Thread (15 messages) 15 messages, 5 authors, 2021-02-01

RE: [PATCH 1/1] clk: aspeed: modify some default clks are critical

From: Ryan Chen <ryan_chen@aspeedtech.com>
Date: 2020-09-29 08:37:42
Also in: linux-aspeed, linux-clk, lkml

From: Joel Stanley <joel@jms.id.au>
Sent: Tuesday, September 29, 2020 4:04 PM
To: Ryan Chen <ryan_chen@aspeedtech.com>; Jae Hyun Yoo
[off-list ref]; Andrew Jeffery [off-list ref]
Cc: Michael Turquette <mturquette@baylibre.com>; Stephen Boyd
[off-list ref]; linux-clk@vger.kernel.org; Linux ARM
[off-list ref]; linux-aspeed
[off-list ref]; Linux Kernel Mailing List
[off-list ref]; BMC-SW [off-list ref]
Subject: Re: [PATCH 1/1] clk: aspeed: modify some default clks are critical

On Mon, 28 Sep 2020 at 07:01, Ryan Chen [off-list ref]
wrote:
quoted
In ASPEED SoC LCLK is LPC clock for all SuperIO device, UART1/UART2
are default for Host SuperIO UART device, eSPI clk for Host eSPI bus
access eSPI slave channel, those clks can't be disable should keep
default, otherwise will affect Host side access SuperIO and SPI slave device.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 drivers/clk/clk-aspeed.c  | 8 ++++----  drivers/clk/clk-ast2600.c | 8
++++----
 2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c index
411ff5fb2c07..d348c4fd3f9f 100644
--- a/drivers/clk/clk-aspeed.c
+++ b/drivers/clk/clk-aspeed.c
@@ -54,15 +54,15 @@ static const struct aspeed_gate_data aspeed_gates[]
= {
quoted
        [ASPEED_CLK_GATE_DCLK] =        {  5, -1, "dclk-gate",
NULL,   CLK_IS_CRITICAL }, /* DAC */
quoted
        [ASPEED_CLK_GATE_REFCLK] =      {  6, -1, "refclk-gate",
"clkin", CLK_IS_CRITICAL },
quoted
        [ASPEED_CLK_GATE_USBPORT2CLK] = {  7,  3, "usb-port2-gate",
NULL,   0 }, /* USB2.0 Host port 2 */
quoted
-       [ASPEED_CLK_GATE_LCLK] =        {  8,  5, "lclk-gate",
NULL,   0 }, /* LPC */
quoted
+       [ASPEED_CLK_GATE_LCLK] =        {  8,  5, "lclk-gate",
NULL,   CLK_IS_CRITICAL }, /* LPC */
quoted
        [ASPEED_CLK_GATE_USBUHCICLK] =  {  9, 15, "usb-uhci-gate",
NULL,   0 }, /* USB1.1 (requires port 2 enabled) */
quoted
        [ASPEED_CLK_GATE_D1CLK] =       { 10, 13, "d1clk-gate",
NULL,   0 }, /* GFX CRT */
quoted
        [ASPEED_CLK_GATE_YCLK] =        { 13,  4, "yclk-gate",
NULL,   0 }, /* HAC */
quoted
        [ASPEED_CLK_GATE_USBPORT1CLK] = { 14, 14, "usb-port1-gate",
NULL,   0 }, /* USB2 hub/USB2 host port 1/USB1.1 dev */
quoted
-       [ASPEED_CLK_GATE_UART1CLK] =    { 15, -1, "uart1clk-gate",
"uart", 0 }, /* UART1 */
quoted
-       [ASPEED_CLK_GATE_UART2CLK] =    { 16, -1, "uart2clk-gate",
"uart", 0 }, /* UART2 */
quoted
+       [ASPEED_CLK_GATE_UART1CLK] =    { 15, -1, "uart1clk-gate",
"uart", CLK_IS_CRITICAL }, /* UART1 */
quoted
+       [ASPEED_CLK_GATE_UART2CLK] =    { 16, -1, "uart2clk-gate",
"uart", CLK_IS_CRITICAL }, /* UART2 */
quoted
        [ASPEED_CLK_GATE_UART5CLK] =    { 17, -1, "uart5clk-gate",
"uart", 0 }, /* UART5 */
quoted
-       [ASPEED_CLK_GATE_ESPICLK] =     { 19, -1, "espiclk-gate",
NULL,   0 }, /* eSPI */
quoted
+       [ASPEED_CLK_GATE_ESPICLK] =     { 19, -1, "espiclk-gate",
NULL,   CLK_IS_CRITICAL }, /* eSPI */

This is fine for systems that have eSPI. For systems that do not use eSPI, the
clocks are not "required".

I was sent a similar patch by Jae some time ago:


https://lore.kernel.org/openbmc/697a184b-ef99-a46e-bf98-4d339b3aafd8@lin
ux.intel.com/

Better is to associate drivers with these clocks, and those drivers will ensure
they are left enabled.

Alternatively, we will need to come up with a device tree binding to describe
the hardware requirement that these clocks are left on.
ASPEED BMC SoC have SuperIO device that default enable, even without BMC fw boot.
Host can use SUART1/SUART2/GPIO.... 
That the reason even Linux kernel boot should not change the SoC default clk, that is the impact.

Ryan
quoted
        [ASPEED_CLK_GATE_MAC1CLK] =     { 20, 11, "mac1clk-gate",
"mac",  0 }, /* MAC1 */
quoted
        [ASPEED_CLK_GATE_MAC2CLK] =     { 21, 12, "mac2clk-gate",
"mac",  0 }, /* MAC2 */
quoted
        [ASPEED_CLK_GATE_RSACLK] =      { 24, -1, "rsaclk-gate",
NULL,   0 }, /* RSA */
quoted
diff --git a/drivers/clk/clk-ast2600.c b/drivers/clk/clk-ast2600.c
index bbacaccad554..6802a2d5bbe2 100644
--- a/drivers/clk/clk-ast2600.c
+++ b/drivers/clk/clk-ast2600.c
@@ -86,8 +86,8 @@ static const struct aspeed_gate_data aspeed_g6_gates[]
= {
quoted
        /* Reserved 26 */
        [ASPEED_CLK_GATE_EMMCCLK]       = { 27, 16,
"emmcclk-gate",     NULL,    0 },   /* For card clk */
quoted
        /* Reserved 28/29/30 */
-       [ASPEED_CLK_GATE_LCLK]          = { 32, 32, "lclk-gate",
NULL,    0 }, /* LPC */
quoted
-       [ASPEED_CLK_GATE_ESPICLK]       = { 33, -1, "espiclk-gate",
NULL,    0 }, /* eSPI */
quoted
+       [ASPEED_CLK_GATE_LCLK]          = { 32, 32, "lclk-gate",
NULL,    CLK_IS_CRITICAL }, /* LPC */
quoted
+       [ASPEED_CLK_GATE_ESPICLK]       = { 33, -1, "espiclk-gate",
NULL,    CLK_IS_CRITICAL }, /* eSPI */
quoted
        [ASPEED_CLK_GATE_REF1CLK]       = { 34, -1, "ref1clk-gate",
"clkin", CLK_IS_CRITICAL },
quoted
        /* Reserved 35 */
        [ASPEED_CLK_GATE_SDCLK]         = { 36, 56, "sdclk-gate",
NULL,    0 },   /* SDIO/SD */
quoted
@@ -102,8 +102,8 @@ static const struct aspeed_gate_data
aspeed_g6_gates[] = {
quoted
        [ASPEED_CLK_GATE_I3C5CLK]       = { 45,  45, "i3c5clk-gate",
NULL,    0 },   /* I3C5 */
quoted
        [ASPEED_CLK_GATE_I3C6CLK]       = { 46,  46, "i3c6clk-gate",
NULL,    0 },   /* I3C6 */
quoted
        [ASPEED_CLK_GATE_I3C7CLK]       = { 47,  47, "i3c7clk-gate",
NULL,    0 },   /* I3C7 */
quoted
-       [ASPEED_CLK_GATE_UART1CLK]      = { 48,  -1, "uart1clk-gate",
"uart",  0 },   /* UART1 */
quoted
-       [ASPEED_CLK_GATE_UART2CLK]      = { 49,  -1, "uart2clk-gate",
"uart",  0 },   /* UART2 */
quoted
+       [ASPEED_CLK_GATE_UART1CLK]      = { 48,  -1, "uart1clk-gate",
"uart",  CLK_IS_CRITICAL },     /* UART1 */
quoted
+       [ASPEED_CLK_GATE_UART2CLK]      = { 49,  -1, "uart2clk-gate",
"uart",  CLK_IS_CRITICAL },     /* UART2 */
quoted
        [ASPEED_CLK_GATE_UART3CLK]      = { 50,  -1,
"uart3clk-gate",   "uart",  0 },   /* UART3 */
quoted
        [ASPEED_CLK_GATE_UART4CLK]      = { 51,  -1,
"uart4clk-gate",   "uart",  0 },   /* UART4 */
quoted
        [ASPEED_CLK_GATE_MAC3CLK]       = { 52,  52,
"mac3clk-gate",    "mac34", 0 },   /* MAC3 */
quoted
--
2.17.1
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