// SPDX-License-Identifier: GPL-2.0-only
/*
* FSI hub master driver
*
* Copyright (C) IBM Corporation 2016
*/
#include <linux/delay.h>
#include <linux/fsi.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include "fsi-master.h"
#define FSI_ENGID_HUB_MASTER 0x1c
#define FSI_LINK_ENABLE_SETUP_TIME 10 /* in mS */
/*
* FSI hub master support
*
* A hub master increases the number of potential target devices that the
* primary FSI master can access. For each link a primary master supports,
* each of those links can in turn be chained to a hub master with multiple
* links of its own.
*
* The hub is controlled by a set of control registers exposed as a regular fsi
* device (the hub->upstream device), and provides access to the downstream FSI
* bus as through an address range on the slave itself (->addr and ->size).
*
* [This differs from "cascaded" masters, which expose the entire downstream
* bus entirely through the fsi device address range, and so have a smaller
* accessible address space.]
*/
struct fsi_master_hub {
struct fsi_master master;
struct fsi_device *upstream;
uint32_t addr, size; /* slave-relative addr of */
/* master address space */
};
#define to_fsi_master_hub(m) container_of(m, struct fsi_master_hub, master)
static int hub_master_read(struct fsi_master *master, int link,
uint8_t id, uint32_t addr, void *val, size_t size)
{
struct fsi_master_hub *hub = to_fsi_master_hub(master);
if (id != 0)
return -EINVAL;
addr += hub->addr + (link * FSI_HUB_LINK_SIZE);
return fsi_slave_read(hub->upstream->slave, addr, val, size);
}
static int hub_master_write(struct fsi_master *master, int link,
uint8_t id, uint32_t addr, const void *val, size_t size)
{
struct fsi_master_hub *hub = to_fsi_master_hub(master);
if (id != 0)
return -EINVAL;
addr += hub->addr + (link * FSI_HUB_LINK_SIZE);
return fsi_slave_write(hub->upstream->slave, addr, val, size);
}
static int hub_master_break(struct fsi_master *master, int link)
{
uint32_t addr;
__be32 cmd;
addr = 0x4;
cmd = cpu_to_be32(0xc0de0000);
return hub_master_write(master, link, 0, addr, &cmd, sizeof(cmd));
}
static int hub_master_link_enable(struct fsi_master *master, int link,
bool enable)
{
struct fsi_master_hub *hub = to_fsi_master_hub(master);
int idx, bit;
__be32 reg;
int rc;
idx = link / 32;
bit = link % 32;
reg = cpu_to_be32(0x80000000 >> bit);
if (!enable)
return fsi_device_write(hub->upstream, FSI_MCENP0 + (4 * idx),
®, 4);
rc = fsi_device_write(hub->upstream, FSI_MSENP0 + (4 * idx), ®, 4);
if (rc)
return rc;
mdelay(FSI_LINK_ENABLE_SETUP_TIME);
return 0;
}
static void hub_master_release(struct device *dev)
{
struct fsi_master_hub *hub = to_fsi_master_hub(to_fsi_master(dev));
kfree(hub);
}
/* mmode encoders */
static inline u32 fsi_mmode_crs0(u32 x)
{
return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT;
}
static inline u32 fsi_mmode_crs1(u32 x)
{
return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT;
}
static int hub_master_init(struct fsi_master_hub *hub)
{
struct fsi_device *dev = hub->upstream;
__be32 reg;
int rc;
reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
| FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
if (rc)
return rc;
/* Initialize the MFSI (hub master) engine */
reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
| FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(FSI_MECTRL_EOAE | FSI_MECTRL_P8_AUTO_TERM);
rc = fsi_device_write(dev, FSI_MECTRL, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(FSI_MMODE_EIP | FSI_MMODE_ECRC | FSI_MMODE_EPC
| fsi_mmode_crs0(1) | fsi_mmode_crs1(1)
| FSI_MMODE_P8_TO_LSB);
rc = fsi_device_write(dev, FSI_MMODE, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(0xffff0000);
rc = fsi_device_write(dev, FSI_MDLYR, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(~0);
rc = fsi_device_write(dev, FSI_MSENP0, ®, sizeof(reg));
if (rc)
return rc;
/* Leave enabled long enough for master logic to set up */
mdelay(FSI_LINK_ENABLE_SETUP_TIME);
rc = fsi_device_write(dev, FSI_MCENP0, ®, sizeof(reg));
if (rc)
return rc;
rc = fsi_device_read(dev, FSI_MAEB, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK);
rc = fsi_device_write(dev, FSI_MRESP0, ®, sizeof(reg));
if (rc)
return rc;
rc = fsi_device_read(dev, FSI_MLEVP0, ®, sizeof(reg));
if (rc)
return rc;
/* Reset the master bridge */
reg = cpu_to_be32(FSI_MRESB_RST_GEN);
rc = fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg));
if (rc)
return rc;
reg = cpu_to_be32(FSI_MRESB_RST_ERR);
return fsi_device_write(dev, FSI_MRESB0, ®, sizeof(reg));
}
static int hub_master_probe(struct device *dev)
{
struct fsi_device *fsi_dev = to_fsi_dev(dev);
struct fsi_master_hub *hub;
uint32_t reg, links;
__be32 __reg;
int rc;
rc = fsi_device_read(fsi_dev, FSI_MVER, &__reg, sizeof(__reg));
if (rc)
return rc;
reg = be32_to_cpu(__reg);
links = (reg >> 8) & 0xff;
dev_dbg(dev, "hub version %08x (%d links)\n", reg, links);
rc = fsi_slave_claim_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET,
FSI_HUB_LINK_SIZE * links);
if (rc) {
dev_err(dev, "can't claim slave address range for links");
return rc;
}
hub = kzalloc(sizeof(*hub), GFP_KERNEL);
if (!hub) {
rc = -ENOMEM;
goto err_release;
}
hub->addr = FSI_HUB_LINK_OFFSET;
hub->size = FSI_HUB_LINK_SIZE * links;
hub->upstream = fsi_dev;
hub->master.dev.parent = dev;
hub->master.dev.release = hub_master_release;
hub->master.dev.of_node = of_node_get(dev_of_node(dev));
hub->master.n_links = links;
hub->master.read = hub_master_read;
hub->master.write = hub_master_write;
hub->master.send_break = hub_master_break;
hub->master.link_enable = hub_master_link_enable;
dev_set_drvdata(dev, hub);
hub_master_init(hub);
rc = fsi_master_register(&hub->master);
if (rc)
goto err_release;
/* At this point, fsi_master_register performs the device_initialize(),
* and holds the sole reference on master.dev. This means the device
* will be freed (via ->release) during any subsequent call to
* fsi_master_unregister. We add our own reference to it here, so we
* can perform cleanup (in _remove()) without it being freed before
* we're ready.
*/
get_device(&hub->master.dev);
return 0;
err_release:
fsi_slave_release_range(fsi_dev->slave, FSI_HUB_LINK_OFFSET,
FSI_HUB_LINK_SIZE * links);
return rc;
}
static int hub_master_remove(struct device *dev)
{
struct fsi_master_hub *hub = dev_get_drvdata(dev);
fsi_master_unregister(&hub->master);
fsi_slave_release_range(hub->upstream->slave, hub->addr, hub->size);
of_node_put(hub->master.dev.of_node);
/*
* master.dev will likely be ->release()ed after this, which free()s
* the hub
*/
put_device(&hub->master.dev);
return 0;
}
static const struct fsi_device_id hub_master_ids[] = {
{
.engine_type = FSI_ENGID_HUB_MASTER,
.version = FSI_VERSION_ANY,
},
{ 0 }
};
static struct fsi_driver hub_master_driver = {
.id_table = hub_master_ids,
.drv = {
.name = "fsi-master-hub",
.bus = &fsi_bus_type,
.probe = hub_master_probe,
.remove = hub_master_remove,
}
};
module_fsi_driver(hub_master_driver);
MODULE_DESCRIPTION("FSI hub master driver");
MODULE_LICENSE("GPL");
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