diff options
Diffstat (limited to 'drivers/fsi/fsi-master-hub.c')
| -rw-r--r-- | drivers/fsi/fsi-master-hub.c | 298 |
1 files changed, 298 insertions, 0 deletions
diff --git a/drivers/fsi/fsi-master-hub.c b/drivers/fsi/fsi-master-hub.c new file mode 100644 index 0000000000..6d8b6e8854 --- /dev/null +++ b/drivers/fsi/fsi-master-hub.c @@ -0,0 +1,298 @@ +// 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_LICENSE("GPL"); |