[PATCH 6.12.y 3/4] usb: xhci: simplify handling of Structural Parameters 1 values

[Sasha Levin <sashal@kernel.org>]

From: Niklas Neronin <niklas.neronin@linux.intel.com>

[ Upstream commit df08973556851b29bd78e79db696d992ed1b43f0 ]

The 32-bit read-only HCSPARAMS1 register contains the following fields:
 Bits  7:0   - Number of Device Slots (MaxSlots)
 Bits 18:8   - Number of Interrupters (MaxIntrs)
 Bits 23:19  - Reserved
 Bits 31:24  - Number of Ports (MaxPorts)

Since the register value is constant for the lifetime of the controller,
it is cached in 'xhci->hcs_params1'. However, platform drivers may
override the number of interrupters through a separate variable,
'xhci->max_interrupters', leaving only the maximum slots and ports values
still derived from the cached register.

To simplify the code and improve readability, replace 'xhci->hcs_params1'
with two dedicated 'u8' fields: 'xhci->max_slots' and 'xhci->max_ports'.
These values are initialized once and used directly instead of calling
'HCS_MAX_SLOTS()' and 'HCS_MAX_PORTS()' macros.

This change reduces code clutter without increasing memory usage.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20251119142417.2820519-16-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Adjusted for 6.12, which lacks several later xhci cleanups:

  - The xhci_init() split into xhci_hcd_page_size(),
    xhci_enable_max_dev_slots(), xhci_set_cmd_ring_deq(),
    xhci_set_doorbell_ptr() and xhci_set_dev_notifications() is not
    present, so the xhci_enable_max_dev_slots() hunk is dropped.  The
    equivalent 6.12 code in xhci_mem_init() reads HCSPARAMS1 straight
    from cap_regs and never touched xhci->hcs_params1, so it needs no
    change.

  - The port bandwidth debugfs files (xhci_port_bw_show() and friends)
    do not exist, so that xhci-debugfs.c hunk is dropped.

  - struct xhci_port still uses the 'addr' pointer to PORTSC rather than
    the 'port_reg' pointer to the whole register set, so only the loop
    bound is converted in xhci_setup_port_arrays().

  - 6.12 has one extra user of the removed xhci->hcs_params1 field,
    xhci_try_enable_msi() in xhci-pci.c, which upstream had already
    converted to xhci->max_interrupters before this commit.  Convert it
    here as well, otherwise removing the field breaks the build.  It is
    equivalent: xhci_try_enable_msi() runs from the ->start() callback,
    i.e. after xhci_gen_setup() has clamped xhci->max_interrupters to
    HCS_MAX_INTRS(HCSPARAMS1), and nothing in 6.12 presets it. ]

Stable-dep-of: 78203d5b54a4 ("usb: xhci: bail out of setup if the controller is inaccessible")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/host/xhci-debugfs.c | 10 +++-------
 drivers/usb/host/xhci-hub.c     |  2 +-
 drivers/usb/host/xhci-mem.c     | 31 +++++++++++++------------------
 drivers/usb/host/xhci-pci.c     |  9 ++++-----
 drivers/usb/host/xhci-ring.c    |  6 ++----
 drivers/usb/host/xhci.c         | 15 ++++++++-------
 drivers/usb/host/xhci.h         |  3 ++-
 7 files changed, 33 insertions(+), 43 deletions(-)

diff --git a/drivers/usb/host/xhci-debugfs.c b/drivers/usb/host/xhci-debugfs.c
index 570210e8a8e87..8e334b7553012 100644
--- a/drivers/usb/host/xhci-debugfs.c
+++ b/drivers/usb/host/xhci-debugfs.c
@@ -629,20 +629,16 @@ void xhci_debugfs_remove_slot(struct xhci_hcd *xhci, int slot_id)
 static void xhci_debugfs_create_ports(struct xhci_hcd *xhci,
 				      struct dentry *parent)
 {
-	unsigned int		num_ports;
 	char			port_name[8];
 	struct xhci_port	*port;
 	struct dentry		*dir;
 
-	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
-
 	parent = debugfs_create_dir("ports", parent);
 
-	while (num_ports--) {
-		scnprintf(port_name, sizeof(port_name), "port%02d",
-			  num_ports + 1);
+	for (int i = 0; i < xhci->max_ports; i++) {
+		scnprintf(port_name, sizeof(port_name), "port%02d", i + 1);
 		dir = debugfs_create_dir(port_name, parent);
-		port = &xhci->hw_ports[num_ports];
+		port = &xhci->hw_ports[i];
 		debugfs_create_file("portsc", 0644, dir, port, &port_fops);
 	}
 }
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 49cba1cdd91bb..e2ea59b1bd24f 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -700,7 +700,7 @@ static int xhci_enter_test_mode(struct xhci_hcd *xhci,
 	/* Disable all Device Slots */
 	xhci_dbg(xhci, "Disable all slots\n");
 	spin_unlock_irqrestore(&xhci->lock, *flags);
-	for (i = 1; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
+	for (i = 1; i <= xhci->max_slots; i++) {
 		if (!xhci->devs[i])
 			continue;
 
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 3ef311ca224bc..afe47a79d2528 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -918,7 +918,7 @@ static void xhci_free_virt_devices_depth_first(struct xhci_hcd *xhci, int slot_i
 		/* is this a hub device that added a tt_info to the tts list */
 		if (tt_info->slot_id == slot_id) {
 			/* are any devices using this tt_info? */
-			for (i = 1; i < HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
+			for (i = 1; i < xhci->max_slots; i++) {
 				vdev = xhci->devs[i];
 				if (vdev && (vdev->tt_info == tt_info))
 					xhci_free_virt_devices_depth_first(
@@ -1864,7 +1864,7 @@ EXPORT_SYMBOL_GPL(xhci_remove_secondary_interrupter);
 void xhci_mem_cleanup(struct xhci_hcd *xhci)
 {
 	struct device	*dev = xhci_to_hcd(xhci)->self.sysdev;
-	int i, j, num_ports;
+	int i, j;
 
 	cancel_delayed_work_sync(&xhci->cmd_timer);
 
@@ -1883,8 +1883,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed command ring");
 	xhci_cleanup_command_queue(xhci);
 
-	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
-	for (i = 0; i < num_ports && xhci->rh_bw; i++) {
+	for (i = 0; i < xhci->max_ports && xhci->rh_bw; i++) {
 		struct xhci_interval_bw_table *bwt = &xhci->rh_bw[i].bw_table;
 		for (j = 0; j < XHCI_MAX_INTERVAL; j++) {
 			struct list_head *ep = &bwt->interval_bw[j].endpoints;
@@ -1893,7 +1892,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 		}
 	}
 
-	for (i = HCS_MAX_SLOTS(xhci->hcs_params1); i > 0; i--)
+	for (i = xhci->max_slots; i > 0; i--)
 		xhci_free_virt_devices_depth_first(xhci, i);
 
 	dma_pool_destroy(xhci->segment_pool);
@@ -1924,7 +1923,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 	if (!xhci->rh_bw)
 		goto no_bw;
 
-	for (i = 0; i < num_ports; i++) {
+	for (i = 0; i < xhci->max_ports; i++) {
 		struct xhci_tt_bw_info *tt, *n;
 		list_for_each_entry_safe(tt, n, &xhci->rh_bw[i].tts, tt_list) {
 			list_del(&tt->tt_list);
@@ -2125,7 +2124,7 @@ static void xhci_create_rhub_port_array(struct xhci_hcd *xhci,
 	if (!rhub->ports)
 		return;
 
-	for (i = 0; i < HCS_MAX_PORTS(xhci->hcs_params1); i++) {
+	for (i = 0; i < xhci->max_ports; i++) {
 		if (xhci->hw_ports[i].rhub != rhub ||
 		    xhci->hw_ports[i].hcd_portnum == DUPLICATE_ENTRY)
 			continue;
@@ -2148,19 +2147,17 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 {
 	void __iomem *base;
 	u32 offset;
-	unsigned int num_ports;
 	int i, j;
 	int cap_count = 0;
 	u32 cap_start;
 	struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
 
-	num_ports = HCS_MAX_PORTS(xhci->hcs_params1);
-	xhci->hw_ports = kcalloc_node(num_ports, sizeof(*xhci->hw_ports),
-				flags, dev_to_node(dev));
+	xhci->hw_ports = kcalloc_node(xhci->max_ports, sizeof(*xhci->hw_ports),
+				      flags, dev_to_node(dev));
 	if (!xhci->hw_ports)
 		return -ENOMEM;
 
-	for (i = 0; i < num_ports; i++) {
+	for (i = 0; i < xhci->max_ports; i++) {
 		xhci->hw_ports[i].addr = &xhci->op_regs->port_regs[i].portsc;
 		xhci->hw_ports[i].hw_portnum = i;
 
@@ -2168,11 +2165,10 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 		init_completion(&xhci->hw_ports[i].u3exit_done);
 	}
 
-	xhci->rh_bw = kcalloc_node(num_ports, sizeof(*xhci->rh_bw), flags,
-				   dev_to_node(dev));
+	xhci->rh_bw = kcalloc_node(xhci->max_ports, sizeof(*xhci->rh_bw), flags, dev_to_node(dev));
 	if (!xhci->rh_bw)
 		return -ENOMEM;
-	for (i = 0; i < num_ports; i++) {
+	for (i = 0; i < xhci->max_ports; i++) {
 		struct xhci_interval_bw_table *bw_table;
 
 		INIT_LIST_HEAD(&xhci->rh_bw[i].tts);
@@ -2204,9 +2200,8 @@ static int xhci_setup_port_arrays(struct xhci_hcd *xhci, gfp_t flags)
 	offset = cap_start;
 
 	while (offset) {
-		xhci_add_in_port(xhci, num_ports, base + offset, cap_count);
-		if (xhci->usb2_rhub.num_ports + xhci->usb3_rhub.num_ports ==
-		    num_ports)
+		xhci_add_in_port(xhci, xhci->max_ports, base + offset, cap_count);
+		if (xhci->usb2_rhub.num_ports + xhci->usb3_rhub.num_ports == xhci->max_ports)
 			break;
 		offset = xhci_find_next_ext_cap(base, offset,
 						XHCI_EXT_CAPS_PROTOCOL);
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index bd33cf6769cf6..2c4dc54b0fcaa 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -163,13 +163,12 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
 
 	/*
 	 * calculate number of MSI-X vectors supported.
-	 * - HCS_MAX_INTRS: the max number of interrupts the host can handle,
-	 *   with max number of interrupters based on the xhci HCSPARAMS1.
+	 * - max_interrupters: the max number of interrupters requested, capped
+	 *   to the number the host can handle based on the xhci HCSPARAMS1.
 	 * - num_online_cpus: maximum MSI-X vectors per CPUs core.
 	 *   Add additional 1 vector to ensure always available interrupt.
 	 */
-	xhci->nvecs = min(num_online_cpus() + 1,
-			  HCS_MAX_INTRS(xhci->hcs_params1));
+	xhci->nvecs = min(num_online_cpus() + 1, xhci->max_interrupters);
 
 	/* TODO: Check with MSI Soc for sysdev */
 	xhci->nvecs = pci_alloc_irq_vectors(pdev, 1, xhci->nvecs,
@@ -898,7 +897,7 @@ static int xhci_pci_poweroff_late(struct usb_hcd *hcd, bool do_wakeup)
 	if (!(xhci->quirks & XHCI_RESET_TO_DEFAULT))
 		return 0;
 
-	for (i = 0; i < HCS_MAX_PORTS(xhci->hcs_params1); i++) {
+	for (i = 0; i < xhci->max_ports; i++) {
 		port = &xhci->hw_ports[i];
 		portsc = readl(port->addr);
 
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9d506409fdf69..62c997d445fcc 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1324,7 +1324,7 @@ void xhci_hc_died(struct xhci_hcd *xhci)
 	xhci_cleanup_command_queue(xhci);
 
 	/* return any pending urbs, remove may be waiting for them */
-	for (i = 0; i <= HCS_MAX_SLOTS(xhci->hcs_params1); i++) {
+	for (i = 0; i <= xhci->max_slots; i++) {
 		if (!xhci->devs[i])
 			continue;
 		for (j = 0; j < 31; j++)
@@ -1954,7 +1954,6 @@ static void handle_port_status(struct xhci_hcd *xhci, union xhci_trb *event)
 	struct usb_hcd *hcd;
 	u32 port_id;
 	u32 portsc, cmd_reg;
-	int max_ports;
 	unsigned int hcd_portnum;
 	struct xhci_bus_state *bus_state;
 	bool bogus_port_status = false;
@@ -1966,9 +1965,8 @@ static void handle_port_status(struct xhci_hcd *xhci, union xhci_trb *event)
 			  "WARN: xHC returned failed port status event\n");
 
 	port_id = GET_PORT_ID(le32_to_cpu(event->generic.field[0]));
-	max_ports = HCS_MAX_PORTS(xhci->hcs_params1);
 
-	if ((port_id <= 0) || (port_id > max_ports)) {
+	if ((port_id <= 0) || (port_id > xhci->max_ports)) {
 		xhci_warn(xhci, "Port change event with invalid port ID %d\n",
 			  port_id);
 		return;
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 70b7c97e615ff..1c414b89b099c 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -276,8 +276,7 @@ static void xhci_zero_64b_regs(struct xhci_hcd *xhci)
 	if (upper_32_bits(val))
 		xhci_write_64(xhci, 0, &xhci->op_regs->cmd_ring);
 
-	intrs = min_t(u32, HCS_MAX_INTRS(xhci->hcs_params1),
-		      ARRAY_SIZE(xhci->run_regs->ir_set));
+	intrs = min_t(u32, xhci->max_interrupters, ARRAY_SIZE(xhci->run_regs->ir_set));
 
 	for (i = 0; i < intrs; i++) {
 		struct xhci_intr_reg __iomem *ir;
@@ -4040,7 +4039,7 @@ int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev)
 		xhci_err(xhci, "Error while assigning device slot ID: %s\n",
 			 xhci_trb_comp_code_string(command->status));
 		xhci_err(xhci, "Max number of devices this xHCI host supports is %u.\n",
-			 HCS_MAX_SLOTS(xhci->hcs_params1));
+			 xhci->max_slots);
 		xhci_free_command(xhci, command);
 		return 0;
 	}
@@ -5225,6 +5224,7 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	 */
 	struct device		*dev = hcd->self.sysdev;
 	int			retval;
+	u32			hcs_params1;
 
 	/* Accept arbitrarily long scatter-gather lists */
 	hcd->self.sg_tablesize = ~0;
@@ -5250,7 +5250,7 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 	xhci->run_regs = hcd->regs +
 		(readl(&xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
 	/* Cache read-only capability registers */
-	xhci->hcs_params1 = readl(&xhci->cap_regs->hcs_params1);
+	hcs_params1 = readl(&xhci->cap_regs->hcs_params1);
 	xhci->hcs_params2 = readl(&xhci->cap_regs->hcs_params2);
 	xhci->hcs_params3 = readl(&xhci->cap_regs->hcs_params3);
 	xhci->hci_version = HC_VERSION(readl(&xhci->cap_regs->hc_capbase));
@@ -5259,10 +5259,11 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
 		xhci->hcc_params2 = readl(&xhci->cap_regs->hcc_params2);
 
 	xhci->dma_mask_bits = 64;
+	xhci->max_slots = HCS_MAX_SLOTS(hcs_params1);
+	xhci->max_ports = HCS_MAX_PORTS(hcs_params1);
 	/* xhci-plat or xhci-pci might have set max_interrupters already */
-	if ((!xhci->max_interrupters) ||
-	    xhci->max_interrupters > HCS_MAX_INTRS(xhci->hcs_params1))
-		xhci->max_interrupters = HCS_MAX_INTRS(xhci->hcs_params1);
+	if ((!xhci->max_interrupters) || xhci->max_interrupters > HCS_MAX_INTRS(hcs_params1))
+		xhci->max_interrupters = HCS_MAX_INTRS(hcs_params1);
 
 	xhci->quirks |= quirks;
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index ccc43473ad90a..2e9a7fa981c20 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1492,7 +1492,6 @@ struct xhci_hcd {
 	struct xhci_doorbell_array __iomem *dba;
 
 	/* Cached register copies of read-only HC data */
-	__u32		hcs_params1;
 	__u32		hcs_params2;
 	__u32		hcs_params3;
 	__u32		hcc_params;
@@ -1503,6 +1502,8 @@ struct xhci_hcd {
 	/* packed release number */
 	u16		hci_version;
 	u16		max_interrupters;
+	u8		max_slots;
+	u8		max_ports;
 	/* imod_interval in ns (I * 250ns) */
 	u32		imod_interval;
 	u32		page_size;
-- 
2.53.0