[PATCH v8 22/24] drivers/fsi: Add hub master support

From: Christopher Bostic
Date: Tue Jun 06 2017 - 17:10:32 EST

Add an engine driver to expose a "hub" FSI master - which has a set of
control registers in the engine address space, and uses a chunk of the
slave address space for actual FSI communication.

Additional changes from Jeremy Kerr <jk@xxxxxxxxxx>.

Signed-off-by: Christopher Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeremy Kerr <jk@xxxxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
---
drivers/fsi/Kconfig | 8 ++
drivers/fsi/Makefile | 1 +
drivers/fsi/fsi-master-hub.c | 327 +++++++++++++++++++++++++++++++++++++++++++
3 files changed, 336 insertions(+)
create mode 100644 drivers/fsi/fsi-master-hub.c

diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
index 5582523..6821ed0 100644
--- a/drivers/fsi/Kconfig
+++ b/drivers/fsi/Kconfig
@@ -20,6 +20,14 @@ config FSI_MASTER_GPIO
---help---
This option enables a FSI master driver using GPIO lines.

+config FSI_MASTER_HUB
+ tristate "FSI hub master"
+ ---help---
+ This option enables a FSI hub master driver. Hub is a type of FSI
+ master that is connected to the upstream master via a slave. Hubs
+ allow chaining of FSI links to an arbitrary depth. This allows for
+ a high target device fanout.
+
config FSI_SCOM
tristate "SCOM FSI client device driver"
---help---
diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
index 3466f08..65eb99d 100644
--- a/drivers/fsi/Makefile
+++ b/drivers/fsi/Makefile
@@ -1,4 +1,5 @@

obj-$(CONFIG_FSI) += fsi-core.o
+obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
diff --git a/drivers/fsi/fsi-master-hub.c b/drivers/fsi/fsi-master-hub.c
new file mode 100644
index 0000000..133b9bf
--- /dev/null
+++ b/drivers/fsi/fsi-master-hub.c
@@ -0,0 +1,327 @@
+/*
+ * FSI hub master driver
+ *
+ * Copyright (C) IBM Corporation 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/delay.h>
+#include <linux/fsi.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "fsi-master.h"
+
+/* Control Registers */
+#define FSI_MMODE 0x0 /* R/W: mode */
+#define FSI_MDLYR 0x4 /* R/W: delay */
+#define FSI_MCRSP 0x8 /* R/W: clock rate */
+#define FSI_MENP0 0x10 /* R/W: enable */
+#define FSI_MLEVP0 0x18 /* R: plug detect */
+#define FSI_MSENP0 0x18 /* S: Set enable */
+#define FSI_MCENP0 0x20 /* C: Clear enable */
+#define FSI_MAEB 0x70 /* R: Error address */
+#define FSI_MVER 0x74 /* R: master version/type */
+#define FSI_MRESP0 0xd0 /* W: Port reset */
+#define FSI_MESRB0 0x1d0 /* R: Master error status */
+#define FSI_MRESB0 0x1d0 /* W: Reset bridge */
+#define FSI_MECTRL 0x2e0 /* W: Error control */
+
+/* MMODE: Mode control */
+#define FSI_MMODE_EIP 0x80000000 /* Enable interrupt polling */
+#define FSI_MMODE_ECRC 0x40000000 /* Enable error recovery */
+#define FSI_MMODE_EPC 0x10000000 /* Enable parity checking */
+#define FSI_MMODE_P8_TO_LSB 0x00000010 /* Timeout value LSB */
+ /* MSB=1, LSB=0 is 0.8 ms */
+ /* MSB=0, LSB=1 is 0.9 ms */
+#define FSI_MMODE_CRS0SHFT 18 /* Clk rate selection 0 shift */
+#define FSI_MMODE_CRS0MASK 0x3ff /* Clk rate selection 0 mask */
+#define FSI_MMODE_CRS1SHFT 8 /* Clk rate selection 1 shift */
+#define FSI_MMODE_CRS1MASK 0x3ff /* Clk rate selection 1 mask */
+
+/* MRESB: Reset brindge */
+#define FSI_MRESB_RST_GEN 0x80000000 /* General reset */
+#define FSI_MRESB_RST_ERR 0x40000000 /* Error Reset */
+
+/* MRESB: Reset port */
+#define FSI_MRESP_RST_ALL_MASTER 0x20000000 /* Reset all FSI masters */
+#define FSI_MRESP_RST_ALL_LINK 0x10000000 /* Reset all FSI port contr. */
+#define FSI_MRESP_RST_MCR 0x08000000 /* Reset FSI master reg. */
+#define FSI_MRESP_RST_PYE 0x04000000 /* Reset FSI parity error */
+#define FSI_MRESP_RST_ALL 0xfc000000 /* Reset any error */
+
+/* MECTRL: Error control */
+#define FSI_MECTRL_EOAE 0x8000 /* Enable machine check when */
+ /* master 0 in error */
+#define FSI_MECTRL_P8_AUTO_TERM 0x4000 /* Auto terminate */
+
+#define FSI_ENGID_HUB_MASTER 0x1c
+#define FSI_HUB_LINK_OFFSET 0x80000
+#define FSI_HUB_LINK_SIZE 0x80000
+#define FSI_HUB_MASTER_MAX_LINKS 8
+
+#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, 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)
+{
+ 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);
+
+ rc = fsi_device_write(hub->upstream, FSI_MSENP0 + (4 * idx), &reg, 4);
+
+ mdelay(FSI_LINK_ENABLE_SETUP_TIME);
+
+ fsi_device_read(hub->upstream, FSI_MENP0 + (4 * idx), &reg, 4);
+
+ return rc;
+}
+
+static void hub_master_release(struct device *dev)
+{
+ struct fsi_master_hub *hub = to_fsi_master_hub(dev_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, &reg, 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, &reg, 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, &reg, 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, &reg, sizeof(reg));
+ if (rc)
+ return rc;
+
+ reg = cpu_to_be32(0xffff0000);
+ rc = fsi_device_write(dev, FSI_MDLYR, &reg, sizeof(reg));
+ if (rc)
+ return rc;
+
+ reg = ~0;
+ rc = fsi_device_write(dev, FSI_MSENP0, &reg, 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, &reg, sizeof(reg));
+ if (rc)
+ return rc;
+
+ rc = fsi_device_read(dev, FSI_MAEB, &reg, 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, &reg, sizeof(reg));
+ if (rc)
+ return rc;
+
+ rc = fsi_device_read(dev, FSI_MLEVP0, &reg, 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, &reg, sizeof(reg));
+ if (rc)
+ return rc;
+
+ reg = cpu_to_be32(FSI_MRESB_RST_ERR);
+ return fsi_device_write(dev, FSI_MRESB0, &reg, 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_info(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.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)
+ return 0;
+
+ kfree(hub);
+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);
+ return 0;
+}
+
+static 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");
--
1.8.2.2