From: Fabio Estevam Date: Thu, 8 Aug 2019 21:01:36 +0000 (-0300) Subject: Revert "i2c: imx: improve the error handling in i2c_imx_dma_request()" X-Git-Tag: v5.4-rc1~322^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e8c220fac415d9f4a994b0c2871b835feac1eb4e;p=platform%2Fkernel%2Flinux-rpi.git Revert "i2c: imx: improve the error handling in i2c_imx_dma_request()" Since commit e1ab9a468e3b ("i2c: imx: improve the error handling in i2c_imx_dma_request()") when booting with the DMA driver as module (such as CONFIG_FSL_EDMA=m) the following endless clk warnings are seen: [ 153.077831] ------------[ cut here ]------------ [ 153.082528] WARNING: CPU: 0 PID: 15 at drivers/clk/clk.c:924 clk_core_disable_lock+0x18/0x24 [ 153.093077] i2c0 already disabled [ 153.096416] Modules linked in: [ 153.099521] CPU: 0 PID: 15 Comm: kworker/0:1 Tainted: G W 5.2.0+ #321 [ 153.107290] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree) [ 153.113772] Workqueue: events deferred_probe_work_func [ 153.118979] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 153.126778] [] (show_stack) from [] (dump_stack+0x9c/0xd4) [ 153.134051] [] (dump_stack) from [] (__warn+0xf8/0x124) [ 153.141056] [] (__warn) from [] (warn_slowpath_fmt+0x38/0x48) [ 153.148580] [] (warn_slowpath_fmt) from [] (clk_core_disable_lock+0x18/0x24) [ 153.157413] [] (clk_core_disable_lock) from [] (i2c_imx_probe+0x554/0x6ec) [ 153.166076] [] (i2c_imx_probe) from [] (platform_drv_probe+0x48/0x98) [ 153.174297] [] (platform_drv_probe) from [] (really_probe+0x1d8/0x2c0) [ 153.182605] [] (really_probe) from [] (driver_probe_device+0x5c/0x174) [ 153.190909] [] (driver_probe_device) from [] (bus_for_each_drv+0x44/0x8c) [ 153.199480] [] (bus_for_each_drv) from [] (__device_attach+0xa0/0x108) [ 153.207782] [] (__device_attach) from [] (bus_probe_device+0x88/0x90) [ 153.215999] [] (bus_probe_device) from [] (deferred_probe_work_func+0x60/0x90) [ 153.225003] [] (deferred_probe_work_func) from [] (process_one_work+0x204/0x634) [ 153.234178] [] (process_one_work) from [] (worker_thread+0x20/0x484) [ 153.242315] [] (worker_thread) from [] (kthread+0x118/0x150) [ 153.249758] [] (kthread) from [] (ret_from_fork+0x14/0x20) [ 153.257006] Exception stack(0xdde43fb0 to 0xdde43ff8) [ 153.262095] 3fa0: 00000000 00000000 00000000 00000000 [ 153.270306] 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 153.278520] 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 [ 153.285159] irq event stamp: 3323022 [ 153.288787] hardirqs last enabled at (3323021): [] _raw_spin_unlock_irq+0x24/0x2c [ 153.297261] hardirqs last disabled at (3323022): [] clk_enable_lock+0x10/0x124 [ 153.305392] softirqs last enabled at (3322092): [] __do_softirq+0x344/0x540 [ 153.313352] softirqs last disabled at (3322081): [] irq_exit+0x10c/0x128 [ 153.320946] ---[ end trace a506731ccd9bd703 ]--- This endless clk warnings behaviour is well explained by Andrey Smirnov: "Allocating DMA after registering I2C adapter can lead to infinite probing loop, for example, consider the following scenario: 1. i2c_imx_probe() is called and successfully registers an I2C adapter via i2c_add_numbered_adapter() 2. As a part of i2c_add_numbered_adapter() new I2C slave devices are added from DT which results in a call to driver_deferred_probe_trigger() 3. i2c_imx_probe() continues and calls i2c_imx_dma_request() which due to lack of proper DMA driver returns -EPROBE_DEFER 4. i2c_imx_probe() fails, removes I2C adapter and returns -EPROBE_DEFER, which places it into deferred probe list 5. Deferred probe work triggered in #2 above kicks in and calls i2c_imx_probe() again thus bringing us to step #1" So revert commit e1ab9a468e3b ("i2c: imx: improve the error handling in i2c_imx_dma_request()") and restore the old behaviour, in order to avoid regressions on existing setups. Cc: Reported-by: Andrey Smirnov Reported-by: Russell King Fixes: e1ab9a468e3b ("i2c: imx: improve the error handling in i2c_imx_dma_request()") Signed-off-by: Fabio Estevam Signed-off-by: Wolfram Sang --- diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index b1b8b938d7f4..15f6cde6452f 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -273,8 +273,8 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx, } /* Functions for DMA support */ -static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, - dma_addr_t phy_addr) +static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, + dma_addr_t phy_addr) { struct imx_i2c_dma *dma; struct dma_slave_config dma_sconfig; @@ -283,7 +283,7 @@ static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL); if (!dma) - return -ENOMEM; + return; dma->chan_tx = dma_request_chan(dev, "tx"); if (IS_ERR(dma->chan_tx)) { @@ -328,7 +328,7 @@ static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx, dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n", dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx)); - return 0; + return; fail_rx: dma_release_channel(dma->chan_rx); @@ -336,8 +336,6 @@ fail_tx: dma_release_channel(dma->chan_tx); fail_al: devm_kfree(dev, dma); - /* return successfully if there is no dma support */ - return ret == -ENODEV ? 0 : ret; } static void i2c_imx_dma_callback(void *arg) @@ -1165,17 +1163,13 @@ static int i2c_imx_probe(struct platform_device *pdev) dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res); dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n", i2c_imx->adapter.name); + dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); /* Init DMA config if supported */ - ret = i2c_imx_dma_request(i2c_imx, phy_addr); - if (ret < 0) - goto del_adapter; + i2c_imx_dma_request(i2c_imx, phy_addr); - dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); return 0; /* Return OK */ -del_adapter: - i2c_del_adapter(&i2c_imx->adapter); clk_notifier_unregister: clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb); rpm_disable: