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[96.22.11.200]) by smtp.gmail.com with ESMTPSA id h9sm9645qkn.121.2022.02.03.13.34.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 03 Feb 2022 13:34:45 -0800 (PST) From: Adrien Thierry To: linux-serial@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Adrien Thierry , Jeremy Linton , Greg Kroah-Hartman , Jiri Slaby , Nicolas Saenz Julienne , Florian Fainelli , Ray Jui , Scott Branden , bcm-kernel-feedback-list@broadcom.com Subject: [PATCH v2] serial: 8250_bcm2835aux: Add ACPI support Date: Thu, 3 Feb 2022 16:34:08 -0500 Message-Id: <20220203213408.441407-1-athierry@redhat.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add ACPI support to 8250_bcm2835aux driver. This makes it possible to use the miniuart on the Raspberry Pi with the tianocore/edk2 UEFI firmware. Signed-off-by: Adrien Thierry --- V1 -> V2: Refactored code to remove unnecessary conditional paths and intermediate variables drivers/tty/serial/8250/8250_bcm2835aux.c | 87 ++++++++++++++++++----- 1 file changed, 69 insertions(+), 18 deletions(-) diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial= /8250/8250_bcm2835aux.c index fd95860cd661..b7cec2a3b5f7 100644 --- a/drivers/tty/serial/8250/8250_bcm2835aux.c +++ b/drivers/tty/serial/8250/8250_bcm2835aux.c @@ -12,6 +12,7 @@ * simultaneously to rs485. */ =20 +#include #include #include #include @@ -44,6 +45,10 @@ struct bcm2835aux_data { u32 cntl; }; =20 +struct bcm2835_aux_serial_acpi_driver_data { + resource_size_t offset; +}; + static void bcm2835aux_rs485_start_tx(struct uart_8250_port *up) { if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX)) { @@ -82,8 +87,11 @@ static int bcm2835aux_serial_probe(struct platform_devic= e *pdev) { struct uart_8250_port up =3D { }; struct bcm2835aux_data *data; + struct bcm2835_aux_serial_acpi_driver_data *acpi_data; struct resource *res; int ret; + resource_size_t offset =3D 0; + unsigned int uartclk; =20 /* allocate the custom structure */ data =3D devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); @@ -110,8 +118,11 @@ static int bcm2835aux_serial_probe(struct platform_dev= ice *pdev) =20 /* get the clock - this also enables the HW */ data->clk =3D devm_clk_get(&pdev->dev, NULL); - if (IS_ERR(data->clk)) - return dev_err_probe(&pdev->dev, PTR_ERR(data->clk), "could not get clk\= n"); + if (IS_ERR(data->clk)) { + ret =3D device_property_read_u32(&pdev->dev, "clock-frequency", &uartclk= ); + if (ret) + return dev_err_probe(&pdev->dev, ret, "could not get clk\n"); + } =20 /* get the interrupt */ ret =3D platform_get_irq(pdev, 0); @@ -125,20 +136,47 @@ static int bcm2835aux_serial_probe(struct platform_de= vice *pdev) dev_err(&pdev->dev, "memory resource not found"); return -EINVAL; } - up.port.mapbase =3D res->start; - up.port.mapsize =3D resource_size(res); - - /* Check for a fixed line number */ - ret =3D of_alias_get_id(pdev->dev.of_node, "serial"); - if (ret >=3D 0) - up.port.line =3D ret; - - /* enable the clock as a last step */ - ret =3D clk_prepare_enable(data->clk); - if (ret) { - dev_err(&pdev->dev, "unable to enable uart clock - %d\n", - ret); - return ret; + + if (has_acpi_companion(&pdev->dev)) { + const struct acpi_device_id *match; + + match =3D acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->d= ev); + if (!match) + return -ENODEV; + + acpi_data =3D (struct bcm2835_aux_serial_acpi_driver_data *)match->drive= r_data; + + /* Some UEFI implementations (e.g. tianocore/edk2 for the Raspberry Pi) + * describe the miniuart with a base address that encompasses the auxili= ary + * registers shared between the miniuart and spi. + * + * This is due to historical reasons, see discussion here : + * https://edk2.groups.io/g/devel/topic/87501357#84349 + * + * We need to add the offset between the miniuart and auxiliary + * registers to get the real miniuart base address. + */ + offset =3D acpi_data->offset; + } + + up.port.mapbase =3D res->start + offset; + up.port.mapsize =3D resource_size(res) - offset; + + if (dev_of_node(&pdev->dev)) { + /* Check for a fixed line number */ + ret =3D of_alias_get_id(pdev->dev.of_node, "serial"); + if (ret >=3D 0) + up.port.line =3D ret; + + /* enable the clock as a last step */ + ret =3D clk_prepare_enable(data->clk); + if (ret) { + dev_err(&pdev->dev, "unable to enable uart clock - %d\n", + ret); + return ret; + } + + uartclk =3D clk_get_rate(data->clk); } =20 /* the HW-clock divider for bcm2835aux is 8, @@ -146,7 +184,7 @@ static int bcm2835aux_serial_probe(struct platform_devi= ce *pdev) * so we have to multiply the actual clock by 2 * to get identical baudrates. */ - up.port.uartclk =3D clk_get_rate(data->clk) * 2; + up.port.uartclk =3D uartclk * 2; =20 /* register the port */ ret =3D serial8250_register_8250_port(&up); @@ -159,7 +197,9 @@ static int bcm2835aux_serial_probe(struct platform_devi= ce *pdev) return 0; =20 dis_clk: - clk_disable_unprepare(data->clk); + if (dev_of_node(&pdev->dev)) + clk_disable_unprepare(data->clk); + return ret; } =20 @@ -173,16 +213,27 @@ static int bcm2835aux_serial_remove(struct platform_d= evice *pdev) return 0; } =20 +static const struct bcm2835_aux_serial_acpi_driver_data bcm2835_acpi_data = =3D { + .offset =3D 0x40 +}; + static const struct of_device_id bcm2835aux_serial_match[] =3D { { .compatible =3D "brcm,bcm2835-aux-uart" }, { }, }; MODULE_DEVICE_TABLE(of, bcm2835aux_serial_match); =20 +static const struct acpi_device_id bcm2835aux_serial_acpi_match[] =3D { + { "BCM2836", (kernel_ulong_t)&bcm2835_acpi_data }, + { }, +}; +MODULE_DEVICE_TABLE(acpi, bcm2835aux_serial_acpi_match); + static struct platform_driver bcm2835aux_serial_driver =3D { .driver =3D { .name =3D "bcm2835-aux-uart", .of_match_table =3D bcm2835aux_serial_match, + .acpi_match_table =3D bcm2835aux_serial_acpi_match, }, .probe =3D bcm2835aux_serial_probe, .remove =3D bcm2835aux_serial_remove, base-commit: 1f2cfdd349b7647f438c1e552dc1b983da86d830 --=20 2.34.1