Commit aca314ef authored by hotran's avatar hotran Committed by Rafael J. Wysocki

mailbox: pcc: Support HW-Reduced Communication Subspace type 2

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: default avatarHoan Tran <hotran@apm.com>
Reviewed-by: default avatarPrashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 3eab887a
......@@ -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;
}
......@@ -306,6 +402,43 @@ static int parse_pcc_subspace(struct acpi_subtable_header *header,
return 0;
}
/**
* 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.
*
......@@ -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;
}
/**
......
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