ACPI 6.1 has a PCC HW-Reduced Communication Subspace type 2 intended for
use on HW-Reduce ACPI Platform, which requires read-modify-write sequence
to acknowledge doorbell interrupt. This patch provides the implementation
for the Communication Subspace Type 2.
Signed-off-by: Hoan Tran <hotran@xxxxxxx>
Reviewed-by: Prashanth Prakash <pprakash@xxxxxxxxxxxxxx>
---
v3
* Remove 2 global structures
* Correct parsing subspace type 1 and subspace type 2
v2
* Remove changes inside "actbl3.h". This file is taken care by ACPICA.
* Parse both subspace type 1 and subspace type 2
* Remove unnecessary variable initialization
* ISR returns IRQ_NONE in case of error
v1
* Initial
drivers/mailbox/pcc.c | 316 ++++++++++++++++++++++++++++++++++++++------------
1 file changed, 245 insertions(+), 71 deletions(-)
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 043828d..08c87fa 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -59,6 +59,7 @@
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/init.h>
+#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/platform_device.h>
#include <linux/mailbox_controller.h>
@@ -68,11 +69,16 @@
#include "mailbox.h"
#define MAX_PCC_SUBSPACES 256
+#define MBOX_IRQ_NAME "pcc-mbox"
static struct mbox_chan *pcc_mbox_channels;
/* Array of cached virtual address for doorbell registers */
static void __iomem **pcc_doorbell_vaddr;
+/* Array of cached virtual address for doorbell ack registers */
+static void __iomem **pcc_doorbell_ack_vaddr;
+/* Array of doorbell interrupts */
+static int *pcc_doorbell_irq;
static struct mbox_controller pcc_mbox_ctrl = {};
/**
@@ -91,6 +97,132 @@ static struct mbox_chan *get_pcc_channel(int id)
return &pcc_mbox_channels[id];
}
+/*
+ * PCC can be used with perf critical drivers such as CPPC
+ * So it makes sense to locally cache the virtual address and
+ * use it to read/write to PCC registers such as doorbell register
+ *
+ * The below read_register and write_registers are used to read and
+ * write from perf critical registers such as PCC doorbell register
+ */
+static int read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
+{
+ int ret_val = 0;
+
+ switch (bit_width) {
+ case 8:
+ *val = readb(vaddr);
+ break;
+ case 16:
+ *val = readw(vaddr);
+ break;
+ case 32:
+ *val = readl(vaddr);
+ break;
+ case 64:
+ *val = readq(vaddr);
+ break;
+ default:
+ pr_debug("Error: Cannot read register of %u bit width",
+ bit_width);
+ ret_val = -EFAULT;
+ break;
+ }
+ return ret_val;
+}
+
+static int write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
+{
+ int ret_val = 0;
+
+ switch (bit_width) {
+ case 8:
+ writeb(val, vaddr);
+ break;
+ case 16:
+ writew(val, vaddr);
+ break;
+ case 32:
+ writel(val, vaddr);
+ break;
+ case 64:
+ writeq(val, vaddr);
+ break;
+ default:
+ pr_debug("Error: Cannot write register of %u bit width",
+ bit_width);
+ ret_val = -EFAULT;
+ break;
+ }
+ return ret_val;
+}
+
+/**
+ * pcc_map_interrupt - Map a PCC subspace GSI to a linux IRQ number
+ * @interrupt: GSI number.
+ * @flags: interrupt flags
+ *
+ * Returns: a valid linux IRQ number on success
+ * 0 or -EINVAL on failure
+ */
+static int pcc_map_interrupt(u32 interrupt, u32 flags)
+{
+ int trigger, polarity;
+
+ if (!interrupt)
+ return 0;
+
+ trigger = (flags & ACPI_PCCT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
+ : ACPI_LEVEL_SENSITIVE;
+
+ polarity = (flags & ACPI_PCCT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
+ : ACPI_ACTIVE_HIGH;
+
+ return acpi_register_gsi(NULL, interrupt, trigger, polarity);
+}
+
+/**
+ * pcc_mbox_irq - PCC mailbox interrupt handler
+ */
+static irqreturn_t pcc_mbox_irq(int irq, void *p)
+{
+ struct acpi_generic_address *doorbell_ack;
+ struct acpi_pcct_hw_reduced *pcct_ss;
+ struct mbox_chan *chan = p;
+ u64 doorbell_ack_preserve;
+ u64 doorbell_ack_write;
+ u64 doorbell_ack_val;
+ int ret;
+
+ pcct_ss = chan->con_priv;
+
+ mbox_chan_received_data(chan, NULL);
+
+ if (pcct_ss->header.type == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
+ struct acpi_pcct_hw_reduced_type2 *pcct2_ss = chan->con_priv;
+ u32 id = chan - pcc_mbox_channels;
+
+ doorbell_ack = &pcct2_ss->doorbell_ack_register;
+ doorbell_ack_preserve = pcct2_ss->ack_preserve_mask;
+ doorbell_ack_write = pcct2_ss->ack_write_mask;
+
+ ret = read_register(pcc_doorbell_ack_vaddr[id],
+ &doorbell_ack_val,
+ doorbell_ack->bit_width);
+ if (ret)
+ return IRQ_NONE;
+
+ ret = write_register(pcc_doorbell_ack_vaddr[id],
+ (doorbell_ack_val & doorbell_ack_preserve)
+ | doorbell_ack_write,
+ doorbell_ack->bit_width);
+ if (ret)
+ return IRQ_NONE;
+ }
+
+ return IRQ_HANDLED;
+}
+
/**
* pcc_mbox_request_channel - PCC clients call this function to
* request a pointer to their PCC subspace, from which they
@@ -135,6 +267,18 @@ struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
chan->txdone_method |= TXDONE_BY_ACK;
+ if (pcc_doorbell_irq[subspace_id] > 0) {
+ int rc;
+
+ rc = devm_request_irq(dev, pcc_doorbell_irq[subspace_id],
+ pcc_mbox_irq, 0, MBOX_IRQ_NAME, chan);
+ if (unlikely(rc)) {
+ dev_err(dev, "failed to register PCC interrupt %d\n",
+ pcc_doorbell_irq[subspace_id]);
+ chan = ERR_PTR(rc);
+ }
+ }
+
spin_unlock_irqrestore(&chan->lock, flags);
return chan;
@@ -149,80 +293,30 @@ EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
*/
void pcc_mbox_free_channel(struct mbox_chan *chan)
{
+ u32 id = chan - pcc_mbox_channels;
unsigned long flags;
if (!chan || !chan->cl)
return;
+ if (id >= pcc_mbox_ctrl.num_chans) {
+ pr_debug("pcc_mbox_free_channel: Invalid mbox_chan passed\n");
+ return;
+ }
+
spin_lock_irqsave(&chan->lock, flags);
chan->cl = NULL;
chan->active_req = NULL;
if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
chan->txdone_method = TXDONE_BY_POLL;
+ if (pcc_doorbell_irq[id] > 0)
+ devm_free_irq(chan->mbox->dev, pcc_doorbell_irq[id], chan);
+
spin_unlock_irqrestore(&chan->lock, flags);
}
EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
-/*
- * PCC can be used with perf critical drivers such as CPPC
- * So it makes sense to locally cache the virtual address and
- * use it to read/write to PCC registers such as doorbell register
- *
- * The below read_register and write_registers are used to read and
- * write from perf critical registers such as PCC doorbell register
- */
-static int read_register(void __iomem *vaddr, u64 *val, unsigned int bit_width)
-{
- int ret_val = 0;
-
- switch (bit_width) {
- case 8:
- *val = readb(vaddr);
- break;
- case 16:
- *val = readw(vaddr);
- break;
- case 32:
- *val = readl(vaddr);
- break;
- case 64:
- *val = readq(vaddr);
- break;
- default:
- pr_debug("Error: Cannot read register of %u bit width",
- bit_width);
- ret_val = -EFAULT;
- break;
- }
- return ret_val;
-}
-
-static int write_register(void __iomem *vaddr, u64 val, unsigned int bit_width)
-{
- int ret_val = 0;
-
- switch (bit_width) {
- case 8:
- writeb(val, vaddr);
- break;
- case 16:
- writew(val, vaddr);
- break;
- case 32:
- writel(val, vaddr);
- break;
- case 64:
- writeq(val, vaddr);
- break;
- default:
- pr_debug("Error: Cannot write register of %u bit width",
- bit_width);
- ret_val = -EFAULT;
- break;
- }
- return ret_val;
-}
/**
* pcc_send_data - Called from Mailbox Controller code. Used
@@ -296,8 +390,10 @@ static int parse_pcc_subspace(struct acpi_subtable_header *header,
if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) {
pcct_ss = (struct acpi_pcct_hw_reduced *) header;
- if (pcct_ss->header.type !=
- ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE) {
+ if ((pcct_ss->header.type !=
+ ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE)
+ && (pcct_ss->header.type !=
+ ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2)) {
pr_err("Incorrect PCC Subspace type detected\n");
return -EINVAL;
}
@@ -307,6 +403,43 @@ static int parse_pcc_subspace(struct acpi_subtable_header *header,
}
/**
+ * pcc_parse_subspace_irq - Parse the PCC IRQ and PCC ACK register
+ * There should be one entry per PCC client.
+ * @id: PCC subspace index.
+ * @pcct_ss: Pointer to the ACPI subtable header under the PCCT.
+ *
+ * Return: 0 for Success, else errno.
+ *
+ * This gets called for each entry in the PCC table.
+ */
+static int pcc_parse_subspace_irq(int id,
+ struct acpi_pcct_hw_reduced *pcct_ss)
+{
+ pcc_doorbell_irq[id] = pcc_map_interrupt(pcct_ss->doorbell_interrupt,
+ (u32)pcct_ss->flags);
+ if (pcc_doorbell_irq[id] <= 0) {
+ pr_err("PCC GSI %d not registered\n",
+ pcct_ss->doorbell_interrupt);
+ return -EINVAL;
+ }
+
+ if (pcct_ss->header.type
+ == ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2) {
+ struct acpi_pcct_hw_reduced_type2 *pcct2_ss = (void *)pcct_ss;
+
+ pcc_doorbell_ack_vaddr[id] = acpi_os_ioremap(
+ pcct2_ss->doorbell_ack_register.address,
+ pcct2_ss->doorbell_ack_register.bit_width / 8);
+ if (!pcc_doorbell_ack_vaddr[id]) {
+ pr_err("Failed to ioremap PCC ACK register\n");
+ return -ENOMEM;
+ }
+ }
+
+ return 0;
+}
+
+/**
* acpi_pcc_probe - Parse the ACPI tree for the PCCT.
*
* Return: 0 for Success, else errno.
@@ -316,7 +449,9 @@ static int __init acpi_pcc_probe(void)
acpi_size pcct_tbl_header_size;
struct acpi_table_header *pcct_tbl;
struct acpi_subtable_header *pcct_entry;
- int count, i;
+ struct acpi_table_pcct *acpi_pcct_tbl;
+ int count, i, rc;
+ int sum = 0;
acpi_status status = AE_OK;
/* Search for PCCT */
@@ -333,37 +468,66 @@ static int __init acpi_pcc_probe(void)
sizeof(struct acpi_table_pcct),
ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE,
parse_pcc_subspace, MAX_PCC_SUBSPACES);
+ sum += (count > 0) ? count : 0;
+
+ count = acpi_table_parse_entries(ACPI_SIG_PCCT,
+ sizeof(struct acpi_table_pcct),
+ ACPI_PCCT_TYPE_HW_REDUCED_SUBSPACE_TYPE2,
+ parse_pcc_subspace, MAX_PCC_SUBSPACES);
+ sum += (count > 0) ? count : 0;
- if (count <= 0) {
+ if (sum == 0 || sum >= MAX_PCC_SUBSPACES) {
pr_err("Error parsing PCC subspaces from PCCT\n");
return -EINVAL;
}
pcc_mbox_channels = kzalloc(sizeof(struct mbox_chan) *
- count, GFP_KERNEL);
-
+ sum, GFP_KERNEL);
if (!pcc_mbox_channels) {
pr_err("Could not allocate space for PCC mbox channels\n");
return -ENOMEM;
}
- pcc_doorbell_vaddr = kcalloc(count, sizeof(void *), GFP_KERNEL);
+ pcc_doorbell_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
if (!pcc_doorbell_vaddr) {
- kfree(pcc_mbox_channels);
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto err_free_mbox;
+ }
+
+ pcc_doorbell_ack_vaddr = kcalloc(sum, sizeof(void *), GFP_KERNEL);
+ if (!pcc_doorbell_ack_vaddr) {
+ rc = -ENOMEM;
+ goto err_free_db_vaddr;
+ }
+
+ pcc_doorbell_irq = kcalloc(sum, sizeof(int), GFP_KERNEL);
+ if (!pcc_doorbell_irq) {
+ rc = -ENOMEM;
+ goto err_free_db_ack_vaddr;
}
/* Point to the first PCC subspace entry */
pcct_entry = (struct acpi_subtable_header *) (
(unsigned long) pcct_tbl + sizeof(struct acpi_table_pcct));
- for (i = 0; i < count; i++) {
+ acpi_pcct_tbl = (struct acpi_table_pcct *) pcct_tbl;
+ if (acpi_pcct_tbl->flags & ACPI_PCCT_DOORBELL)
+ pcc_mbox_ctrl.txdone_irq = true;
+
+ for (i = 0; i < sum; i++) {
struct acpi_generic_address *db_reg;
struct acpi_pcct_hw_reduced *pcct_ss;
pcc_mbox_channels[i].con_priv = pcct_entry;
+ pcct_ss = (struct acpi_pcct_hw_reduced *) pcct_entry;
+
+ if (pcc_mbox_ctrl.txdone_irq) {
+ rc = pcc_parse_subspace_irq(i, pcct_ss);
+ if (rc < 0)
+ goto err;
+ }
+
/* If doorbell is in system memory cache the virt address */
- pcct_ss = (struct acpi_pcct_hw_reduced *)pcct_entry;
db_reg = &pcct_ss->doorbell_register;
if (db_reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
pcc_doorbell_vaddr[i] = acpi_os_ioremap(db_reg->address,
@@ -372,11 +536,21 @@ static int __init acpi_pcc_probe(void)
((unsigned long) pcct_entry + pcct_entry->length);
}
- pcc_mbox_ctrl.num_chans = count;
+ pcc_mbox_ctrl.num_chans = sum;
pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
return 0;
+
+err:
+ kfree(pcc_doorbell_irq);
+err_free_db_ack_vaddr:
+ kfree(pcc_doorbell_ack_vaddr);
+err_free_db_vaddr:
+ kfree(pcc_doorbell_vaddr);
+err_free_mbox:
+ kfree(pcc_mbox_channels);
+ return rc;
}
/**
--
1.9.1
--
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