You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
115 lines
3.7 KiB
115 lines
3.7 KiB
From a3927566a6d90268423ae58aad12a71b9bf39dd9 Mon Sep 17 00:00:00 2001
|
|
From: Phil Elwell <phil@raspberrypi.org>
|
|
Date: Mon, 6 Mar 2017 09:06:18 +0000
|
|
Subject: [PATCH 028/454] clk-bcm2835: Read max core clock from firmware
|
|
|
|
The VPU is responsible for managing the core clock, usually under
|
|
direction from the bcm2835-cpufreq driver but not via the clk-bcm2835
|
|
driver. Since the core frequency can change without warning, it is
|
|
safer to report the maximum clock rate to users of the core clock -
|
|
I2C, SPI and the mini UART - to err on the safe side when calculating
|
|
clock divisors.
|
|
|
|
If the DT node for the clock driver includes a reference to the
|
|
firmware node, use the firmware API to query the maximum core clock
|
|
instead of reading the divider registers.
|
|
|
|
Prior to this patch, a "100KHz" I2C bus was sometimes clocked at about
|
|
160KHz. In particular, switching to the 4.9 kernel was likely to break
|
|
SenseHAT usage on a Pi3.
|
|
|
|
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
|
|
---
|
|
drivers/clk/bcm/clk-bcm2835.c | 39 ++++++++++++++++++++++++++++++++++-
|
|
1 file changed, 38 insertions(+), 1 deletion(-)
|
|
|
|
--- a/drivers/clk/bcm/clk-bcm2835.c
|
|
+++ b/drivers/clk/bcm/clk-bcm2835.c
|
|
@@ -45,6 +45,7 @@
|
|
#include <linux/platform_device.h>
|
|
#include <linux/slab.h>
|
|
#include <dt-bindings/clock/bcm2835.h>
|
|
+#include <soc/bcm2835/raspberrypi-firmware.h>
|
|
|
|
#define CM_PASSWORD 0x5a000000
|
|
|
|
@@ -299,6 +300,8 @@
|
|
#define LOCK_TIMEOUT_NS 100000000
|
|
#define BCM2835_MAX_FB_RATE 1750000000u
|
|
|
|
+#define VCMSG_ID_CORE_CLOCK 4
|
|
+
|
|
/*
|
|
* Names of clocks used within the driver that need to be replaced
|
|
* with an external parent's name. This array is in the order that
|
|
@@ -317,6 +320,7 @@ static const char *const cprman_parent_n
|
|
struct bcm2835_cprman {
|
|
struct device *dev;
|
|
void __iomem *regs;
|
|
+ struct rpi_firmware *fw;
|
|
spinlock_t regs_lock; /* spinlock for all clocks */
|
|
|
|
/*
|
|
@@ -1032,6 +1036,30 @@ static unsigned long bcm2835_clock_get_r
|
|
return bcm2835_clock_rate_from_divisor(clock, parent_rate, div);
|
|
}
|
|
|
|
+static unsigned long bcm2835_clock_get_rate_vpu(struct clk_hw *hw,
|
|
+ unsigned long parent_rate)
|
|
+{
|
|
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
|
|
+ struct bcm2835_cprman *cprman = clock->cprman;
|
|
+
|
|
+ if (cprman->fw) {
|
|
+ struct {
|
|
+ u32 id;
|
|
+ u32 val;
|
|
+ } packet;
|
|
+
|
|
+ packet.id = VCMSG_ID_CORE_CLOCK;
|
|
+ packet.val = 0;
|
|
+
|
|
+ if (!rpi_firmware_property(cprman->fw,
|
|
+ RPI_FIRMWARE_GET_MAX_CLOCK_RATE,
|
|
+ &packet, sizeof(packet)))
|
|
+ return packet.val;
|
|
+ }
|
|
+
|
|
+ return bcm2835_clock_get_rate(hw, parent_rate);
|
|
+}
|
|
+
|
|
static void bcm2835_clock_wait_busy(struct bcm2835_clock *clock)
|
|
{
|
|
struct bcm2835_cprman *cprman = clock->cprman;
|
|
@@ -1321,7 +1349,7 @@ static int bcm2835_vpu_clock_is_on(struc
|
|
*/
|
|
static const struct clk_ops bcm2835_vpu_clock_clk_ops = {
|
|
.is_prepared = bcm2835_vpu_clock_is_on,
|
|
- .recalc_rate = bcm2835_clock_get_rate,
|
|
+ .recalc_rate = bcm2835_clock_get_rate_vpu,
|
|
.set_rate = bcm2835_clock_set_rate,
|
|
.determine_rate = bcm2835_clock_determine_rate,
|
|
.set_parent = bcm2835_clock_set_parent,
|
|
@@ -2203,6 +2231,7 @@ static int bcm2835_clk_probe(struct plat
|
|
struct resource *res;
|
|
const struct bcm2835_clk_desc *desc;
|
|
const size_t asize = ARRAY_SIZE(clk_desc_array);
|
|
+ struct device_node *fw_node;
|
|
size_t i;
|
|
u32 clk_id;
|
|
int ret;
|
|
@@ -2220,6 +2249,14 @@ static int bcm2835_clk_probe(struct plat
|
|
if (IS_ERR(cprman->regs))
|
|
return PTR_ERR(cprman->regs);
|
|
|
|
+ fw_node = of_parse_phandle(dev->of_node, "firmware", 0);
|
|
+ if (fw_node) {
|
|
+ struct rpi_firmware *fw = rpi_firmware_get(NULL);
|
|
+ if (!fw)
|
|
+ return -EPROBE_DEFER;
|
|
+ cprman->fw = fw;
|
|
+ }
|
|
+
|
|
memset(bcm2835_clk_claimed, 0, sizeof(bcm2835_clk_claimed));
|
|
for (i = 0;
|
|
!of_property_read_u32_index(pdev->dev.of_node, "claim-clocks",
|
|
|