blob: 852ffe013d326eba680c7060ebda1b17e3d35f5f [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2022 Jonathan Neuschäfer
#include <linux/clk.h>
#include <linux/mfd/syscon.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/spi/spi-mem.h>
#define FIU_CFG 0x00
#define FIU_BURST_BFG 0x01
#define FIU_RESP_CFG 0x02
#define FIU_CFBB_PROT 0x03
#define FIU_FWIN1_LOW 0x04
#define FIU_FWIN1_HIGH 0x06
#define FIU_FWIN2_LOW 0x08
#define FIU_FWIN2_HIGH 0x0a
#define FIU_FWIN3_LOW 0x0c
#define FIU_FWIN3_HIGH 0x0e
#define FIU_PROT_LOCK 0x10
#define FIU_PROT_CLEAR 0x11
#define FIU_SPI_FL_CFG 0x14
#define FIU_UMA_CODE 0x16
#define FIU_UMA_AB0 0x17
#define FIU_UMA_AB1 0x18
#define FIU_UMA_AB2 0x19
#define FIU_UMA_DB0 0x1a
#define FIU_UMA_DB1 0x1b
#define FIU_UMA_DB2 0x1c
#define FIU_UMA_DB3 0x1d
#define FIU_UMA_CTS 0x1e
#define FIU_UMA_ECTS 0x1f
#define FIU_BURST_CFG_R16 3
#define FIU_UMA_CTS_D_SIZE(x) (x)
#define FIU_UMA_CTS_A_SIZE BIT(3)
#define FIU_UMA_CTS_WR BIT(4)
#define FIU_UMA_CTS_CS(x) ((x) << 5)
#define FIU_UMA_CTS_EXEC_DONE BIT(7)
#define SHM_FLASH_SIZE 0x02
#define SHM_FLASH_SIZE_STALL_HOST BIT(6)
/*
* I observed a typical wait time of 16 iterations for a UMA transfer to
* finish, so this should be a safe limit.
*/
#define UMA_WAIT_ITERATIONS 100
/* The memory-mapped view of flash is 16 MiB long */
#define MAX_MEMORY_SIZE_PER_CS (16 << 20)
#define MAX_MEMORY_SIZE_TOTAL (4 * MAX_MEMORY_SIZE_PER_CS)
struct wpcm_fiu_spi {
struct device *dev;
struct clk *clk;
void __iomem *regs;
void __iomem *memory;
size_t memory_size;
struct regmap *shm_regmap;
};
static void wpcm_fiu_set_opcode(struct wpcm_fiu_spi *fiu, u8 opcode)
{
writeb(opcode, fiu->regs + FIU_UMA_CODE);
}
static void wpcm_fiu_set_addr(struct wpcm_fiu_spi *fiu, u32 addr)
{
writeb((addr >> 0) & 0xff, fiu->regs + FIU_UMA_AB0);
writeb((addr >> 8) & 0xff, fiu->regs + FIU_UMA_AB1);
writeb((addr >> 16) & 0xff, fiu->regs + FIU_UMA_AB2);
}
static void wpcm_fiu_set_data(struct wpcm_fiu_spi *fiu, const u8 *data, unsigned int nbytes)
{
int i;
for (i = 0; i < nbytes; i++)
writeb(data[i], fiu->regs + FIU_UMA_DB0 + i);
}
static void wpcm_fiu_get_data(struct wpcm_fiu_spi *fiu, u8 *data, unsigned int nbytes)
{
int i;
for (i = 0; i < nbytes; i++)
data[i] = readb(fiu->regs + FIU_UMA_DB0 + i);
}
/*
* Perform a UMA (User Mode Access) operation, i.e. a software-controlled SPI transfer.
*/
static int wpcm_fiu_do_uma(struct wpcm_fiu_spi *fiu, unsigned int cs,
bool use_addr, bool write, int data_bytes)
{
int i = 0;
u8 cts = FIU_UMA_CTS_EXEC_DONE | FIU_UMA_CTS_CS(cs);
if (use_addr)
cts |= FIU_UMA_CTS_A_SIZE;
if (write)
cts |= FIU_UMA_CTS_WR;
cts |= FIU_UMA_CTS_D_SIZE(data_bytes);
writeb(cts, fiu->regs + FIU_UMA_CTS);
for (i = 0; i < UMA_WAIT_ITERATIONS; i++)
if (!(readb(fiu->regs + FIU_UMA_CTS) & FIU_UMA_CTS_EXEC_DONE))
return 0;
dev_info(fiu->dev, "UMA transfer has not finished in %d iterations\n", UMA_WAIT_ITERATIONS);
return -EIO;
}
static void wpcm_fiu_ects_assert(struct wpcm_fiu_spi *fiu, unsigned int cs)
{
u8 ects = readb(fiu->regs + FIU_UMA_ECTS);
ects &= ~BIT(cs);
writeb(ects, fiu->regs + FIU_UMA_ECTS);
}
static void wpcm_fiu_ects_deassert(struct wpcm_fiu_spi *fiu, unsigned int cs)
{
u8 ects = readb(fiu->regs + FIU_UMA_ECTS);
ects |= BIT(cs);
writeb(ects, fiu->regs + FIU_UMA_ECTS);
}
struct wpcm_fiu_op_shape {
bool (*match)(const struct spi_mem_op *op);
int (*exec)(struct spi_mem *mem, const struct spi_mem_op *op);
};
static bool wpcm_fiu_normal_match(const struct spi_mem_op *op)
{
// Opcode 0x0b (FAST READ) is treated differently in hardware
if (op->cmd.opcode == 0x0b)
return false;
return (op->addr.nbytes == 0 || op->addr.nbytes == 3) &&
op->dummy.nbytes == 0 && op->data.nbytes <= 4;
}
static int wpcm_fiu_normal_exec(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
int ret;
wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
wpcm_fiu_set_addr(fiu, op->addr.val);
if (op->data.dir == SPI_MEM_DATA_OUT)
wpcm_fiu_set_data(fiu, op->data.buf.out, op->data.nbytes);
ret = wpcm_fiu_do_uma(fiu, spi_get_chipselect(mem->spi, 0), op->addr.nbytes == 3,
op->data.dir == SPI_MEM_DATA_OUT, op->data.nbytes);
if (op->data.dir == SPI_MEM_DATA_IN)
wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
return ret;
}
static bool wpcm_fiu_fast_read_match(const struct spi_mem_op *op)
{
return op->cmd.opcode == 0x0b && op->addr.nbytes == 3 &&
op->dummy.nbytes == 1 &&
op->data.nbytes >= 1 && op->data.nbytes <= 4 &&
op->data.dir == SPI_MEM_DATA_IN;
}
static int wpcm_fiu_fast_read_exec(struct spi_mem *mem, const struct spi_mem_op *op)
{
return -EINVAL;
}
/*
* 4-byte addressing.
*
* Flash view: [ C A A A A D D D D]
* bytes: 13 aa bb cc dd -> 5a a5 f0 0f
* FIU's view: [ C A A A][ C D D D D]
* FIU mode: [ read/write][ read ]
*/
static bool wpcm_fiu_4ba_match(const struct spi_mem_op *op)
{
return op->addr.nbytes == 4 && op->dummy.nbytes == 0 && op->data.nbytes <= 4;
}
static int wpcm_fiu_4ba_exec(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
int cs = spi_get_chipselect(mem->spi, 0);
wpcm_fiu_ects_assert(fiu, cs);
wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
wpcm_fiu_set_addr(fiu, op->addr.val >> 8);
wpcm_fiu_do_uma(fiu, cs, true, false, 0);
wpcm_fiu_set_opcode(fiu, op->addr.val & 0xff);
wpcm_fiu_set_addr(fiu, 0);
if (op->data.dir == SPI_MEM_DATA_OUT)
wpcm_fiu_set_data(fiu, op->data.buf.out, op->data.nbytes);
wpcm_fiu_do_uma(fiu, cs, false, op->data.dir == SPI_MEM_DATA_OUT, op->data.nbytes);
wpcm_fiu_ects_deassert(fiu, cs);
if (op->data.dir == SPI_MEM_DATA_IN)
wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
return 0;
}
/*
* RDID (Read Identification) needs special handling because Linux expects to
* be able to read 6 ID bytes and FIU can only read up to 4 at once.
*
* We're lucky in this case, because executing the RDID instruction twice will
* result in the same result.
*
* What we do is as follows (C: write command/opcode byte, D: read data byte,
* A: write address byte):
*
* 1. C D D D
* 2. C A A A D D D
*/
static bool wpcm_fiu_rdid_match(const struct spi_mem_op *op)
{
return op->cmd.opcode == 0x9f && op->addr.nbytes == 0 &&
op->dummy.nbytes == 0 && op->data.nbytes == 6 &&
op->data.dir == SPI_MEM_DATA_IN;
}
static int wpcm_fiu_rdid_exec(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
int cs = spi_get_chipselect(mem->spi, 0);
/* First transfer */
wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
wpcm_fiu_set_addr(fiu, 0);
wpcm_fiu_do_uma(fiu, cs, false, false, 3);
wpcm_fiu_get_data(fiu, op->data.buf.in, 3);
/* Second transfer */
wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
wpcm_fiu_set_addr(fiu, 0);
wpcm_fiu_do_uma(fiu, cs, true, false, 3);
wpcm_fiu_get_data(fiu, op->data.buf.in + 3, 3);
return 0;
}
/*
* With some dummy bytes.
*
* C A A A X* X D D D D
* [C A A A D*][C D D D D]
*/
static bool wpcm_fiu_dummy_match(const struct spi_mem_op *op)
{
// Opcode 0x0b (FAST READ) is treated differently in hardware
if (op->cmd.opcode == 0x0b)
return false;
return (op->addr.nbytes == 0 || op->addr.nbytes == 3) &&
op->dummy.nbytes >= 1 && op->dummy.nbytes <= 5 &&
op->data.nbytes <= 4;
}
static int wpcm_fiu_dummy_exec(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
int cs = spi_get_chipselect(mem->spi, 0);
wpcm_fiu_ects_assert(fiu, cs);
/* First transfer */
wpcm_fiu_set_opcode(fiu, op->cmd.opcode);
wpcm_fiu_set_addr(fiu, op->addr.val);
wpcm_fiu_do_uma(fiu, cs, op->addr.nbytes != 0, true, op->dummy.nbytes - 1);
/* Second transfer */
wpcm_fiu_set_opcode(fiu, 0);
wpcm_fiu_set_addr(fiu, 0);
wpcm_fiu_do_uma(fiu, cs, false, false, op->data.nbytes);
wpcm_fiu_get_data(fiu, op->data.buf.in, op->data.nbytes);
wpcm_fiu_ects_deassert(fiu, cs);
return 0;
}
static const struct wpcm_fiu_op_shape wpcm_fiu_op_shapes[] = {
{ .match = wpcm_fiu_normal_match, .exec = wpcm_fiu_normal_exec },
{ .match = wpcm_fiu_fast_read_match, .exec = wpcm_fiu_fast_read_exec },
{ .match = wpcm_fiu_4ba_match, .exec = wpcm_fiu_4ba_exec },
{ .match = wpcm_fiu_rdid_match, .exec = wpcm_fiu_rdid_exec },
{ .match = wpcm_fiu_dummy_match, .exec = wpcm_fiu_dummy_exec },
};
static const struct wpcm_fiu_op_shape *wpcm_fiu_find_op_shape(const struct spi_mem_op *op)
{
size_t i;
for (i = 0; i < ARRAY_SIZE(wpcm_fiu_op_shapes); i++) {
const struct wpcm_fiu_op_shape *shape = &wpcm_fiu_op_shapes[i];
if (shape->match(op))
return shape;
}
return NULL;
}
static bool wpcm_fiu_supports_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
if (!spi_mem_default_supports_op(mem, op))
return false;
if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
return false;
if (op->cmd.buswidth > 1 || op->addr.buswidth > 1 ||
op->dummy.buswidth > 1 || op->data.buswidth > 1)
return false;
return wpcm_fiu_find_op_shape(op) != NULL;
}
/*
* In order to ensure the integrity of SPI transfers performed via UMA,
* temporarily disable (stall) memory accesses coming from the host CPU.
*/
static void wpcm_fiu_stall_host(struct wpcm_fiu_spi *fiu, bool stall)
{
if (fiu->shm_regmap) {
int res = regmap_update_bits(fiu->shm_regmap, SHM_FLASH_SIZE,
SHM_FLASH_SIZE_STALL_HOST,
stall ? SHM_FLASH_SIZE_STALL_HOST : 0);
if (res)
dev_warn(fiu->dev, "Failed to (un)stall host memory accesses: %d\n", res);
}
}
static int wpcm_fiu_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(mem->spi->controller);
const struct wpcm_fiu_op_shape *shape = wpcm_fiu_find_op_shape(op);
wpcm_fiu_stall_host(fiu, true);
if (shape)
return shape->exec(mem, op);
wpcm_fiu_stall_host(fiu, false);
return -ENOTSUPP;
}
static int wpcm_fiu_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
{
if (op->data.nbytes > 4)
op->data.nbytes = 4;
return 0;
}
static int wpcm_fiu_dirmap_create(struct spi_mem_dirmap_desc *desc)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(desc->mem->spi->controller);
int cs = spi_get_chipselect(desc->mem->spi, 0);
if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
return -ENOTSUPP;
/*
* Unfortunately, FIU only supports a 16 MiB direct mapping window (per
* attached flash chip), but the SPI MEM core doesn't support partial
* direct mappings. This means that we can't support direct mapping on
* flashes that are bigger than 16 MiB.
*/
if (desc->info.offset + desc->info.length > MAX_MEMORY_SIZE_PER_CS)
return -ENOTSUPP;
/* Don't read past the memory window */
if (cs * MAX_MEMORY_SIZE_PER_CS + desc->info.offset + desc->info.length > fiu->memory_size)
return -ENOTSUPP;
return 0;
}
static ssize_t wpcm_fiu_direct_read(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, void *buf)
{
struct wpcm_fiu_spi *fiu = spi_controller_get_devdata(desc->mem->spi->controller);
int cs = spi_get_chipselect(desc->mem->spi, 0);
if (offs >= MAX_MEMORY_SIZE_PER_CS)
return -ENOTSUPP;
offs += cs * MAX_MEMORY_SIZE_PER_CS;
if (!fiu->memory || offs >= fiu->memory_size)
return -ENOTSUPP;
len = min_t(size_t, len, fiu->memory_size - offs);
memcpy_fromio(buf, fiu->memory + offs, len);
return len;
}
static const struct spi_controller_mem_ops wpcm_fiu_mem_ops = {
.adjust_op_size = wpcm_fiu_adjust_op_size,
.supports_op = wpcm_fiu_supports_op,
.exec_op = wpcm_fiu_exec_op,
.dirmap_create = wpcm_fiu_dirmap_create,
.dirmap_read = wpcm_fiu_direct_read,
};
static void wpcm_fiu_hw_init(struct wpcm_fiu_spi *fiu)
{
/* Configure memory-mapped flash access */
writeb(FIU_BURST_CFG_R16, fiu->regs + FIU_BURST_BFG);
writeb(MAX_MEMORY_SIZE_TOTAL / (512 << 10), fiu->regs + FIU_CFG);
writeb(MAX_MEMORY_SIZE_PER_CS / (512 << 10) | BIT(6), fiu->regs + FIU_SPI_FL_CFG);
/* Deassert all manually asserted chip selects */
writeb(0x0f, fiu->regs + FIU_UMA_ECTS);
}
static int wpcm_fiu_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct spi_controller *ctrl;
struct wpcm_fiu_spi *fiu;
struct resource *res;
ctrl = devm_spi_alloc_master(dev, sizeof(*fiu));
if (!ctrl)
return -ENOMEM;
fiu = spi_controller_get_devdata(ctrl);
fiu->dev = dev;
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control");
fiu->regs = devm_ioremap_resource(dev, res);
if (IS_ERR(fiu->regs)) {
dev_err(dev, "Failed to map registers\n");
return PTR_ERR(fiu->regs);
}
fiu->clk = devm_clk_get_enabled(dev, NULL);
if (IS_ERR(fiu->clk))
return PTR_ERR(fiu->clk);
res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory");
fiu->memory = devm_ioremap_resource(dev, res);
fiu->memory_size = min_t(size_t, resource_size(res), MAX_MEMORY_SIZE_TOTAL);
if (IS_ERR(fiu->memory)) {
dev_err(dev, "Failed to map flash memory window\n");
return PTR_ERR(fiu->memory);
}
fiu->shm_regmap = syscon_regmap_lookup_by_phandle_optional(dev->of_node, "nuvoton,shm");
wpcm_fiu_hw_init(fiu);
ctrl->bus_num = -1;
ctrl->mem_ops = &wpcm_fiu_mem_ops;
ctrl->num_chipselect = 4;
ctrl->dev.of_node = dev->of_node;
/*
* The FIU doesn't include a clock divider, the clock is entirely
* determined by the AHB3 bus clock.
*/
ctrl->min_speed_hz = clk_get_rate(fiu->clk);
ctrl->max_speed_hz = clk_get_rate(fiu->clk);
return devm_spi_register_controller(dev, ctrl);
}
static const struct of_device_id wpcm_fiu_dt_ids[] = {
{ .compatible = "nuvoton,wpcm450-fiu", },
{ }
};
MODULE_DEVICE_TABLE(of, wpcm_fiu_dt_ids);
static struct platform_driver wpcm_fiu_driver = {
.driver = {
.name = "wpcm450-fiu",
.bus = &platform_bus_type,
.of_match_table = wpcm_fiu_dt_ids,
},
.probe = wpcm_fiu_probe,
};
module_platform_driver(wpcm_fiu_driver);
MODULE_DESCRIPTION("Nuvoton WPCM450 FIU SPI controller driver");
MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
MODULE_LICENSE("GPL");