRQ, no DMA and just one CS available on the System Boot
* SPI controller.
*/
dws->irq = IRQ_NOTCONNECTED;
dws->num_cs = 1;
/*
* Baikal-T1 System Boot SPI Controller doesn't keep up with the full
* SPI bus speed due to relatively slow APB bus and races for it'
* resources from different CPUs. The situation is worsen by a small
* FIFOs depth (just 8 words). It works better in a single CPU mode
* though, but still tends to be not fast enough at low CPU
* frequencies.
*/
if (num_possible_cpus() > 1)
dws->max_mem_freq = 10000000U;
else
dws->max_mem_freq = 20000000U;
return 0;
}
static int dw_spi_bt1_probe(struct platform_device *pdev)
{
dw_spi_bt1_init_cb init_func;
struct dw_spi_bt1 *dwsbt1;
struct resource *mem;
struct dw_spi *dws;
int ret;
dwsbt1 = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_bt1), GFP_KERNEL);
if (!dwsbt1)
return -ENOMEM;
dws = &dwsbt1->dws;
dws->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
if (IS_ERR(dws->regs))
return PTR_ERR(dws->regs);
dws->paddr = mem->start;
dwsbt1->clk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(dwsbt1->clk))
return PTR_ERR(dwsbt1->clk);
dws->bus_num = pdev->id;
dws->reg_io_width = 4;
dws->max_freq = clk_get_rate(dwsbt1->clk);
if (!dws->max_freq)
return -EINVAL;
init_func = device_get_match_data(&pdev->dev);
ret = init_func(pdev, dwsbt1);
if (ret)
return ret;
pm_runtime_enable(&pdev->dev);
ret = dw_spi_add_host(&pdev->dev, dws);
if (ret) {
pm_runtime_disable(&pdev->dev);
return ret;
}
platform_set_drvdata(pdev, dwsbt1);
return 0;
}
static void dw_spi_bt1_remove(struct platform_device *pdev)
{
struct dw_spi_bt1 *dwsbt1 = platform_get_drvdata(pdev);
dw_spi_remove_host(&dwsbt1->dws);
pm_runtime_disable(&pdev->dev);
}
static const struct of_device_id dw_spi_bt1_of_match[] = {
{ .compatible = "baikal,bt1-ssi", .data = dw_spi_bt1_std_init},
{ .compatible = "baikal,bt1-sys-ssi", .data = dw_spi_bt1_sys_init},
{ }
};
MODULE_DEVICE_TABLE(of, dw_spi_bt1_of_match);
static struct platform_driver dw_spi_bt1_driver = {
.probe = dw_spi_bt1_probe,
.remove_new = dw_spi_bt1_remove,
.driver = {
.name = "bt1-sys-ssi",
.of_match_table = dw_spi_bt1_of_match,
},
};
module_platform_driver(dw_spi_bt1_driver);
MODULE_AUTHOR("Serge Semin <[email protected]>");
MODULE_DESCRIPTION("Baikal-T1 System Boot SPI Controller driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(SPI_DW_CORE);
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